This document provides an overview and table of contents for the CCNA Routing and Switching Review Guide. It includes chapters covering IP data network operation, LAN switching technologies, IP addressing, IP routing, IP services, network device security, troubleshooting, and WAN technologies. The guide is intended to help readers prepare for the CCNA Routing and Switching certification exam.
The document provides an overview of computer networking fundamentals including:
- The seven layers of the OSI reference model and their functions from physical transmission to application interfaces.
- Reasons for using a layered networking model including modularity, interoperability, and error checking.
- Key networking concepts such as MAC addresses, connection-oriented vs. connectionless transmission, and data encapsulation.
This document discusses Cisco Certified Network Associate (CCNA) certification and networking concepts. It includes:
- An overview of the CCNA certification and what skills it demonstrates in networking areas like LANs, WANs, routing protocols, and network access.
- Explanations of common networking devices, topologies, protocols like IP addressing and routing, and models like the OSI model.
- Descriptions of static and dynamic routing, protocols like RIP, OSPF, EIGRP, and commands used to configure routers.
This document discusses networking devices and technologies used to connect local area networks (LANs) and wide area networks (WANs). It describes common physical layer components used in Ethernet LANs such as twisted pair cable, fiber optic cable, and connectors. It also discusses serial connection options and devices used for WAN connections including CSU/DSUs and their roles as data terminal equipment (DTE) and data circuit-terminating equipment (DCE).
The document provides information about the CCNA certification options and Cisco networking concepts including the OSI model. It can be used to study for the CCNA exam. There are two options to obtain the CCNA: pass a single exam or two exams. The document then explains the OSI model in detail including mnemonics to remember the layer names and summaries of what occurs at each layer of the OSI model to help understand how data flows through a network.
Cisco Packet Tracer is a network simulation program that allows students to experiment with network behavior. The document describes how to set up three example networks using Packet Tracer. It explains how to connect routers and PCs, assign IP addresses to devices, and configure routing protocols to allow communication between the networks. Setting up the example networks demonstrates how to build and test a multi-network topology in Packet Tracer.
The document provides information about CCNA training and certification. It discusses the topics covered in the CCNA exam, recommended training courses, study materials, exam format and structure. The CCNA certification tests knowledge of network fundamentals, switching, routing, WAN technologies, security and management. Exams last 90 minutes and contain around 50-60 multiple choice and simulation questions. Common jobs requiring the CCNA include network administrator, database administrator and help desk technician.
A
PROJECT REPORT
On
CISCO CERTIFIED NETWORK ASSOCIATE
A computer network, or simply a network, is a collection of computer and other hardware components interconnected by communication channels that allow sharing of resources and information. Where at least one process in one device is able to send/receive data to/from at least one process residing in a remote device, then the two devices are said to be in a network. Simply, more than one computer interconnected through a communication medium for information interchange is called a computer network.
This document summarizes network devices and concepts from a CCNA guide. It describes how repeaters, hubs, wireless access points, bridges, switches and routers segment networks and control traffic. It also defines Ethernet, Fast Ethernet and Gigabit Ethernet standards, and explains half and full-duplex communication modes. The summary provides an overview of common network devices and technologies for local area networks.
The document provides an overview of computer networking fundamentals including:
- The seven layers of the OSI reference model and their functions from physical transmission to application interfaces.
- Reasons for using a layered networking model including modularity, interoperability, and error checking.
- Key networking concepts such as MAC addresses, connection-oriented vs. connectionless transmission, and data encapsulation.
This document discusses Cisco Certified Network Associate (CCNA) certification and networking concepts. It includes:
- An overview of the CCNA certification and what skills it demonstrates in networking areas like LANs, WANs, routing protocols, and network access.
- Explanations of common networking devices, topologies, protocols like IP addressing and routing, and models like the OSI model.
- Descriptions of static and dynamic routing, protocols like RIP, OSPF, EIGRP, and commands used to configure routers.
This document discusses networking devices and technologies used to connect local area networks (LANs) and wide area networks (WANs). It describes common physical layer components used in Ethernet LANs such as twisted pair cable, fiber optic cable, and connectors. It also discusses serial connection options and devices used for WAN connections including CSU/DSUs and their roles as data terminal equipment (DTE) and data circuit-terminating equipment (DCE).
The document provides information about the CCNA certification options and Cisco networking concepts including the OSI model. It can be used to study for the CCNA exam. There are two options to obtain the CCNA: pass a single exam or two exams. The document then explains the OSI model in detail including mnemonics to remember the layer names and summaries of what occurs at each layer of the OSI model to help understand how data flows through a network.
Cisco Packet Tracer is a network simulation program that allows students to experiment with network behavior. The document describes how to set up three example networks using Packet Tracer. It explains how to connect routers and PCs, assign IP addresses to devices, and configure routing protocols to allow communication between the networks. Setting up the example networks demonstrates how to build and test a multi-network topology in Packet Tracer.
The document provides information about CCNA training and certification. It discusses the topics covered in the CCNA exam, recommended training courses, study materials, exam format and structure. The CCNA certification tests knowledge of network fundamentals, switching, routing, WAN technologies, security and management. Exams last 90 minutes and contain around 50-60 multiple choice and simulation questions. Common jobs requiring the CCNA include network administrator, database administrator and help desk technician.
A
PROJECT REPORT
On
CISCO CERTIFIED NETWORK ASSOCIATE
A computer network, or simply a network, is a collection of computer and other hardware components interconnected by communication channels that allow sharing of resources and information. Where at least one process in one device is able to send/receive data to/from at least one process residing in a remote device, then the two devices are said to be in a network. Simply, more than one computer interconnected through a communication medium for information interchange is called a computer network.
This document summarizes network devices and concepts from a CCNA guide. It describes how repeaters, hubs, wireless access points, bridges, switches and routers segment networks and control traffic. It also defines Ethernet, Fast Ethernet and Gigabit Ethernet standards, and explains half and full-duplex communication modes. The summary provides an overview of common network devices and technologies for local area networks.
CCNA Basic Switching and Switch ConfigurationDsunte Wilson
Â
This document provides an overview of basic switching concepts and Cisco switch configuration. It explains Ethernet and how switches work to segment networks and reduce collisions. Switches operate at the data link layer and learn MAC addresses to forward frames efficiently. The document discusses switch configuration using commands like hostname, interface, duplex, and port security. It compares switching methods like store-and-forward and cut-through forwarding. The summary reiterates how switches divide collision domains to improve performance over shared-medium Ethernet.
ccna summer training ppt ( Cisco certified network analysis) ppt. by Traun k...Tarun Khaneja
Â
This document provides a summary of a presentation on CCNA (Cisco Certified Network Associate). It was trained by Ravinder Kumar from Gurukul Technical Institute and submitted by Tarun Khaneja with roll number 2110045 and contact number 09034406598. The presentation introduces CCNA and discusses networking types and applications. It also covers networking devices, subnetting, routing protocols like RIP, EIGRP, OSPF, ACLs, VLANs, and inter-VLAN routing. Configuration examples are provided for EIGRP and RIP routing on the same network.
This document provides information about Cisco and the CCNA certification. It discusses Cisco as a company and their networking products. The CCNA certification focuses on routing, switching, security, service provider, and voice communication skills. The CCNA exam contains questions in drag and drop and simulation formats. The document also summarizes different types of computer networks, common networking devices, cable types, topologies and more.
This document discusses power aware routing protocols for wireless sensor networks. It begins by describing wireless sensor networks and how they are used to monitor environmental conditions. It then classifies routing protocols for sensor networks based on their functioning, node participation style, and network structure. Specific examples are provided for different types of routing protocols, including LEACH, TEEN, APTEEN, SPIN, Rumor Routing, and PEGASIS. Chain-based and clustering routing protocols are also summarized.
This document discusses wireless sensor networks and their role in the Internet of Things. It defines sensor networks and their architecture, including sensor nodes that communicate wirelessly to a base station. It outlines challenges for sensor networks like fault tolerance, scalability, and quality of service. It also describes how sensor networks can be integrated into the Internet of Things through different approaches, with the first using a single gateway and later approaches using hybrid networks and access points. Applications of sensor networks in IoT include wearable devices collecting biometric data and communicating it to servers.
In this webinar, we cover how Border Gateway Protocol works. Starting from key concepts, you'll learn about Autonomous Systems, the BGP protocol, AS Path, learning and advertising routes, RIBs and route selection. See the webinar recording at https://www.thousandeyes.com/webinars/how-bgp-works
This document provides steps for deploying Cisco Identity Services Engine (ISE) to enable 802.1X authentication on wired and wireless networks. It involves deploying ISE as the centralized RADIUS server, enabling MAC authentication bypass and 802.1X open mode on switches to monitor device connections in "monitor mode", integrating ISE with wireless LAN controllers for 802.1X wireless authentication, and profiling devices using DHCP and other traffic sources. The deployment is intended to enable identity-based network access without impacting existing connectivity as part of a phased approach to a full TrustSec deployment.
The document provides an overview of chapter 1 from the CCNA Routing and Switching Introduction to Networks course. It discusses how networks are used in everyday life and how they have changed the way people interact, learn, work and play. It also describes the basic components of networks, including end devices, intermediary devices, network media, and topologies. Additionally, it differentiates between local area networks (LANs), which span a small geographic area, and wide area networks (WANs), which interconnect LANs over a wider geographical area.
The document provides an overview of IEEE 802.11 standards for wireless local area networks. It discusses the creation of 802.11 by IEEE, the physical layer, frame formats, and various 802.11 protocols including 802.11b, 802.11a, 802.11g, 802.11n, and 802.11ac. It also describes the media access control including CSMA/CA and security features like authentication and WEP encryption.
CCNA 1 Routing and Switching v5.0 Chapter 1Nil Menon
Â
This document summarizes key points from Chapter 1 of a Cisco networking textbook. It introduces networking concepts like LANs, WANs and the Internet. It discusses how networks are used in daily life for communication, work and entertainment. It also outlines trends that will impact networks, such as BYOD, online collaboration, video and cloud computing. The chapter objectives are to explain network topologies, devices and characteristics used in small to medium businesses.
Advanced computer network lab manual (practicals in Cisco Packet tracer)VrundaBhavsar
Â
Book include how we can execute practical in cisco packet tracer.There are around 18 experiment covered .It contains topology also information about basic elements hub router.how we established
connection using HTTP and FTP protocols Also transferring Gmail and VOIP (Voice over IP) experiment. DHCP experiment included. How we create subnetmask.
Difference between OSI Layer & TCP/IP LayerNetwax Lab
Â
Difference between OSI Layer & TCP/IP Layer
TCP/IP OSI
It has 4 layers. It has 7 layers.
TCP/IP Protocols are considered to be standards
around which the internet has developed.
OSI Model however is a "generic, protocolindependent standard."
Follows Vertical Approach Follows Horizontal Approach
In TCP/IP Model, Transport Layer does not
Guarantees delivery of packets.
In OSI Model, Transport Layer Guarantees
delivery of packets.
This document discusses network models and addressing in computer networks. It describes the OSI 7-layer model and its layers from physical to application layer. It also discusses the TCP/IP protocol suite and how it maps to the OSI model. Finally, it covers the different types of addressing used in networks, including physical, logical, port, and specific addresses.
The document discusses various network architectures including Token Ring, Ethernet, FDDI, AppleTalk, ARCNET, and MAN systems. Token Ring uses a logical ring topology and token passing for data transfer. It has advantages like no data collisions but disadvantages if links are malfunctioning. Ethernet uses CSMA/CD and can use any physical topology. FDDI provides high performance over fiber optic cables in a token ring architecture. AppleTalk was an early client-server system for Macintosh. ARCNET uses token passing over coaxial cable and supports up to 255 nodes. MAN connects different LANs over large distances.
CCNA ppt designed on project remote connectivity using frame relay, and many more... best for project purpose. anyone want project will also contact me..
Overview of IPv6 protocol along with various transition scenarios for the migration from IPv4 to IPv6
IPv6 is the current and future Internet Protocol standard. As anticipated, IPv4 addresses became exhausted around 2012.
The IP address scarcity is the main driver for IPv6 protocol adoption.
IPv6 defines a much larger address space that should be sufficient for the foreseeable future, even taking into account Internet of Things scenarios with zillions of small devices connected to the Internet.
IPv6 is, however, much more than simply an expansion of the address space. IPv6 defines a clean address architecture with globally aggregatable addresses thus reducing routing table sizes in Internet routers.
IPv6 extension headers provide a standard mechanism for stacking protocols such as IP, IPSec, routing headers and upper layer headers such as TCP.
ICMP (Internet Control Message Protocol) is already defined for IPv4. ICMP was totally revamped for IPv6 and as ICMPv6 provides common functions like IP address and prefix assignment.
Lack of business drivers for migrating to IPv6 is responsible for sluggish adoption of IPv6 in carrier and enterprise networks.
Numerous transition mechanisms were developed to ease the transition from IPv4 to IPv6. Many of these mechanisms are complex and difficult to administer.
The transition mechanisms can be coarsely classified into dual-stack, tunneling and translation mechanisms.
CCNA is associate level career certification. It is an International certification course. Which is helpful to improve your career path in networking field. It gives lot of opportunity for Engineers and lots of opportunity having lots of job.
But now in these days,
This International course is offered by SMS Institute of Technology, Lucknow
So ,
There is no need to go anywhere for the training on CCNA Course Certification during summer Training.
I want to give this information because lots of people think about this course. But they have no any other way like - going to the training institute that offers CCNA Training But they give the certification on Own training Institute That is invalid Because CCNA is a International course Certification and these certificate are come on the email Id.
But Now this course Certification offers by SMS Institute of Technology But the certificate are valid through out the world.
Learn more at blog : --
https://solutionbyexpert.blogspot.com/2020/08/become-expert-secret-of-success-ii.html
#coding
#coding development skill program
#java
ARP is a protocol that maps IP addresses to MAC addresses. It works by broadcasting an ARP request packet to all devices on the local network segment. The device with the matching IP address responds with its MAC address, allowing the requesting device to send packets directly to the destination MAC address on the local network.
Wireless local area networks (WLANs) allow for mobility by using radio frequency or infrared communications instead of cables to connect devices to a network. Common WLAN standards include 802.11a, 802.11b, 802.11g, and 802.11n. WLANs use technologies like direct sequence spread spectrum, frequency hopping spread spectrum, and orthogonal frequency-division multiplexing. The 802.11 architecture defines the physical layer, data link layer including logical link control and media access control, and network topologies like peer-to-peer, access point based, and point-to-multipoint.
Wireless Sensor Network (WSN) consists of sensor nodes which interact with each other through physical parameters like sunlight, wind, vibration, humidity etc. Routing protocols provide an optimal data transmission route from sensor nodes to sink node to save energy of nodes. From Base Station (BS) Sensor node sends and receives data to or from wireless stations. Clustering mechanism is one of the popular routing mechanisms used in WSN for optimizing the problem in sensor nodes. There are two types of clustering schemes known as homogeneous schemes and heterogeneous schemes. In Homogeneous scheme initial energy is same for each node but in heterogeneous scheme initial energy is different for each node and also used to determine the efficiency of sensor networks. Enhanced Modified LEACH (EMODLEACH) is a reactive protocol which is implemented for homogeneous network model. We have implemented the concept of Efficient Cluster head Replacement scheme and Dual transmitting power level scheme of MODLEACH along with the concept of Efficient Intra Cluster transmission Scheme of TEEN in LEACH. We analyze the PEGASIS protocol and modified the exiting protocol called improved energy balanced routing protocol (IEBRP).This IEBRP is based on cluster formation, cluster routing and other aspects of LEACH protocol.
This chapter discusses subnetting, VLSM, and troubleshooting IP addressing. It covers subnetting basics like reducing network traffic and optimizing performance. The key points are:
1) Subnetting involves using some bits from the host portion of an IP address to create subnets. Subnet masks define which bits are used.
2) Class C subnetting allows for up to 4 subnets with a maximum of 62 hosts per subnet using a 255.255.255.192 subnet mask.
3) VLSM (Variable Length Subnet Masking) allows for subnets of different sizes, improving address utilization. Troubleshooting examines why hosts can't communicate and valid IP addresses.
This chapter discusses layer-2 switching and the Spanning Tree Protocol. Layer-2 switching provides hardware-based bridging to break up collision domains and learn hosts' locations via MAC tables, but can cause switching loops without STP. STP solves switching loops by selecting a root bridge and designating ports to block or forward traffic, putting ports into blocking, listening, forwarding, or disabled states.
CCNA Basic Switching and Switch ConfigurationDsunte Wilson
Â
This document provides an overview of basic switching concepts and Cisco switch configuration. It explains Ethernet and how switches work to segment networks and reduce collisions. Switches operate at the data link layer and learn MAC addresses to forward frames efficiently. The document discusses switch configuration using commands like hostname, interface, duplex, and port security. It compares switching methods like store-and-forward and cut-through forwarding. The summary reiterates how switches divide collision domains to improve performance over shared-medium Ethernet.
ccna summer training ppt ( Cisco certified network analysis) ppt. by Traun k...Tarun Khaneja
Â
This document provides a summary of a presentation on CCNA (Cisco Certified Network Associate). It was trained by Ravinder Kumar from Gurukul Technical Institute and submitted by Tarun Khaneja with roll number 2110045 and contact number 09034406598. The presentation introduces CCNA and discusses networking types and applications. It also covers networking devices, subnetting, routing protocols like RIP, EIGRP, OSPF, ACLs, VLANs, and inter-VLAN routing. Configuration examples are provided for EIGRP and RIP routing on the same network.
This document provides information about Cisco and the CCNA certification. It discusses Cisco as a company and their networking products. The CCNA certification focuses on routing, switching, security, service provider, and voice communication skills. The CCNA exam contains questions in drag and drop and simulation formats. The document also summarizes different types of computer networks, common networking devices, cable types, topologies and more.
This document discusses power aware routing protocols for wireless sensor networks. It begins by describing wireless sensor networks and how they are used to monitor environmental conditions. It then classifies routing protocols for sensor networks based on their functioning, node participation style, and network structure. Specific examples are provided for different types of routing protocols, including LEACH, TEEN, APTEEN, SPIN, Rumor Routing, and PEGASIS. Chain-based and clustering routing protocols are also summarized.
This document discusses wireless sensor networks and their role in the Internet of Things. It defines sensor networks and their architecture, including sensor nodes that communicate wirelessly to a base station. It outlines challenges for sensor networks like fault tolerance, scalability, and quality of service. It also describes how sensor networks can be integrated into the Internet of Things through different approaches, with the first using a single gateway and later approaches using hybrid networks and access points. Applications of sensor networks in IoT include wearable devices collecting biometric data and communicating it to servers.
In this webinar, we cover how Border Gateway Protocol works. Starting from key concepts, you'll learn about Autonomous Systems, the BGP protocol, AS Path, learning and advertising routes, RIBs and route selection. See the webinar recording at https://www.thousandeyes.com/webinars/how-bgp-works
This document provides steps for deploying Cisco Identity Services Engine (ISE) to enable 802.1X authentication on wired and wireless networks. It involves deploying ISE as the centralized RADIUS server, enabling MAC authentication bypass and 802.1X open mode on switches to monitor device connections in "monitor mode", integrating ISE with wireless LAN controllers for 802.1X wireless authentication, and profiling devices using DHCP and other traffic sources. The deployment is intended to enable identity-based network access without impacting existing connectivity as part of a phased approach to a full TrustSec deployment.
The document provides an overview of chapter 1 from the CCNA Routing and Switching Introduction to Networks course. It discusses how networks are used in everyday life and how they have changed the way people interact, learn, work and play. It also describes the basic components of networks, including end devices, intermediary devices, network media, and topologies. Additionally, it differentiates between local area networks (LANs), which span a small geographic area, and wide area networks (WANs), which interconnect LANs over a wider geographical area.
The document provides an overview of IEEE 802.11 standards for wireless local area networks. It discusses the creation of 802.11 by IEEE, the physical layer, frame formats, and various 802.11 protocols including 802.11b, 802.11a, 802.11g, 802.11n, and 802.11ac. It also describes the media access control including CSMA/CA and security features like authentication and WEP encryption.
CCNA 1 Routing and Switching v5.0 Chapter 1Nil Menon
Â
This document summarizes key points from Chapter 1 of a Cisco networking textbook. It introduces networking concepts like LANs, WANs and the Internet. It discusses how networks are used in daily life for communication, work and entertainment. It also outlines trends that will impact networks, such as BYOD, online collaboration, video and cloud computing. The chapter objectives are to explain network topologies, devices and characteristics used in small to medium businesses.
Advanced computer network lab manual (practicals in Cisco Packet tracer)VrundaBhavsar
Â
Book include how we can execute practical in cisco packet tracer.There are around 18 experiment covered .It contains topology also information about basic elements hub router.how we established
connection using HTTP and FTP protocols Also transferring Gmail and VOIP (Voice over IP) experiment. DHCP experiment included. How we create subnetmask.
Difference between OSI Layer & TCP/IP LayerNetwax Lab
Â
Difference between OSI Layer & TCP/IP Layer
TCP/IP OSI
It has 4 layers. It has 7 layers.
TCP/IP Protocols are considered to be standards
around which the internet has developed.
OSI Model however is a "generic, protocolindependent standard."
Follows Vertical Approach Follows Horizontal Approach
In TCP/IP Model, Transport Layer does not
Guarantees delivery of packets.
In OSI Model, Transport Layer Guarantees
delivery of packets.
This document discusses network models and addressing in computer networks. It describes the OSI 7-layer model and its layers from physical to application layer. It also discusses the TCP/IP protocol suite and how it maps to the OSI model. Finally, it covers the different types of addressing used in networks, including physical, logical, port, and specific addresses.
The document discusses various network architectures including Token Ring, Ethernet, FDDI, AppleTalk, ARCNET, and MAN systems. Token Ring uses a logical ring topology and token passing for data transfer. It has advantages like no data collisions but disadvantages if links are malfunctioning. Ethernet uses CSMA/CD and can use any physical topology. FDDI provides high performance over fiber optic cables in a token ring architecture. AppleTalk was an early client-server system for Macintosh. ARCNET uses token passing over coaxial cable and supports up to 255 nodes. MAN connects different LANs over large distances.
CCNA ppt designed on project remote connectivity using frame relay, and many more... best for project purpose. anyone want project will also contact me..
Overview of IPv6 protocol along with various transition scenarios for the migration from IPv4 to IPv6
IPv6 is the current and future Internet Protocol standard. As anticipated, IPv4 addresses became exhausted around 2012.
The IP address scarcity is the main driver for IPv6 protocol adoption.
IPv6 defines a much larger address space that should be sufficient for the foreseeable future, even taking into account Internet of Things scenarios with zillions of small devices connected to the Internet.
IPv6 is, however, much more than simply an expansion of the address space. IPv6 defines a clean address architecture with globally aggregatable addresses thus reducing routing table sizes in Internet routers.
IPv6 extension headers provide a standard mechanism for stacking protocols such as IP, IPSec, routing headers and upper layer headers such as TCP.
ICMP (Internet Control Message Protocol) is already defined for IPv4. ICMP was totally revamped for IPv6 and as ICMPv6 provides common functions like IP address and prefix assignment.
Lack of business drivers for migrating to IPv6 is responsible for sluggish adoption of IPv6 in carrier and enterprise networks.
Numerous transition mechanisms were developed to ease the transition from IPv4 to IPv6. Many of these mechanisms are complex and difficult to administer.
The transition mechanisms can be coarsely classified into dual-stack, tunneling and translation mechanisms.
CCNA is associate level career certification. It is an International certification course. Which is helpful to improve your career path in networking field. It gives lot of opportunity for Engineers and lots of opportunity having lots of job.
But now in these days,
This International course is offered by SMS Institute of Technology, Lucknow
So ,
There is no need to go anywhere for the training on CCNA Course Certification during summer Training.
I want to give this information because lots of people think about this course. But they have no any other way like - going to the training institute that offers CCNA Training But they give the certification on Own training Institute That is invalid Because CCNA is a International course Certification and these certificate are come on the email Id.
But Now this course Certification offers by SMS Institute of Technology But the certificate are valid through out the world.
Learn more at blog : --
https://solutionbyexpert.blogspot.com/2020/08/become-expert-secret-of-success-ii.html
#coding
#coding development skill program
#java
ARP is a protocol that maps IP addresses to MAC addresses. It works by broadcasting an ARP request packet to all devices on the local network segment. The device with the matching IP address responds with its MAC address, allowing the requesting device to send packets directly to the destination MAC address on the local network.
Wireless local area networks (WLANs) allow for mobility by using radio frequency or infrared communications instead of cables to connect devices to a network. Common WLAN standards include 802.11a, 802.11b, 802.11g, and 802.11n. WLANs use technologies like direct sequence spread spectrum, frequency hopping spread spectrum, and orthogonal frequency-division multiplexing. The 802.11 architecture defines the physical layer, data link layer including logical link control and media access control, and network topologies like peer-to-peer, access point based, and point-to-multipoint.
Wireless Sensor Network (WSN) consists of sensor nodes which interact with each other through physical parameters like sunlight, wind, vibration, humidity etc. Routing protocols provide an optimal data transmission route from sensor nodes to sink node to save energy of nodes. From Base Station (BS) Sensor node sends and receives data to or from wireless stations. Clustering mechanism is one of the popular routing mechanisms used in WSN for optimizing the problem in sensor nodes. There are two types of clustering schemes known as homogeneous schemes and heterogeneous schemes. In Homogeneous scheme initial energy is same for each node but in heterogeneous scheme initial energy is different for each node and also used to determine the efficiency of sensor networks. Enhanced Modified LEACH (EMODLEACH) is a reactive protocol which is implemented for homogeneous network model. We have implemented the concept of Efficient Cluster head Replacement scheme and Dual transmitting power level scheme of MODLEACH along with the concept of Efficient Intra Cluster transmission Scheme of TEEN in LEACH. We analyze the PEGASIS protocol and modified the exiting protocol called improved energy balanced routing protocol (IEBRP).This IEBRP is based on cluster formation, cluster routing and other aspects of LEACH protocol.
This chapter discusses subnetting, VLSM, and troubleshooting IP addressing. It covers subnetting basics like reducing network traffic and optimizing performance. The key points are:
1) Subnetting involves using some bits from the host portion of an IP address to create subnets. Subnet masks define which bits are used.
2) Class C subnetting allows for up to 4 subnets with a maximum of 62 hosts per subnet using a 255.255.255.192 subnet mask.
3) VLSM (Variable Length Subnet Masking) allows for subnets of different sizes, improving address utilization. Troubleshooting examines why hosts can't communicate and valid IP addresses.
This chapter discusses layer-2 switching and the Spanning Tree Protocol. Layer-2 switching provides hardware-based bridging to break up collision domains and learn hosts' locations via MAC tables, but can cause switching loops without STP. STP solves switching loops by selecting a root bridge and designating ports to block or forward traffic, putting ports into blocking, listening, forwarding, or disabled states.
The document provides an overview of networking concepts including:
- The OSI model which divides network communication into 7 layers and describes the function of each layer.
- Ethernet networking standards including half and full duplex modes and different cable types.
- Data encapsulation which involves adding protocol information at each OSI layer as data moves through a network.
- Cisco's three layer model which divides networks into core, distribution, and access layers.
This document provides reviews from Amazon readers praising Todd Lammle's CCNA study guide. Several reviews note that the study guide was their only resource for passing the CCNA exam. Readers comment that Todd explains complex topics in an easy-to-understand way and provides helpful review questions, exercises, and sample tests. The comprehensive study guide effectively prepares readers for the CCNA exam.
This document provides an overview of Cisco's IOS and the Cisco Switch and Desktop Monitor (SDM). It discusses connecting to Cisco routers, the boot-up process, command-line interface modes, configuration modes, editing features, administrative functions like hostnames, banners, passwords, and interface descriptions. It also covers bringing up and configuring interfaces, viewing and saving configurations, and verification tools.
CODE BLUE 2014 : Physical [In]Security: It’s not ALL about Cyber by Inbar RazCODE BLUE
Â
Today's threat landscape is all about Cyber. We have cyber threats, cyber security, cyber warfare, cyber intelligence, cyber espionage... Cyber is a synonym for the Internet, but sometimes, it's not -all- about the internet. Focusing defences on the Internet front leads to some wrong assumptions and the overlooking of much simpler, yet just-as-dangerous attack vectors.
This document provides an overview and introduction to a 3-day Perl development course. It discusses the goals of the course which are to familiarize students with the Perl language, different styles of Perl development, and commonly used Perl modules. It also provides a brief history of Perl and compares it to other programming languages like Python and Ruby.
This document discusses layered network models, specifically the OSI model and TCP/IP model. It provides an overview of each layer in both models and their functions. The key points are:
- The OSI model defines 7 layers that break communication into smaller parts to simplify the process and allow different hardware/software to work together.
- The TCP/IP model has 4 layers - application, transport, internet, and network access. It is used widely on the internet.
- Each layer adds header information to data as it moves down the stack. This encapsulation allows communication between layers and across networks.
The document discusses various topics for managing a Cisco internetwork including Cisco router components, the boot sequence, configuration registers, backing up and restoring the IOS and configuration, Cisco Discovery Protocol, Telnet, resolving hostnames, and troubleshooting tools. It provides details on these topics such as how to back up and restore configurations and software, use CDP to view neighbor information, set Telnet passwords, build a host table or use DNS for name resolution, and check network connectivity.
Module 10: Configuring and Troubleshooting Network File and Print Services
File and print services are some of the most commonly implemented network services for end users. Unlike infrastructure services like DNS, file and print services are highly visible to the end users. In this module, you will learn how to configure and troubleshoot file and print services to provide high quality service to end users. In addition, you will see how both EFS and BitLocker can be used to increase the security of files that are located in file shares.
Lessons
Configuring and Troubleshooting File Shares
Encrypting Network Files with EFS
Encrypting Partitions with BitLocker
Configuring and Troubleshooting Network Printing
Lab : Configuring and Troubleshooting Network File and Print Services
Creating and Configuring a File Share
Encrypting and Recovering Files
Creating and Configuring a Printer Pool
After completing this module, students will be able to:
Describe how to manage file share security.
Explain how to encrypt network files with EFS.
Describe how to encrypt partitions with BitLocker.
Discuss how to configure and troubleshoot network printing.
Introduction:
In the fast-evolving digital age of the 21st century, cybersecurity has emerged as a paramount concern for governments, businesses, and individuals. The Workshop on Cybersecurity is a comprehensive and immersive event designed to address the challenges posed by cyber threats and equip participants with the knowledge and tools to safeguard their digital assets. This workshop, to be held over five days, seeks to empower attendees with the latest insights and practices in cyber defense, fostering a culture of resilience and proactive security measures.
Day 1: Understanding the Cyber Landscape
The workshop commences with a deep dive into the complex cyber landscape that defines modern society. Distinguished experts from the cybersecurity field will present an overview of the ever-changing cyber ecosystem, highlighting its interconnectedness and vulnerabilities. Participants will gain valuable insights into the roles of governments, corporations, and individuals in shaping the cyber landscape.
Key topics covered will include the global impact of cyberattacks, the importance of international collaboration in countering cyber threats, and the significance of public-private partnerships. This foundational knowledge will serve as the basis for the subsequent discussions on cyber defense strategies.
Day 2: Unraveling Cyber Threats and Attack Vectors
Day two focuses on understanding the multitude of cyber threats and attack vectors that can target individuals and organizations. Renowned cybersecurity researchers will present real-life case studies of recent cyber incidents, ranging from nation-state-sponsored attacks to financially motivated hacking campaigns. Participants will gain a comprehensive understanding of the tactics employed by threat actors and the motivations behind their actions.
Through interactive sessions, attendees will be immersed in simulated cyber-attack scenarios, enabling them to identify and mitigate potential threats effectively. The day will emphasize the need for a proactive and adaptive approach to cybersecurity, as well as the importance of threat intelligence sharing to bolster collective defense capabilities.
Day 3: Building Robust Cyber Defense Strategies
Day three delves into the development and implementation of robust cyber defense strategies. Experts in the field will introduce participants to cutting-edge tools and technologies that can effectively detect, prevent, and respond to cyber threats. Topics covered will include advanced threat hunting techniques, next-generation firewalls, intrusion detection systems, and incident response best practices.
Participants will engage in practical workshops, enabling them to apply the newly acquired knowledge and skills to real-world scenarios. Emphasis will be placed on the importance of continuous monitoring, vulnerability management, and the establishment of an agile security infrastructure capable of adapting to emerging
This chapter discusses network security concepts like types of attacks, mitigation techniques, and access control lists. Standard access lists filter based on source IP addresses while extended lists can filter on additional attributes like destination address, protocol, and port numbers. Access lists are applied to router interfaces to permit or deny traffic and help implement security policies. The document provides examples of how to configure standard and extended access lists on Cisco routers to control network access.
How US pharmaceutical Market behaved during 2008.Why it has behaved like this what it depicts about the future. What the future hold?????????
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The document provides an agenda for a 2-day Advanced Cardiovascular Life Support (ACLS) course presented by Critical Concepts Corp. The course covers topics like secondary assessment, cardiopulmonary resuscitation (CPR), pulseless arrest, bradycardia, tachycardia, acute coronary syndrome, and stroke. Participants are divided into groups and rotate through learning stations, tests, and scenario-based practice sessions over the 2 days.
Open Shortest Path First (OSPF) is an interior gateway protocol that uses link state routing and the Dijkstra algorithm to calculate the shortest path to destinations within an autonomous system. It elects a Designated Router to generate network link advertisements and assist in database synchronization between routers. Routers run the Shortest Path First algorithm on their link state databases to determine the best routes and populate their routing tables.
CSE 2016 Future of Cyber Security by Matthew RosenquistMatthew Rosenquist
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Cybersecurity is a difficult and serious endeavor which over time strives to find a balance in managing the security of computing capabilities to protect the technology which connects and enriches the lives of everyone. Peering into the future of cybersecurity provides valuable insights around the challenges and opportunities. The industry is changing rapidly and attackers seem to always be one step ahead.
Presented by Matthew Rosenquist at the 2016 Connected Security Expo (CSE) @ ISC West http://www.connectedsecurityexpo.com/
The document provides a vision for cyber security in 2021, including emerging technologies, threats, and practices. It predicts that technologies like mobile computing, quantum computing, cloud computing, predictive semantics, and dynamic networks will impact cyber security. Threats will become more sophisticated through cyber warfare, crime, and activism. Cyber security practice will evolve to be more multi-dimensional and holistic through practices like cyber architecture and lifecycle management. A new lexicon for cyber security terms is also envisioned.
Circuit switching directly connects the sender and receiver through a dedicated physical path. Message switching transmits entire messages from node to node without establishing a dedicated path. Packet switching breaks messages into packets that can take different routes to the destination and are reassembled, allowing for more efficient use of bandwidth but introducing complexity.
This document provides an overview of the infrastructure used for Aerohive networking hands-on labs:
- Students connect wirelessly to Aerohive access points from their laptops to perform configuration exercises.
- Access points connect via Ethernet cables to Aerohive switches, which provide PoE and support VLAN trunking.
- A firewall with routing supports NAT, multiple virtual routers, and virtual clients for testing configurations.
- A console server allows SSH access to access point serial consoles for troubleshooting.
CCNA 1 Routing and Switching v5.0 Chapter 5Nil Menon
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This document provides an overview of Ethernet networking concepts including:
- How Ethernet frames are encapsulated and the purpose of the MAC sublayers.
- How MAC addresses are assigned and their role in end-to-end communication.
- The purpose and process of ARP for resolving IP addresses to MAC addresses.
- Basic functions of network switches including building the MAC address table and frame forwarding methods like cut-through switching.
CCNA-Security Official Exame Cetification GuideHussein Waly
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This document provides a summary of the CCNA Security Official Exam Certification Guide. It includes information about the authors, Michael Watkins and Kevin Wallace. It also acknowledges the technical reviewers, Ryan Lindfield and Anthony Sequeira. Finally, it includes dedications from each author to their families for supporting them through the writing process.
This document provides information about a study guide for the CWNA certification exam. It includes the front matter such as the title page, copyright information, and table of contents. The guide is published by Wiley Publishing and covers topics on wireless local area network administration related to the CWNA exam.
This document provides information about the production team involved in publishing the book, including the senior acquisitions editor, development editor, technical editor, production editor, copy editor, editorial manager, production manager, executive publisher, book designers, proofreader, indexer, project coordinator, and cover designer. It also includes acknowledgments for those involved, information about the author, and details regarding copyright and publishing.
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This document is the front matter and introduction to the OCA: Oracle Certified Associate Java SE 8 Programmer I Study Guide exam preparation book. It includes information about the authors Jeanne Boyarsky and Scott Selikoff, an acknowledgments section thanking contributors, and a brief description of the book's contents. The introduction serves to orient the reader to what they will find in the Oracle Java certification exam study guide.
Odom W. - Cisco CCNA Routing and Switching ICND2 200-101 Official Cert Guide ...Danar52
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This document provides information about the Cisco CCNA Routing and Switching ICND2 200-101 Official Cert Guide book. It includes the book title, author, publisher details, copyright information, and a warning and disclaimer. It also provides biographies of the author, contributing author, and technical reviewer who worked on the book. The document aims to provide readers with relevant details about the book and the expertise of those involved in creating it.
This document provides an overview of the CompTIA Server+ certification exam and exam preparation book. It includes information about the publisher, authors, editors, and technical reviewers for the book. The introduction also emphasizes the book's focus on providing only the essential information needed to prepare for the exam.
Routing and switching essentials companion guide
By Cisco Networking Academy
Published Feb 18, 2014 by Cisco Press. Part of the Companion Guide series.
Your ccna exam success strategy for routing and switchingVivek Tiwari
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This document provides information about a book titled "Your CCNA Exam Success Strategy: The Non-Technical Guide Book" written by Dean Bahizad and Vivek Tiwari, both of whom hold the CCIE certification. The book provides non-technical advice and strategies for passing the CCNA exam. It includes praise and reviews of the book from other IT professionals and details about the authors and their experience and credentials.
This document provides information about the CCNA Collaboration CICD 210-060 Official Cert Guide book. It includes the copyright information, publishing details, and biographies of the author and technical reviewers. The book is designed to help readers prepare for and pass the CCNA Collaboration CICD 210-060 exam, and provides an overview of Cisco unified communications technologies.
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This document provides an overview and summary of the PMP® Project Management Professional Exam Study Guide, Ninth Edition. It discusses the contents, contributors, acknowledgments, and author. The study guide is intended to help readers study and prepare for the PMP® exam based on the Project Management Body of Knowledge (PMBOK® Guide), Sixth Edition. It has been updated to match changes to the PMBOK® Guide.
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This document is the study guide for the Certified Ethical Hacker Version 9 exam. It includes an introduction from the author and acknowledgments. The study guide will help readers learn about ethical hacking methodologies, tools, and techniques to prepare for and pass the CEH exam. It covers topics like footprinting, scanning, enumeration, system hacking, malware, sniffers, social engineering, denial of service attacks, session hijacking, web servers and applications, and more.
This document is the official study guide for the (ISC)2 CISSP certification exam. It was written by Mike Chapple, James Michael Stewart, and Darril Gibson, and published by Wiley. The study guide is intended to help readers prepare for the CISSP exam by reviewing the eight domains of the CISSP Common Body of Knowledge, which are security and risk management, asset security, security architecture and engineering, communication and network security, identity and access management, security assessment and testing, security operations, and software development security.
This document contains 15 reviews from Amazon readers praising Todd Lammle's book for helping them pass the CCNA exam. Many reviewers note that the book clearly explains complex topics and provides practice questions, labs, and sample tests to help readers learn and prepare for the exam. Several reviewers state that the book was their only resource for studying and that they passed the CCNA on their first attempt after thoroughly reading the book. Overall, the reviews consistently highlight that Lammle's book is an excellent resource for learning networking concepts and preparing for the CCNA certification.
This document is the copyright and publishing information page for the book "PHP 5 For Dummies" by Janet Valade. It details the copyright of the book, owned by Wiley Publishing, and disclaims any warranties or guarantees about the accuracy of the book's content. It also acknowledges the author and those who helped publish and produce the book.
CCNA Security 640-554 official cert guide (Keith Barker Scott Morris).pdfkrcdnsqxswifzizvzs
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This document provides information about the CCNA Security 640-554 Official Cert Guide book. It includes the book title, authors, copyright information, publisher details, and an introduction. The authors are Keith Barker and Scott Morris, both holding CCIE certifications. The book is published by Cisco Press and is intended to help readers prepare for the CCNA Security 640-554 exam. It provides readers with information to help them pass the exam and earn the CCNA Security certification.
This document provides an overview and table of contents for the book "Kali Linux Cookbook" which contains over 70 recipes for effectively using Kali Linux, a Linux distribution for penetration testing. The book covers topics such as installing Kali Linux, customizing it, setting up an advanced testing lab, information gathering, vulnerability assessment, exploiting vulnerabilities, escalating privileges, password attacks, and wireless attacks. It is intended to help security professionals and novices master Kali Linux for penetration testing purposes.
This document provides information about a book titled "Microsoft® SQL ServerTM 2005 Programming For Dummies®" including details about the publisher, copyright information, and table of contents. The document discusses that the book was published by Wiley Publishing to provide guidance on SQL Server 2005 programming and covers topics such as retrieving and manipulating data, creating databases and database objects, programming security, and more advanced programming techniques.
AWS Certified SysOps Administrator Official Study Guide.pdfClaudia Acosta
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This document is the study guide for the AWS Certified SysOps Administrator - Associate exam. It was written by Stephen Cole, Gareth Digby, Christopher Fitch, Steve Friedberg, Shaun Qualheim, Jerry Rhoads, Michael Roth, and Blaine Sundrud. The study guide covers topics like compute services, networking, storage systems, databases, application deployment and management, monitoring and metrics, and high availability on AWS. It is intended to help readers prepare for and pass the AWS Certified SysOps Administrator - Associate certification exam.
- The document is the fifth edition of the companion guide for the Cisco Networking Academy course IT Essentials: PC Hardware and Software.
- It was published by Cisco Press and contains information about the authors, copyright details, and safety warnings and disclaimers.
- The book contains chapters covering topics like computer assembly, operating systems, networks, security, and troubleshooting, with the goal of providing information to support the IT Essentials course.
This document provides an overview of AutoCAD's Visual Basic for Applications (VBA) environment for customizing AutoCAD. It discusses what makes up an AutoCAD VBA project, what is needed to get started with VBA in AutoCAD, and how to determine if the VBA environment is installed. The document also acknowledges those involved in the development and production of the book.
Driving Business Innovation: Latest Generative AI Advancements & Success StorySafe Software
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Are you ready to revolutionize how you handle data? Join us for a webinar where we’ll bring you up to speed with the latest advancements in Generative AI technology and discover how leveraging FME with tools from giants like Google Gemini, Amazon, and Microsoft OpenAI can supercharge your workflow efficiency.
During the hour, we’ll take you through:
Guest Speaker Segment with Hannah Barrington: Dive into the world of dynamic real estate marketing with Hannah, the Marketing Manager at Workspace Group. Hear firsthand how their team generates engaging descriptions for thousands of office units by integrating diverse data sources—from PDF floorplans to web pages—using FME transformers, like OpenAIVisionConnector and AnthropicVisionConnector. This use case will show you how GenAI can streamline content creation for marketing across the board.
Ollama Use Case: Learn how Scenario Specialist Dmitri Bagh has utilized Ollama within FME to input data, create custom models, and enhance security protocols. This segment will include demos to illustrate the full capabilities of FME in AI-driven processes.
Custom AI Models: Discover how to leverage FME to build personalized AI models using your data. Whether it’s populating a model with local data for added security or integrating public AI tools, find out how FME facilitates a versatile and secure approach to AI.
We’ll wrap up with a live Q&A session where you can engage with our experts on your specific use cases, and learn more about optimizing your data workflows with AI.
This webinar is ideal for professionals seeking to harness the power of AI within their data management systems while ensuring high levels of customization and security. Whether you're a novice or an expert, gain actionable insights and strategies to elevate your data processes. Join us to see how FME and AI can revolutionize how you work with data!
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
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Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und ĂĽberflĂĽssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
Ivanti’s Patch Tuesday breakdown goes beyond patching your applications and brings you the intelligence and guidance needed to prioritize where to focus your attention first. Catch early analysis on our Ivanti blog, then join industry expert Chris Goettl for the Patch Tuesday Webinar Event. There we’ll do a deep dive into each of the bulletins and give guidance on the risks associated with the newly-identified vulnerabilities.
Salesforce Integration for Bonterra Impact Management (fka Social Solutions A...Jeffrey Haguewood
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Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on integration of Salesforce with Bonterra Impact Management.
Interested in deploying an integration with Salesforce for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
Programming Foundation Models with DSPy - Meetup SlidesZilliz
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Prompting language models is hard, while programming language models is easy. In this talk, I will discuss the state-of-the-art framework DSPy for programming foundation models with its powerful optimizers and runtime constraint system.
Main news related to the CCS TSI 2023 (2023/1695)Jakub Marek
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An English 🇬🇧 translation of a presentation to the speech I gave about the main changes brought by CCS TSI 2023 at the biggest Czech conference on Communications and signalling systems on Railways, which was held in Clarion Hotel Olomouc from 7th to 9th November 2023 (konferenceszt.cz). Attended by around 500 participants and 200 on-line followers.
The original Czech 🇨🇿 version of the presentation can be found here: https://www.slideshare.net/slideshow/hlavni-novinky-souvisejici-s-ccs-tsi-2023-2023-1695/269688092 .
The videorecording (in Czech) from the presentation is available here: https://youtu.be/WzjJWm4IyPk?si=SImb06tuXGb30BEH .
“Temporal Event Neural Networks: A More Efficient Alternative to the Transfor...Edge AI and Vision Alliance
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For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/temporal-event-neural-networks-a-more-efficient-alternative-to-the-transformer-a-presentation-from-brainchip/
Chris Jones, Director of Product Management at BrainChip , presents the “Temporal Event Neural Networks: A More Efficient Alternative to the Transformer” tutorial at the May 2024 Embedded Vision Summit.
The expansion of AI services necessitates enhanced computational capabilities on edge devices. Temporal Event Neural Networks (TENNs), developed by BrainChip, represent a novel and highly efficient state-space network. TENNs demonstrate exceptional proficiency in handling multi-dimensional streaming data, facilitating advancements in object detection, action recognition, speech enhancement and language model/sequence generation. Through the utilization of polynomial-based continuous convolutions, TENNs streamline models, expedite training processes and significantly diminish memory requirements, achieving notable reductions of up to 50x in parameters and 5,000x in energy consumption compared to prevailing methodologies like transformers.
Integration with BrainChip’s Akida neuromorphic hardware IP further enhances TENNs’ capabilities, enabling the realization of highly capable, portable and passively cooled edge devices. This presentation delves into the technical innovations underlying TENNs, presents real-world benchmarks, and elucidates how this cutting-edge approach is positioned to revolutionize edge AI across diverse applications.
TrustArc Webinar - 2024 Global Privacy SurveyTrustArc
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How does your privacy program stack up against your peers? What challenges are privacy teams tackling and prioritizing in 2024?
In the fifth annual Global Privacy Benchmarks Survey, we asked over 1,800 global privacy professionals and business executives to share their perspectives on the current state of privacy inside and outside of their organizations. This year’s report focused on emerging areas of importance for privacy and compliance professionals, including considerations and implications of Artificial Intelligence (AI) technologies, building brand trust, and different approaches for achieving higher privacy competence scores.
See how organizational priorities and strategic approaches to data security and privacy are evolving around the globe.
This webinar will review:
- The top 10 privacy insights from the fifth annual Global Privacy Benchmarks Survey
- The top challenges for privacy leaders, practitioners, and organizations in 2024
- Key themes to consider in developing and maintaining your privacy program
How to Interpret Trends in the Kalyan Rajdhani Mix Chart.pdfChart Kalyan
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A Mix Chart displays historical data of numbers in a graphical or tabular form. The Kalyan Rajdhani Mix Chart specifically shows the results of a sequence of numbers over different periods.
Have you ever been confused by the myriad of choices offered by AWS for hosting a website or an API?
Lambda, Elastic Beanstalk, Lightsail, Amplify, S3 (and more!) can each host websites + APIs. But which one should we choose?
Which one is cheapest? Which one is fastest? Which one will scale to meet our needs?
Join me in this session as we dive into each AWS hosting service to determine which one is best for your scenario and explain why!
5th LF Energy Power Grid Model Meet-up SlidesDanBrown980551
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5th Power Grid Model Meet-up
It is with great pleasure that we extend to you an invitation to the 5th Power Grid Model Meet-up, scheduled for 6th June 2024. This event will adopt a hybrid format, allowing participants to join us either through an online Mircosoft Teams session or in person at TU/e located at Den Dolech 2, Eindhoven, Netherlands. The meet-up will be hosted by Eindhoven University of Technology (TU/e), a research university specializing in engineering science & technology.
Power Grid Model
The global energy transition is placing new and unprecedented demands on Distribution System Operators (DSOs). Alongside upgrades to grid capacity, processes such as digitization, capacity optimization, and congestion management are becoming vital for delivering reliable services.
Power Grid Model is an open source project from Linux Foundation Energy and provides a calculation engine that is increasingly essential for DSOs. It offers a standards-based foundation enabling real-time power systems analysis, simulations of electrical power grids, and sophisticated what-if analysis. In addition, it enables in-depth studies and analysis of the electrical power grid’s behavior and performance. This comprehensive model incorporates essential factors such as power generation capacity, electrical losses, voltage levels, power flows, and system stability.
Power Grid Model is currently being applied in a wide variety of use cases, including grid planning, expansion, reliability, and congestion studies. It can also help in analyzing the impact of renewable energy integration, assessing the effects of disturbances or faults, and developing strategies for grid control and optimization.
What to expect
For the upcoming meetup we are organizing, we have an exciting lineup of activities planned:
-Insightful presentations covering two practical applications of the Power Grid Model.
-An update on the latest advancements in Power Grid -Model technology during the first and second quarters of 2024.
-An interactive brainstorming session to discuss and propose new feature requests.
-An opportunity to connect with fellow Power Grid Model enthusiasts and users.
Digital Banking in the Cloud: How Citizens Bank Unlocked Their MainframePrecisely
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Inconsistent user experience and siloed data, high costs, and changing customer expectations – Citizens Bank was experiencing these challenges while it was attempting to deliver a superior digital banking experience for its clients. Its core banking applications run on the mainframe and Citizens was using legacy utilities to get the critical mainframe data to feed customer-facing channels, like call centers, web, and mobile. Ultimately, this led to higher operating costs (MIPS), delayed response times, and longer time to market.
Ever-changing customer expectations demand more modern digital experiences, and the bank needed to find a solution that could provide real-time data to its customer channels with low latency and operating costs. Join this session to learn how Citizens is leveraging Precisely to replicate mainframe data to its customer channels and deliver on their “modern digital bank” experiences.
In the realm of cybersecurity, offensive security practices act as a critical shield. By simulating real-world attacks in a controlled environment, these techniques expose vulnerabilities before malicious actors can exploit them. This proactive approach allows manufacturers to identify and fix weaknesses, significantly enhancing system security.
This presentation delves into the development of a system designed to mimic Galileo's Open Service signal using software-defined radio (SDR) technology. We'll begin with a foundational overview of both Global Navigation Satellite Systems (GNSS) and the intricacies of digital signal processing.
The presentation culminates in a live demonstration. We'll showcase the manipulation of Galileo's Open Service pilot signal, simulating an attack on various software and hardware systems. This practical demonstration serves to highlight the potential consequences of unaddressed vulnerabilities, emphasizing the importance of offensive security practices in safeguarding critical infrastructure.
Digital Marketing Trends in 2024 | Guide for Staying AheadWask
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https://www.wask.co/ebooks/digital-marketing-trends-in-2024
Feeling lost in the digital marketing whirlwind of 2024? Technology is changing, consumer habits are evolving, and staying ahead of the curve feels like a never-ending pursuit. This e-book is your compass. Dive into actionable insights to handle the complexities of modern marketing. From hyper-personalization to the power of user-generated content, learn how to build long-term relationships with your audience and unlock the secrets to success in the ever-shifting digital landscape.
Let's Integrate MuleSoft RPA, COMPOSER, APM with AWS IDP along with Slackshyamraj55
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Discover the seamless integration of RPA (Robotic Process Automation), COMPOSER, and APM with AWS IDP enhanced with Slack notifications. Explore how these technologies converge to streamline workflows, optimize performance, and ensure secure access, all while leveraging the power of AWS IDP and real-time communication via Slack notifications.
5. Dear Reader,
Thank you for choosing CCNA Routing and Switching Review Guide. This book is part of a family of
premium-quality Sybex books, all of which are written by outstanding authors who combine practical
experience with a gift for teaching.
Sybex was founded in 1976. More than 30 years later, we’re still committed to producing con-sistently
exceptional books. With each of our titles, we’re working hard to set a new standard for the industry.
From the paper we print on to the authors we work with, our goal is to bring you the best books
available.
I hope you see all that reflected in these pages. I’d be very interested to hear your comments and get
your feedback on how we’re doing. Feel free to let me know what you think about this or any other
Sybex book by sending me an email at contactus@sybex.com. If you think you’ve found a technical
error in this book, please visit http://sybex.custhelp.com. Customer feed-back is critical to our efforts at
Sybex.
Best regards,
Chris Webb
Associate Publisher
Sybex, an Imprint of Wiley
6. Acknowledgments
First, a loud callout to Jim Frye, who was instrumental in putting this book together. He spent
countless hours combining and summarizing my work from the CCENT and CCNA ICND2 study
guides into what is a really nice review guide for the CCNA Routing and Switching certification.
Thank you, Jim!
Thanks to Jeff Kellum, who always keeps me working hard and makes sure I am headed in the
right direction. This is no easy task for Jeff!
And thanks to my production editor, Eric Charbonneau, for keeping the book on track, and Amy
Breguet, for keeping all the edits in order and on time. And I can’t forget Judy Flynn, the backbone
of all my books, who reads every word over and over until the chapters are nearly flawless!
Last, thanks to Isaac Valdez, my tech editor for this edition of the review guide. Thank
you all!
7. About the Author
Todd Lammle is the authority on Cisco certification and internetworking and is Cisco certi-fied
in most Cisco certification categories. He is a world-renowned author, speaker, trainer, and
consultant. Todd has three decades of experience working with LANs, WANs, and large enterprise
licensed and unlicensed wireless networks, and lately he’s been implementing large Cisco data
centers worldwide. His years of real-world experience is evident in his writing; he is not just an
author but an experienced networking engineer with very practical experience working on the
largest networks in the world at such companies as Xerox, Hughes Aircraft, Texaco, AAA, Cisco,
and Toshiba, among many others. Todd has published over 60 books, including the very popular
CCNA: Cisco Certified Network Associate Study Guide, CCNA Wireless Study Guide, and CCNA
Data Center Study Guides, all from Sybex. He runs an international consulting and training
company based in Colorado, Texas, and San Francisco.
You can reach Todd through his forum and blog at www.lammle.com.
About the Contributor
Jim Frye has over 20 years of experience in the computing field and holds numerous IT
industry certifications in computing and networking. Jim is employed with GlobalNet Training
and Consulting, Inc., a network integration and training firm based in Colorado, Texas, and San
Francisco. His technical expertise is a great value and asset to GlobalNet.
8. Contents at a Glance
Introduction xvii
Chapter 1 Operation of IP Data Networks 1
Chapter 2 LAN Switching Technologies 55
Chapter 3 IP Addressing (IPv4 / IPv6) 135
Chapter 4 IP Routing Technologies 163
Chapter 5 IP Services 265
Chapter 6 Network Device Security 307
Chapter 7 Troubleshooting 341
Chapter 8 WAN Technologies 439
Appendix A Answers to Review Questions 473
Appendix B About the Additional Study Tools 483
Index 487
9. Contents
Introduction xvii
Chapter 1 Operation of IP Data Networks 1
Operation of IP Data Networks 2
Exam Essentials 3
Recognize the Purpose and Functions of Various Network
Devices Such as Routers, Switches, Bridges, and Hubs 3
Exam Essentials 6
Select the Components Required to Meet a Given
Network Specification 7
Exam Essentials 9
Identify Common Applications and Their Impact
on the Network 9
Exam Essentials 18
Describe the Purpose and Basic Operation of the Protocols
in the OSI and TCP/IP Models 18
The Layered Approach 18
Advantages of Reference Models 19
The OSI Reference Model 19
Exam Essentials 32
Predict the Data Flow between Two Hosts across a Network 33
The IP Routing Process 35
Exam Essentials 41
Identify the Appropriate Media, Cables, Ports, and Connectors
to Connect Cisco Network Devices to Other Network Devices
and Hosts in a LAN 42
Ethernet Cabling 43
Fiber Optic 49
Exam Essentials 50
Review Questions 51
Chapter 2 LAN Switching Technologies 55
Determine the Technology and Media Access Control
Method for Ethernet Networks 57
CSMA/CD 57
Half- and Full-Duplex Ethernet 59
Exam Essentials 61
Identify Basic Switching Concepts and the Operation
of Cisco Switches 61
Collision Domains 61
Broadcast Domains 63
10. viii Contents
Types of Switching 64
CAM Table 64
Exam Essentials 67
Configure and Verify Initial Switch Configuration Including
Remote Access Management 68
Cisco IOS Commands to Perform Basic Switch Setup 68
Entering the CLI 69
Overview of IOS Modes 69
CLI Prompts 70
Editing and Help Features 72
Administrative Configurations 77
Exam Essentials 87
Verify Network Status and Switch Operation Using Basic
Utilities Such as Ping, Telnet, and SSH 89
ping Command 89
traceroute Command 90
Debugging 91
show processes Command 93
Exam Essentials 94
Identify Enhanced Switching Technologies 94
RSTP 94
PVSTP 97
Etherchannels 98
Exam Essentials 100
Describe How VLANs Create Logically Separate Networks
and the Need for Routing between Them 100
Broadcast Control 102
Explain Network Segmentation and Basic Traffic
Management Concepts 103
Frame Tagging 104
VLAN Identification Methods 106
Exam Essentials 107
Configure and Verify VLANs 107
Assigning Switch Ports to VLANs 110
Exam Essentials 112
Configure and Verify Trunking
on Cisco Switches 112
Defining the Allowed VLANs on a Trunk 114
Changing or Modifying the Trunk Native VLAN 115
DTP 116
Auto Negotiation 116
Exam Essentials 118
11. Contents ix
Configure and Verify PVSTP Operation 118
Describe Root Bridge Election 124
Spanning Tree Mode 130
Exam Essentials 131
Review Questions 132
Chapter 3 IP Addressing (IPv4 / IPv6) 135
Describe the Operation and Necessity of Using Private and
Public IP Addresses for IPv4 Addressing 136
IP Terminology 136
The Hierarchical IP Addressing Scheme 137
Private IP Addresses (RFC 1918) 142
IPv4 Address Types 143
Exam Essentials 143
Identify the Appropriate IPv6 Addressing Scheme
to Satisfy Addressing Requirements in a
LAN/WAN Environment 143
Shortened Expression 144
Exam Essentials 145
Identify the Appropriate IPv4 Addressing Scheme Using
VLSM and Summarization to Satisfy Addressing
Requirements in a LAN/WAN Environment 145
VLSM Design 147
Implementing VLSM Networks 147
Exam Essentials 148
Describe the Technological Requirements for Running IPv6
in Conjunction with IPv4 Such as Dual Stack 150
Dual Stacking (ISATAP) 152
6to4 Tunneling 153
IPv6 Routing 154
Exam Essentials 156
Describe IPv6 Addresses 156
Global Unicast 156
Multicast 157
Link Local 157
Unique Local 157
eui 64 157
autoconfiguration 159
Exam Essentials 160
Review Questions 161
12. x Contents
Chapter 4 IP Routing Technologies 163
Describe Basic Routing Concepts 166
Packet Forwarding 168
Router Lookup Process 169
Exam Essentials 169
Describe the Boot Process of Cisco IOS Routers 169
POST 170
Router Bootup Process 170
Exam Essentials 170
Configure and Verify Utilizing the CLI to Set Basic
Router Configuration 171
Entering the CLI 171
Overview of Router Modes 171
CLI Prompts 172
Cisco IOS Commands to Perform Basic Router Setup 174
Encrypting Your Passwords 182
Descriptions 184
Exam Essentials 185
Configure and Verify Operation Status of a Device Interface,
Both Serial and Ethernet 186
Bringing Up an Interface 189
Exam Essentials 194
Verify Router Configuration and Network Connectivity 195
Cisco IOS Commands to Review Basic Router Information
and Network Connectivity 195
Exam Essentials 205
Configure and Verify Routing Configuration for a Static or
Default Route Given Specific Routing Requirements 205
Static Routing 206
Default Routing 207
Exam Essentials 208
Manage Cisco IOS Files 208
Boot Preferences 209
Cisco IOS Image(s) 215
Licensing 220
Exam Essentials 226
Differentiate Methods of Routing and Routing Protocols 227
Static vs. Dynamic 227
Link State vs. Distance Vector 228
Administrative Distance 228
Split Horizon 229
Metric 229
Next Hop 229
13. Contents xi
IP Routing Table 230
Passive Interfaces 230
Exam Essentials 230
Configure and Verify OSPF (Single Area) 231
Benefit of Single Area 235
Neighbor Adjacencies 235
OSPF States 236
Discuss Multi Area 238
Configure OSPF v2 238
Configure OSPF v3 243
Router ID 244
Passive Interface 245
LSA Types 245
Exam Essentials 246
Configure and Verify EIGRP (Single AS) 246
Feasible Distance / Feasible Successors /
Administrative Distance 250
Feasibility Condition 250
Metric Composition 250
Router ID 251
Auto Summary 251
Path Selection 251
Load Balancing 252
Passive Interface 253
Exam Essentials 253
Configure and Verify InterVLAN Routing (Router on a Stick) 254
Sub Interfaces 258
Upstream Routing 258
Encapsulation 259
Exam Essentials 260
Configure SVI Interfaces 260
Exam Essentials 261
Review Questions 262
Chapter 5 IP Services 265
Configure and Verify DHCP (IOS Router) 267
Configuring Router Interfaces to Use DHCP 268
DHCP Options 268
Excluded Addresses 269
Lease Time 269
Exam Essentials 269
14. xii Contents
Describe the Types, Features, and Applications of ACLs 269
Standard 270
Extended 271
Named 271
Numbered 271
Log Option 272
Exam Essentials 272
Configure and Verify ACLs in a Network Environment 272
Named 273
Log Option 274
Exam Essentials 275
Identify the Basic Operation of NAT 276
Purpose 276
Pool 277
Static 277
1 to 1 278
Overloading 278
Source Addressing 278
One Way NAT 279
Exam Essentials 280
Configure and Verify NAT for Given Network Requirements 280
Static NAT Configuration 280
Dynamic NAT Configuration 281
PAT (Overloading) Configuration 282
Simple Verification of NAT 282
Exam Essentials 283
Configure and Verify NTP as a Client 285
Exam Essentials 286
Recognize High Availability (FHRP) 287
VRRP 289
HSRP 289
GLBP 293
Exam Essentials 296
Configure and Verify Syslog 296
Utilize Syslog Output 298
Exam Essentials 301
Describe SNMP v2 & v3 301
Exam Essentials 303
Review Questions 304
Chapter 6 Network Device Security 307
Configure and Verify Network Device Security Features 309
Device Password Security 309
Enable Secret vs. Enable Password 309
15. Contents xiii
Transport 311
Disable Telnet 311
SSH 311
VTYs 313
Physical Security 314
Service Password 314
Describe External Authentication Methods 315
Exam Essentials 316
Configure and Verify Switch Port Security Features 316
Sticky MAC 318
MAC Address Limitation 318
Static/Dynamic 319
Violation Modes 319
Protect Restrict 320
Shutdown Unused Ports 320
Err Disable Recovery 320
Assign Unused Ports to an Unused VLAN 321
Setting Native VLAN to Other than VLAN 1 321
Exam Essentials 321
Configure and Verify ACLs to Filter Network Traffic 322
Exam Essentials 335
Configure and Verify ACLs to Limit Telnet and SSH Access
to the Router 335
Exam Essentials 336
Review Questions 337
Chapter 7 Troubleshooting 341
Identify and Correct Common Network Problems 344
Exam Essentials 355
Utilize Netflow Data 355
Exam Essentials 357
Troubleshoot and Correct Common Problems Associated
with IP Addressing and Host Configurations 358
Exam Essentials 361
Troubleshoot and Resolve VLAN Problems 362
Identify That VLANs Are Configured 362
Port Membership Correct 363
IP Address Configured 364
Exam Essentials 364
Troubleshoot and Resolve Trunking Problems on
Cisco Switches 365
Correct Trunk States 365
Correct Encapsulation Configured 366
Correct VLANs Allowed 367
Exam Essentials 367
16. xiv Contents
Troubleshoot and Resolve Spanning Tree Operation Issues 368
Root Switch 368
Priority 369
Mode Is Correct 370
Port States 370
Exam Essentials 370
Troubleshoot and Resolve Routing Issues 371
Routing Is Enabled 371
Routing Table Is Correct 372
Correct Path Selection 372
Exam Essentials 374
Troubleshoot and Resolve OSPF Problems 374
Neighbor Adjacencies 378
Hello and Dead Timers 378
OSPF Area 378
Interface MTU 380
Network Types 380
Exam Essentials 381
Troubleshoot and Resolve EIGRP Problems 381
Neighbor Adjacencies 386
AS Number 388
Load Balancing 389
Split Horizon 391
Exam Essentials 393
Troubleshoot and Resolve InterVLAN Routing Problems 393
Connectivity 393
Encapsulation 398
Subnet 399
Native VLAN 400
Port Mode Trunk Status 400
Exam Essentials 402
Troubleshoot and Resolve ACL Issues 402
Statistics 404
Permitted Networks 404
Direction 405
Exam Essentials 405
Troubleshoot and Resolve WAN Implementation Issues 405
Serial Interfaces 407
PPP 407
Frame Relay 411
Exam Essentials 418
Troubleshoot and Resolve Layer 1 Problems 418
Verifying Your Network 418
Verifying Your Interfaces 420
17. Contents xv
Framing 425
CRC 425
Runts 425
Giants 425
Dropped Packets 425
Late Collision 425
Input / Output Errors 426
Verifying Interface Configuration 426
Exam Essentials 429
Monitor NetFlow Statistics 429
Exam Essentials 431
Troubleshoot EtherChannel Problems 431
Exam Essentials 434
Review Questions 435
Chapter 8 WAN Technologies 439
Identify Different WAN Technologies 440
Common WAN Protocols 441
VPN 443
Exam Essentials 444
Configure and Verify a Basic WAN Serial Connection 444
Exam Essentials 446
Configure and Verify a PPP Connection between
Cisco Routers 446
Configuring PPP on Cisco Routers 446
Configuring PPP Authentication 446
Verifying and Troubleshooting Serial Links 447
Exam Essentials 452
Configure and Verify Frame Relay on Cisco Routers 452
Frame Relay Bandwidth 453
Frame Relay Implementation and Monitoring 456
Troubleshooting Frame Relay Networks 463
Exam Essentials 467
Implement and Troubleshoot PPPoE 467
Exam Essentials 468
Review Questions 469
Appendix A Answers to Review Questions 473
Chapter 1: Operation of IP Data Networks 474
Chapter 2: LAN Switching Technologies 475
Chapter 3: IP Addressing (IPv4 / IPv6) 475
Chapter 4: IP Routing Technologies 476
Chapter 5: IP Services 477
18. xvi Contents
Chapter 6: Network Device Security 478
Chapter 7: Troubleshooting 479
Chapter 8: WAN Technologies 480
Appendix B About the Additional Study Tools 483
Additional Study Tools 484
Test Engine 484
Electronic Flashcards 484
PDF of Glossary of Terms 484
Adobe Reader 484
System Requirements 485
Using the Study Tools 485
Troubleshooting 485
Customer Care 486
Index 487
19. Introduction
Welcome to the exciting world of Cisco certification! If you’ve picked up this book because you
want to improve yourself and your life with a better, more satisfying and secure job, you’ve done
the right thing. Whether you’re striving to enter the thriving, dynamic IT sector or seeking to
enhance your skillset and advance your position within it, being Cisco certified can seriously stack
the odds in your favor to help you attain your goals!
Cisco certifications are powerful instruments of success that also markedly improve your grasp
of all things internetworking. As you progress through this book, you’ll gain a complete
understanding of networking that reaches far beyond Cisco devices. By the end of this book, you’ll
comprehensively know how disparate network topologies and technologies work together to form
the fully operational networks that are vital to today’s very way of life in the developed world. The
knowledge and expertise you’ll gain here is essential for and relevant to every networking job and
is why Cisco certifications are in such high demand— even at companies with few Cisco devices!
Although it’s now common knowledge that Cisco rules routing and switching, the fact that it
also rocks the voice, data center, and service provider world is also well recognized. And Cisco
certifications reach way beyond the popular but less extensive certifications like those offered by
CompTIA and Microsoft to equip you with indispensable insight into today’s vastly complex
networking realm. Essentially, by deciding to become Cisco certified, you’re proudly announcing
that you want to become an unrivaled networking expert—a goal that this book will get you well on
your way to achieving. Congratulations in advance to the beginning of your brilliant future!
For up-to-the-minute updates covering additions or modifications to the Cisco
certification exams, as well as additional study tools, review ques-tions, and
bonus material, be sure to visit the Todd Lammle websites and forum at
www.lammle.com, www.lammlesim.com, and www.lammle.com/forum.
Cisco’s Network Certifications
It used to be that to secure the holy grail of Cisco certifications—the CCIE—you passed only one
written test before being faced with a grueling, formidable hands-on lab. This intensely daunting,
all-or-nothing approach made it nearly impossible to succeed and predictably didn’t work out too
well for most people. Cisco responded to this issue by creating a series of new certifications, which
not only made it easier to eventually win the highly coveted CCIE prize, it gave employers a way to
accurately rate and measure the skill levels of prospective and cur-rent employees. This exciting
paradigm shift in Cisco’s certification path truly opened doors that few were allowed through
before!
20. xviii Introduction
Beginning in 1998, obtaining the Cisco Certified Network Associate (CCNA) certifica-tion was
the first milestone in the Cisco certification climb as well as the official prerequisite to each of the
more advanced levels. But that changed when Cisco announced the Cisco Certified Entry Network
Technician (CCENT) certification. And then in March 2013, Cisco once again proclaimed that all-
new CCENT and CCNA R/S tests will be required beginning in October of the same year; now the
Cisco certification process looks like Figure I.1.
F i g u r e I .1 The Cisco certification path
Cisco 2013 Certification Path Announcements
Routing/Switching
Data
Center Voice Security Wireless
CCIE CCIE CCIE CCIE CCIE
CCNP CCNP CCNP CCNP CCNP
CCNA CCNA CCNA CCNA CCNA
CCENT No Prerequisites CCENT CCENT CCENT
I have included only the most popular tracks in Figure I.1. In addition to the ones
in this image, there are also tracks for Design, Service Provider, Ser-vice
Provider Operations, and Video. Also note that the CCIE Voice certifi-cation
retirement will be announced shortly.
The Cisco Routing and Switching (R/S) path is by far the most popular and could very well
remain so, but soon you’ll see the Data Center path become more and more of a focus as
companies migrate to data center technologies. The Voice track also actually does pro-vide a good
job opportunity. Still, understanding the foundation of R/S before attempting any other
certification track is something I highly recommend.
Even so, and as the figure shows, you only need your CCENT certification to get under-way for
most of the tracks. Also, note that there are a few other certification tracks you can go down that
are not shown in the figure, although they’re not as popular as the ones shown. You can find
information on all Cisco certification tracks at www.cisco.com.
Cisco Certified Entry Network Technician (CCENT)
Don’t be fooled by the oh-so-misleading name of this first certification because it absolutely isn’t
entry level! Okay—maybe entry level for Cisco’s certification path, but definitely not for
22. Intr oducti on xix
job market! For the uninitiated, the CompTIA A+ and Network+ certifications aren’t official
prerequisites, but know that Cisco does expect you to have that type and level of experience before
embarking on your Cisco certification journey.
All of this gets us to 2013, when the climb to Cisco supremacy just got much harder again. The
innocuous-sounding siren’s call of the CCENT can lure you to some serious trouble if you’re not
prepared, because it’s actually much harder than the old CCNA ever was. This will rapidly become
apparent once you start studying, but be encouraged! The fact that the certification process is
getting harder really works better for you in the long run, because that which is harder to obtain
only becomes that much more valuable when you finally do, right? Yes, indeed!
Another important factor to keep in mind is that the CCENT 100-101 exam, which is one of
the exams this book was written for, costs $150 per attempt and it’s anything but easy to pass!
The good news is that this book will guide you step-by-step in building a strong foundation in
routing and switching technologies. You really need to build on a
strong technical foundation and stay away from exam cram type books, suspicious online material,
and the like. They can help somewhat, but understand that you’ll pass the Cisco certification exams
only if you have a strong foundation and that you’ll get that solid foun-dation only by reading as
much as you can, performing the written labs and review ques-tions in this book, and practicing lots
and lots of hands-on labs. Additional practice exam questions, videos, and labs are offered on my
website, and what seems like a million other sites offer additional material that can help you study.
However, there is one way to skip the CCENT exam and still meet the prerequisite required
before moving on to any other certification track, and that path is through the CCNA Routing and
Switching composite (CCNA R/S) exam. First, I’ll discuss the Interconnecting Cisco Network
Devices 2 (ICND2) exam and then tell you about the composite CCNA exam, which will provide
you, when successful, with both the CCENT and the CCNA R/S certification.
Cisco Certified Network Associate Routing
and Switching (CCNA R/S)
Once you have achieved your CCENT certification, you can take the ICND2 (200-101) exam in
order to achieve your CCNA R/S certification. This is now the most popular certi-fication Cisco
has by far because it’s the most sought-after certification of all employers.
As with the CCENT, this exam is also $150 per attempt—although thinking you can just skim a
book and pass any of these exams would probably be a really expensive mistake! The
CCENT/CCNA exams are extremely hard and cover a lot of material, so you have to really know
your stuff. Taking a Cisco class or spending months with hands-on experience is defi-nitely a
requirement to succeed when faced with this monster!
And once you have your CCNA, you don’t have to stop there—you can choose to continue and
achieve an even higher certification, called the Cisco Certified Network Professional (CCNP).
There are various ones, as shown in Figure I.1. The CCNP R/S is still the most popular, with Voice
certifications coming in at a close second. And I’ve got to tell you that the Data Center certification
will be catching up fast. Also good to know is that anyone with
23. xx Introduction
a CCNP R/S has all the skills and knowledge needed to attempt the notoriously dreaded but
coveted CCIE R/S lab. But just becoming a CCNA R/S can land you that job you’ve dreamed
about and that’s what this book is all about: helping you to get and keep a great job!
Still, why take two exams to get your CCNA if you don’t have to? Cisco still has the
composite exam called CCNA 200-120 that, if passed, will land you with your CCENT and
your CCNA R/S via only one test, priced accordingly at $300.
Why Become a CCENT and CCNA R/S?
Cisco, like Microsoft and other vendors that provide certification, has created the certifica-tion
process to give administrators a set of skills and to equip prospective employers with a way to
measure those skills or match certain criteria. And as you probably know, becoming a CCNA R/S
is certainly the initial, key step on a successful journey toward a new, highly rewarding, and
sustainable networking career.
The CCNA program was created to provide a solid introduction not only to the Cisco
Internetwork Operating System (IOS) and Cisco hardware but also to internetworking in general,
making it helpful to you in areas that are not exclusively Cisco’s. And regarding today’s
certification process, it’s not unrealistic that network managers—even those without Cisco
equipment—require Cisco certifications for their job applicants.
Rest assured that if you make it through the CCNA and are still interested in Cisco and
internetworking, you’re headed down a path to certain success!
What Skills Do You Need to Become a CCENT?
The CCENT exam tests a candidate for the knowledge and skills required to successfully install,
operate, and troubleshoot a small branch office network.
The exam includes questions on the operation of IP data networks, LAN switching
technologies, IPv6, IP routing technologies, IP services network device security, and basic
troubleshooting.
What Skills Do You Need to Become a CCNA R/S?
To be a CCNA R/S, you need to be able to successfully install, operate, and troubleshoot a small to
medium-size enterprise branch network. Topics include LAN switching technologies, IP routing
technologies, IP services (FHRP, syslog, SNMP v2 and v3), troubleshooting, and WAN
technologies.
To become a CCNA R/S, as mentioned earlier, you have two options: take and pass the ICND1
and ICND2 exams, or pass one little test, the CCNA Composite exam (200-120), and then—
poof!—you’re a CCNA R/S. Oh, but don’t you wish it were that easy? True, it’s just one test, but
it’s a whopper, and to pass it you must possess enough knowledge to under-stand what the test
writers are saying, and you need to know everything I mentioned previ-ously! Hey, it’s hard, but it
can be done!
24. Intr oducti on xxi
Candidates can prepare for the CCNA Composite exam by taking the Todd Lammle authorized
Cisco bootcamps. This composite exam tests that a candidate has the knowl-edge and skills
required to install, operate, and troubleshoot a small to medium-size enter-prise branch network.
The topics include all the areas covered under the 100-101 ICND1 and 200-101 ICND2 exams.
I can’t stress this point enough: It’s critical that you have some hands-on experience with Cisco
routers. If you can get ahold of some basic routers and switches, you’re set.
For Cisco certification hands-on training with CCSI Todd Lammle, please see
www.lammle.com. Each student will get hands-on experience by config-uring at
least three routers and two switches—no sharing of equipment!
How Is This Book Organized?
This book is organized according to the official objectives list prepared by Cisco for the CCNA
exams.
This book maps to the CCNA Composite (200-120) exam objectives, which is a
composite of the CCENT/ICND1 (100-101) and ICND2 (200-101) exam
objectives. Refer to the Cisco website (www.cisco.com/web/learning) for a
detailed list of the exam objectives.
Within each chapter, the individual exam objectives are addressed. Each section of a chapter
covers one exam objective. For each objective, the critical information is first pre-sented, and then
there are several Exam Essentials for each exam objective. Additionally, each chapter ends with a
section of review questions. Here is a closer look at each of these components:
Exam Objectives The individual exam objective sections present the greatest level of
detail on information that is relevant to the CCNA exams. This is the place to start if you’re
unfamiliar with or uncertain about the technical issues related to the objective.
Exam Essentials Here you are given a short list of topics that you should explore fully
before taking the exam. Included in the Exam Essentials areas are notations of the key
information you should take out of the corresponding exam objective section.
Review Questions At the end of every chapter there are 10 questions to help you gauge your
mastery of the material.
25. xxii Introduction
What’s Available Online?
I have worked hard to provide some really great tools to help you with your certification process.
All of the following tools, most of them available at www.sybex.com/go/ccnarsrg, should be loaded
on your workstation when you’re studying for the test:
Two CCNA Practice Exams Online, you will find the Sybex test engine, with two exclusive
CCNA bonus practice exams. Using this custom test engine, you can identify weak areas up front
and then develop a solid studying strategy using each of these robust testing features.
Our thorough readme file will walk you through the quick, easy installation process.
Electronic Flashcards The companion study tools include 100 flashcards specifically written
to hit you hard, so don’t get discouraged if you don’t ace your way through them at first! They’re
there to ensure that you’re really ready for the exam. And no worries— armed with the review
questions, practice exams, and flashcards, you’ll be more than prepared when exam day comes!
Glossary A complete glossary of CCENT, CCNA, and Cisco routing terms is available at
www.sybex.com/go/ccnarsrg.
Note that this book is designed to be a review of the exam topics and should be
used in tandem with other study materials, including my CCNA Routing and
Switching Study Guide (Sybex, 2013). The study guide includes a lot more
additional tools, including more practice exam questions, a bonus LammleSim
network simulator to provide hands-on experience, and samples from the Todd
Lammle Video Training Series.
Where Do You Take the Exams?
You may take the ICND1, ICND2, or CCNA R/S Composite exam at any Cisco exam at any of
the Pearson VUE authorized testing centers. For information, go to www.vue.com or call 877-404-
EXAM (3926).
To register for a Cisco exam, follow these steps:
1. Determine the number of the exam you want to take. (The CCENT exam number is 100-
101, ICND2 is 200-101, and CCNA R/S is 200-120.)
2. Register with the nearest Pearson VUE testing center. At this point, you will be asked to pay in
advance for the exam.. You can schedule exams up to six weeks in advance or as late as the
day you want to take it—but if you fail a Cisco exam, you must wait five days before you will
be allowed to retake it. If something comes up and you need to cancel or reschedule your exam
appointment, contact Pearson VUE at least 24 hours in advance.
26. Intr oducti on xxiii
3. When you schedule the exam, you’ll get instructions regarding all appointment and
cancellation procedures, the ID requirements, and information about the testing-center
location.
Tips for Taking Your Cisco Exams
The Cisco exams contains about 50 questions and must be completed in about 90 minutes or less
(the ICND2 exam is 75 minutes or less). This information can change per exam. You must get a
score of about 85 percent to pass this exam, but again, each exam can be different. Many questions
on the exam have answer choices that at first glance look identical— especially the syntax
questions! So remember to read through the choices carefully because close just doesn’t cut it. If
you get commands in the wrong order or forget one measly char-
acter, you’ll get the question wrong.
Also, never forget that the right answer is the Cisco answer. In many cases, more than one
appropriate answer is presented, but the correct answer is the one that Cisco recommends. On the
exam, you will always be told to pick one, two, or three options, never “choose all that apply.” The
Cisco exam may include the following test formats:
â– â–
Multiple-choice single answer
â– â–
Multiple-choice multiple answer
â– â–
Drag-and-drop
â– â–
Router simulations
Cisco proctored exams will not show the steps to follow in completing a router interface
configuration, but they do allow partial command responses. For example, show run or sho running
or sh running-config would be acceptable.
Here are some general tips for exam success:
â– â–
Arrive early at the exam center so you can relax and review your study materials.
â– â–
Read the questions carefully. Don’t jump to conclusions. Make sure you’re clear about
exactly what each question asks. “Read twice, answer once” is what I always tell my
students.
â– â–
When answering multiple-choice questions that you’re not sure about, use the process of
elimination to get rid of the obviously incorrect answers first. Doing this greatly improves
your odds if you need to make an educated guess.
â– â–
You can no longer move forward and backward through the Cisco exams, so double-check
your answer before clicking Next since you can’t change your mind.
After you complete an exam, you’ll get immediate, online notification of your pass or fail
status, a printed examination score report that indicates your pass or fail status, and your exam
results by section. (The test administrator will give you the printed score report.) Test scores are
automatically forwarded to Cisco within five working days after you take the test, so you don’t
need to send your score to them. If you pass the exam, you’ll receive confirma-tion from Cisco,
typically within two to four weeks, sometimes a bit longer.
27.
28. Chapter
1
Operation of IP
Data Networks
The Following CCNA Routing and
Switching Exam Objectives Are
Covered in This Chapter:
âś“âś“ Operation of IP Data Networks
âś“âś“ Recognize the purpose and functions of various network devices such as Routers, Switches,
Bridges and Hubs.
âś“âś“ Select the components required to meet a given network specification.
âś“âś“ Identify common applications and their impact on the network.
âś“âś“ Describe the purpose and basic operation of the protocols in the OSI and TCP/IP models.
âś“âś“ Predict the data flow between two hosts across a network.
âś“âś“ Identify the appropriate media, cables, ports, and connectors to connect Cisco network devices to
other network devices and hosts in a LAN.
29. In this chapter, I will review the basics of internetwork-ing and
what an internetwork is. I will go over some of the components
that make up a network as well as some appli-
cations used in networking. I will also go over the OSI and TCP/IP models and, finally, explain
how data flows across a network as well as discuss the various connectors used in a network.
Operation of IP Data Networks
Let’s start by defining exactly what an internetwork is: You create an internetwork when you
connect two or more networks via a router and configure a logical network addressing scheme
with a protocol such as IPv4 or IPv6.
Why is it so important to learn Cisco internetworking anyway? Networks and networking
have grown exponentially over the past 20 years, and understandably so. They’ve had to
evolve at light speed just to keep up with huge increases in basic,
mission-critical user needs (for example, simple sharing of data and printers) as well as greater
burdens like multimedia remote presentations and conferencing. Unless everyone who needs to
share network resources is located in the same office space—an increas-ingly uncommon
situation—the challenge is to connect relevant networks so all users can share the wealth of
whatever services and resources are required. Figure 1.1 shows a basic local area network (LAN)
that’s connected using a hub, which is basically just an antiquated device that connects wires
together. Keep in mind that a simple network like this would be considered one collision domain
and one broadcast domain.
F i g u r e 1.1 A very basic network
Hub
Bob HEY SALLY? Sally
30. Recognize the Purpose and Functions of Various Network Devices ........................3
Figure 1.1 illustrates this scenario: Bob wants to send Sally a file, and to complete that goal in
this kind of network, he’ll simply broadcast that he’s looking for her, which is basically just
shouting out over the network. As networks grow and get more complex, a good network design is
essential. Growth can be good, but growth can also hinder your network. LAN con-gestion can
bring your network to a halt! The solution to this is to break up a large network into smaller
networks, which is called network segmentation.
This concept is a lot like planning a new community or modernizing an existing one. More
streets are added, complete with new intersections and traffic signals, plus post offices with official
maps documenting all those street names and directions on how to get to each are built. You’ll
need to effect new laws to keep order to it all and provide a police station to protect this nice new
neighborhood as well. In a networking neighborhood environment, all of this is carried out using
devices like routers, switches, and bridges.
Exam Essentials
Understand what an internetwork is. An internetwork consists of two or more networks that
are connected together via a router. Networks are configured with a logical addressing schemes
and segmented into smaller networks using routers, switches, and bridges.
Recognize the Purpose and Functions
of Various Network Devices Such as
Routers, Switches, Bridges, and Hubs
The scenario I just described brings me to the basic point of what this book and the Cisco
certification objectives are really all about. My goal of showing you how to create efficient
networks and segment them correctly in order to minimize all the chaotic yell-ing and screaming
going on in them is a universal theme throughout my CCENT and CCNA series books. It’s just
inevitable that you’ll have to break up a large network into a bunch of smaller ones at some point
to match a network’s equally inevitable growth, and as that expansion occurs, user response time
simultaneously dwindles to a frustrat-ing crawl. But if you master the vital technology and skills I
have in store for you in this book, you’ll be well equipped to rescue your network and its users by
creating an efficient new network neighborhood to give them key amenities like the bandwidth
they need to meet their evolving demands.
And this is no joke; most of us think of growth as good—and it can be—but as many of us
experience daily when commuting to work, school, etc., it can also mean your LAN’s traffic
congestion can reach critical mass and grind to a complete halt!
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So let’s take a look at our new neighborhood now, because the word has gotten out; many more
hosts have moved into it, so it’s time to upgrade that new high-capacity infrastructure that we
promised to handle the increase in population. Figure 1.2 shows a network that’s been segmented
with a switch, making each network segment that connects to the switch its own separate collision
domain. Doing this results in a lot less yelling!
F i g u r e 1. 2 A switch can break up collision domains.
Hub Switch
S1
Bob Sally
HEY JOHN! John
This is still one single broadcast domain. You can see that the hub used in Figure 1.2 just
extended the one collision domain from the switch port. The result is that John received the data
from Bob but, happily, Sally did not. This is good because Bob intended to talk with John directly,
and if he had needed to send a broadcast instead, everyone, including Sally, would have received it,
possibly causing unnecessary congestion.
Here’s a list of some of the things that commonly cause LAN traffic congestion:
â– â–
Too many hosts in a collision or broadcast domain
â– â–
Broadcast storms
â– â–
Too much multicast traffic
â– â–
Low bandwidth
â– â–
Adding hubs for connectivity to the network
â– â–
A bunch of ARP broadcasts
Take another look at Figure 1.2 and make sure you see that I extended the main hub from
Figure 1.1 to a switch in Figure 1.2. I did that because hubs don’t segment a network; they just
connect network segments.
As a network begins to grow, routers are used to connect networks and route packets of data
from one network to another. Cisco became the de facto standard for routers because of its
unparalleled selection of high-quality router products and fantastic service. So never forget that by
default, routers are basically employed to efficiently break up a broadcast domain—the set of all
devices on a network segment, which are allowed to “hear” all broadcasts sent out on that specific
segment.
Figure 1.3 depicts a router in our growing network, creating an internetwork and breaking up
broadcast domains.
32. Recognize the Purpose and Functions of Various Network Devices ........................5
F i g u r e 1. 3 Routers create an internetwork.
S2 R1 S2
I LOVE SHOUTING! Sure is nice and quiet here.
. . . HEY EVERYONE!
Each host is connected to its own collision domain because of the switch, and the router has
created two broadcast domains. Routers also provide connections to wide area network (WAN)
services as well as via a serial interface for WAN connections—specifically, a V.35 physical
interface on a Cisco router.
Even though routers are known for breaking up broadcast domains by default, it’s important
to remember that they break up collision domains as well.
There are two advantages to using routers in your network:
â– â–
They don’t forward broadcasts by default.
â– â–
They can filter the network based on layer 3, Network layer, information such as an IP
address.
Here are four ways a router functions in your network:
â– â–
Packet switching
â– â–
Packet filtering
â– â–
Internetwork communication
â– â–
Path selection
It’s helpful to think of routers as layer 3 switches. Unlike layer 2 switches, which forward or
filter frames, routers (layer 3 switches) use logical addressing and provide an important capacity
called packet switching. Routers can also provide packet filtering
via access lists, and when routers connect two or more networks together and use logical addressing
(IPv4 or IPv6), you then have an internetwork. Finally, routers use a routing table, which is
essentially a map of the internetwork, to make best path selections for getting data to its proper
destination and properly forward packets to remote networks.
Conversely, we don’t use layer 2 switches to create internetworks because they don’t break up
broadcast domains by default. Instead, they’re employed to add functionality to a network LAN.
The main purpose of these switches is to make a LAN work better—to optimize its performance—
providing more bandwidth for the LAN’s users. Also, these switches don’t for-ward packets to
other networks like routers do. Instead, they only “switch” frames from one port to another within
the switched network.
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By default, switches break up collision domains, but what are these things? Collision domain is
an Ethernet term used to describe a network scenario in which one device sends a packet out on a
network segment and every other device on that same segment is forced to pay attention no matter
what. This isn’t very efficient because if a different device tries to transmit at the same time, a
collision will occur, requiring both devices to retransmit, one at a time—not good! This happens a
lot in a hub environment, where each host segment connects to a hub that represents only one
collision domain and a single broadcast domain. By contrast, each and every port on a switch
represents its own collision domain, allowing network traffic to flow much more smoothly.
Switches create separate collision domains within a single broadcast domain.
Routers provide a separate broadcast domain for each interface. Don’t let this
ever confuse you!
You’ll still hear Cisco and others refer to LAN switches as multiport bridges now and
then.
Basically, switches are multiport bridges with more brain power and more ports!
You would use a bridge in a network to reduce collisions within broadcast
domains and to increase the number of collision domains in your network. Doing
this provides more bandwidth for users. And never forget that using hubs in your
Ethernet network can contribute to congestion. As always, plan your network
design carefully!
Exam Essentials
Describe the difference between a collision domain and a broadcast domain. Collision
domain is an Ethernet term used to describe a network collection of devices in which one particular
device sends a packet on a network segment, forcing every other device on that same segment to
pay attention to it. With a broadcast domain, a set of all devices on a network hears all broadcasts
sent on all segments.
Understand the difference between a hub, a bridge/switch, and a router. All ports on a hub
are in one collision domain. When data is received on a port, it is sent out to all ports
simultaneously. Each port on a switch is a separate collision domain. When data is received on a
switchport, it is sent only to the receiving host that needs it. Routers are used to create
internetworks and provide connections to WAN services. Routers break up broadcast and collision
domains as well.
34. Select the Components Required to Meet a Given Network Specification 7
Select the Components Required to
Meet a Given Network Specification
The term bridging was introduced before routers and switches were implemented, so it’s pretty
common to hear people referring to switches as bridges. That’s because bridges and switches
basically do the same thing—break up collision domains on a LAN. Note to self that you cannot
buy a physical bridge these days, only LAN switches, which use bridging technologies. This
means that you’ll still hear Cisco and others refer to LAN switches as multiport bridges now and
then.
But does it mean that a switch is just a multiple-port bridge with more brainpower? Well, pretty
much, only there are still some key differences. Switches do provide a bridging function, but they
do that with greatly enhanced management ability and features. Plus, most bridges had only 2 or 4
ports, which is severely limiting. Of course, it was possible to get your hands on a bridge with up to
16 ports, but that’s nothing compared to the hundreds of ports avail-able on some switches!
Figure 1.4 shows how a network would look with various internetwork devices in place.
Remember, a router doesn’t just break up broadcast domains for every LAN interface; it breaks up
collision domains too.
Looking at Figure 1.4, did you notice that the router has the center stage position and
connects each physical network together? I’m stuck with using this layout because of the ancient
bridges and hubs involved. I really hope you don’t run across a network like this, but it’s still
really important to understand the strategic ideas that this figure represents!
See that bridge up at the top of the internetwork shown in Figure 1.4? It’s there to connect the
hubs to a router. The bridge breaks up collision domains, but all the hosts connected to both hubs
are still crammed into the same broadcast domain. That bridge also created only three collision
domains, one for each port, which means that each device connected to a hub is in the same
collision domain as every other device connected to that same hub. This is really lame and to be
avoided if possible, but it’s still better than having one collision domain for all hosts! So don’t do
this at home; it’s a great museum piece and a wonderful example of what not to do, but this
inefficient design would be terrible for use in today’s networks! It does show us how far we’ve
come though, and again, the foundational concepts it illustrates are really important for you to get.
The three interconnected hubs at the bottom of the figure also connect to the router. This setup
creates one collision domain and one broadcast domain and makes that bridged network, with its
two collision domains, look much better by contrast!
The best network connected to the router is the LAN switched network on the left. Why?
Because each port on that switch breaks up collision domains. But it’s not all good— all devices
are still in the same broadcast domain. This can be bad because all devices must listen to all
broadcasts transmitted. And if your broadcast domains are too large, the users have less bandwidth
and are required to process more broadcasts. Network response time eventually will slow to a level
that could cause your users to riot and strike, so it’s impor-tant to keep your broadcast domains
small in the vast majority of networks today.
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F i g u r e 1. 4 Internetworking devices
Hub
Bridge
Switch Router
WAN services
ISP
Figure 1.5 demonstrates a network you’ll typically stumble upon today.
LAN switches are at the center of this network, with the routers connecting the logical networks.
If I went ahead and implemented this design, I’ve created something called virtual LANs, or
VLANs, which are used when you logically break up broadcast domains in a layer 2 switched
network. It’s really important to understand that even in a switched network envi-ronment, you still
need a router to provide communication between VLANs.
F i g u r e 1. 5 Switched networks creating an internetwork
Router
36. Identify Common Applications and Their Impact on the Network 9
Still, clearly the best network design is the one that’s perfectly configured to meet the
business requirements of the specific company or client it serves, and it’s usually one in which
LAN switches exist in harmony with routers strategically placed in the network.
Let’s look at Figure 1.4 again. How many collision domains and broadcast domains are really
there in this internetwork?
The all-hub network at the bottom is one collision domain; the bridge network on top equals
three collision domains. Add in the switch network of five collision domains—one for each
switch port—and you get a total of nine!
In Figure 1.5, each port on the switch is a separate collision domain, and each VLAN would be
a separate broadcast domain. So how many collision domains do you see here? I’m counting 12—
remember that connections between the switches are considered a collision domain! Since the
figure doesn’t show any VLAN information, we can assume that the default of one VLAN, or one
broadcast domain, is in place.
Exam Essentials
Understand the importance of essential network design. Placing routers and switches in a
properly designed network configuration will fulfill the needs of a specific company or client and
will operate with optimal performance.
Identify the functions and advantages of routers. Routers perform packet switching, filter-
ing, and path selection, and they facilitate internetwork communication. One advantage of routers
is that they reduce broadcast traffic.
Identify Common Applications and Their
Impact on the Network
In this section, we’ll go over the different applications and services typically used in IP networks,
and although there are many more protocols defined here, we’ll focus on the protocols most
relevant to the CCNA objectives. Here’s a list of the protocols and appli-cations we’ll cover in
this section:
â– â–
Telnet
â– â–
SSH
â– â–
FTP
â– â–
TFTP
â– â–
SNMP
â– â–
HTTP
â– â–
HTTPS
37. 10 Chapter 1 â–
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â– â–
NTP
â– â–
DNS
â– â–
DHCP/BootP
Telnet
Telnet was one of the first Internet standards, developed in 1969, and is the chameleon of
protocols—its specialty is terminal emulation. It allows a user on a remote client machine, called
the Telnet client, to access the resources of another machine, the Telnet server, in order to access a
command-line interface. Telnet achieves this by pulling a fast one on the Telnet server and making
the client machine appear as though it were a terminal directly attached to the local network. This
projection is actually a software image—a virtual terminal that can interact with the chosen remote
host. A drawback is that there are no encryption techniques available within the Telnet protocol, so
everything must be sent in clear text, including pass-words! Figure 1.6 shows an example of a
Telnet client trying to connect to a Telnet server.
F i g u r e 1. 6 Telnet
>telnet 1.1.1.2
Can I have access to
your command line?
Okay! Configure me!
I’ll send everything in
clear text, including
passwords...
Good, because I can’t
do encryption!
These emulated terminals are of the text-mode type and can execute defined procedures such as
displaying menus that give users the opportunity to choose options and access the applications on
the duped server. Users begin a Telnet session by running the Telnet client software and then
logging into the Telnet server. Telnet uses an 8-bit, byte-oriented data connection over TCP,
which makes it very thorough. It’s still in use today because it is so simple and easy to use, with
very low overhead, but again, with everything sent in clear text, it’s not recommended in
production.
Secure Shell (SSH)
Secure Shell (SSH) protocol sets up a secure session that’s similar to Telnet over a standard TCP/IP
connection and is employed for doing things like logging into systems, running pro-grams on
remote systems, and moving files from one system to another. And it does all of this while
maintaining an encrypted connection. Figure 1.7 shows an SSH client trying to connect to an SSH
server. The client must send the data encrypted!
38. Identify Common Applications and Their Impact on the Network 11
F i g u r e 1.7 Secure Shell
>ssh admin@1.1.1.2
Can I have access to
your command line?
I accept only
encrypted data!
Here is my encrypted
username, password, and
key: a@#$alskdjf2H!Vm34
Here is my response:
eSgkh2g42#$!@!#!$kjka12s
You can think of it as the new-generation protocol that’s now used in place of the
antiquated and very unused rsh and rlogin—even Telnet.
File Transfer Protocol (FTP)
File Transfer Protocol (FTP) actually lets us transfer files, and it can accomplish this between any
two machines using it. But FTP isn’t just a protocol; it’s also a program. Operating as a protocol,
FTP is used by applications. As a program, it’s employed by users to perform file tasks by hand.
FTP also allows for access to both directories and files and can accomplish certain types of
directory operations, such as relocating into different ones (Figure 1.8).
But accessing a host through FTP is only the first step. Users must then be subjected to an
authentication login that’s usually secured with passwords and usernames implemented by system
administrators to restrict access. You can get around this somewhat by adopting the username
anonymous, but you’ll be limited in what you’ll be able to access.
F i g u r e 1. 8 FTP
>ftp@1.1.1.2
I want to get a file!
Which one?
I don’t know, what do
you have available?
No problem! Here is my
directory of available files!
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Even when employed by users manually as a program, FTP’s functions are limited to listing
and manipulating directories, typing file contents, and copying files between hosts. It can’t
execute remote files as programs.
Trivial File Transfer Protocol (TFTP)
Trivial File Transfer Protocol (TFTP) is the stripped-down, stock version of FTP, but it’s the
protocol of choice if you know exactly what you want and where to find it because it’s fast and so
easy to use!
But TFTP doesn’t offer the abundance of functions that FTP does because it has no
directory-browsing abilities, meaning that it can only send and receive files (Figure 1.9).
F i g u r e 1. 9 TFTP
tftp 10.1.1.2
I want to get a file!
I’m not smart enough to
know what that means!
What files do
you have?
I’m TFTP! I don’t
know!
Fine! Give me a specific file
from flash memory. Here is
the name of the file...
I can do that!
This compact little protocol also skimps in the data department, sending much smaller blocks
of data than FTP. Also, there’s no authentication as with FTP, so it’s even more insecure, and few
sites support it because of the inherent security risks.
Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP) collects and manipulates valuable network
information, as you can see in Figure 1.10. It gathers data by polling the devices on the net-work
from a network management station (NMS) at fixed or random intervals, requiring them to disclose
certain information, or even by asking for certain information from the device. In addition, network
devices can inform the NMS station about problems as they occur so the network administrator is
alerted.
When all is well, SNMP receives something called a baseline—a report delimiting the
operational traits of a healthy network. This protocol can also stand as a watchdog over the
network, quickly notifying managers of any sudden turn of events. These network watchdogs are
called agents, and when aberrations occur, agents send an alert called a trap to the management
station.
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since Microsoft supported HTTPS, it became the de facto standard for securing web com-
munication. But no matter—as indicated, it’s a secure version of HTTP that arms you with a whole
bunch of security tools for keeping transactions between a web browser and a server secure.
It’s what your browser needs to fill out forms, sign in, authenticate, and encrypt an HTTP
message when you do things online like make a reservation, access your bank account, or
buy something.
Network Time Protocol (NTP)
Kudos to professor David Mills of the University of Delaware for coming up with this handy
protocol that’s used to synchronize the clocks on our computers to one standard time source
(typically, an atomic clock). Network Time Protocol (NTP) works by syn-chronizing devices to
ensure that all computers on a given network agree on the time (Figure 1.12).
This may sound pretty simple, but it’s very important because so many of the transactions done
today are time and date stamped. Think about databases—a server can get messed up pretty badly
and even crash if it’s out of sync with the machines connected to it by even mere seconds! You
can’t have a transaction entered by a machine at, say, 1:50 a.m. when the server records that
transaction as having occurred at 1:45 a.m. So basically, NTP works to prevent a “back to the
future sans DeLorean” scenario from bringing down the network—very impor-tant indeed!
F i g u r e 1.12 NTP
NTP server
What is the exact time?
I have some errors to report
but I need to record them with
the correct time and date! I’m connected to an atomic
clock on the Internet—here
is the exact time and date!
Domain Name Service (DNS)
Domain Name Service (DNS) resolves hostnames—specifically, Internet names, such as
www.lammle.com. But you don’t have to actually use DNS. You just type in the IP address of any
device you want to communicate with and find the IP address of a URL by using the Ping program.
For example, >ping www.cisco.com will return the IP address resolved by DNS.
42. Identify Common Applications and Their Impact on the Network 15
An IP address identifies hosts on a network and the Internet as well, but DNS was designed to
make our lives easier. Think about this: What would happen if you wanted to move your web page
to a different service provider? The IP address would change and no one would know what the
new one was. DNS allows you to use a domain name to specify an IP address. You can change the
IP address as often as you want and no one will know the difference.
To resolve a DNS address from a host, you’d typically type in the URL from your favor-ite
browser, which would hand the data to the Application layer interface to be transmitted on the
network. The application would look up the DNS address and send a UDP request to your DNS
server to resolve the name (Figure 1.13).
F i g u r e 1.13 DNS
What is the address for I don’t know. Let me check
Lammle.com? with another server!
1 2
5
Get
Lammle.com is 4
m 198.1.78.115 DNS server
e
to
198.1
.
78.
115
ASAP!
I know the answer!
DNS root server
3
Lammle.com is:
198.1.78.115
If your first DNS server doesn’t know the answer to the query, then the DNS server for-wards a
TCP request to its root DNS server. Once the query is resolved, the answer is trans-mitted back to
the originating host, which means the host can now request the information from the correct web
server.
DNS is used to resolve a fully qualified domain name (FQDN)—for example,
www.lammle.com or todd.lammle.com. An FQDN is a hierarchy that can logically locate a
system based on its domain identifier.
If you want to resolve the name todd, you must either type in the FQDN of todd.lammle
.com or have a device such as a PC or router add the suffix for you. For example, on a Cisco
router, you can use the command ip domain-name lammle.com to append each request with the
lammle.com domain. If you don’t do that, you’ll have to type in the FQDN to get DNS to resolve
the name.
An important thing to remember about DNS is that if you can ping a device with
an IP address but cannot use its FQDN, then you might have some type of DNS
configuration failure.
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Dynamic Host Configuration Protocol (DHCP)/Bootstrap
Protocol (BootP)
Dynamic Host Configuration Protocol (DHCP) assigns IP addresses to hosts. It allows for easier
administration and works well in small to very large network environments. Many types of
hardware can be used as a DHCP server, including a Cisco router.
DHCP differs from BootP in that BootP assigns an IP address to a host but the host’s hardware
address must first be entered manually in a BootP table on the BootP server. You can think of
DHCP as a dynamic BootP. But remember that BootP is also used to send an operating system to a
host and the host can boot from it. DHCP can’t do that.
But there’s still a lot of information a DHCP server can provide to a host when the host is
requesting an IP address from the DHCP server. Here’s a list of the most common types of
information a DHCP server can provide:
â– â–
IP address
â– â–
Subnet mask
â– â–
Domain name
â– â–
Default gateway (routers)
â– â–
DNS server address
â– â–
WINS server address
A client that sends out a DHCP Discover message in order to receive an IP address sends out a
broadcast at both layer 2 and layer 3:
â– â–
The layer 2 broadcast is all fs in hex, which looks like this: ff:ff:ff:ff:ff:ff.
â– â–
The layer 3 broadcast is 255.255.255.255, which means all networks and all hosts.
DHCP is connectionless, which means it uses User Datagram Protocol (UDP) at the
Transport layer, also known as the Host-to-Host layer.
Seeing is believing, so here’s an example of output from my analyzer showing the layer 2 and
layer 3 broadcasts:
Ethernet II, Src: 0.0.0.0 (00:0b:db:99:d3:5e),Dst: Broadcast(ff:ff:ff:ff:ff:ff) Internet Protocol, Src:
0.0.0.0 (0.0.0.0),Dst: 255.255.255.255(255.255.255.255)
The Data Link and Network layers are both sending out “all hands” broadcasts saying,
“Help—I don’t know my IP address!”
Figure 1.14 shows the process of a client-server relationship using a DHCP connection. This is
the four-step process a client takes to receive an IP address from a DHCP server:
1. The DHCP client broadcasts a DHCP Discover message looking for a DHCP server (UDP
port 67).
2. The DHCP server that received the DHCP Discover message sends a layer 2 unicast
DHCP Offer (UDP port 68) message back to the host.
3. The client then broadcasts to the server a DHCP Request message asking for the
offered IP address and possibly other information.
4. The server finalizes the exchange with a unicast DHCP Acknowledgment message.
44. Identify Common Applications and Their Impact on the Network 17
F i g u r e 1.14 DHCP client four-step process
Help! I don’t have an address!
Client broadcast
DHCPDiscover
Server unicast
DHCPOffer
How about this address?
Can’t I just use the
address I had before?
Client broadcast
DHCPRequest
Server unicast
DHCPACK
Fine! Here it is.
Awesome! I’m somebody now!
DHCP Conflicts
A DHCP address conflict occurs when two hosts use the same IP address. This sounds bad, and it
is!
During IP address assignment, a DHCP server checks for conflicts using the Ping program to
test the availability of the address before it’s assigned from the pool. If no host replies, then the
DHCP server assumes that the IP address is not already allocated. This helps the server know that
it’s providing a good address, but what about the host? To provide extra protection against that
terrible IP conflict issue, the host can broadcast for its own address!
A host uses something called a gratuitous ARP to help avoid a possible duplicate address. A
gratuitous ARP is an ARP response made to all devices on the network when there was never an
original ARP request. Using this gratuitous ARP, the DHCP client sends an ARP broadcast out on
the local LAN or VLAN using its newly assigned address to solve conflicts before they occur.
So, if an IP address conflict is detected, the address is removed from the DHCP pool (scope),
and it’s really important to remember that the address will not be assigned to a host until the
administrator resolves the conflict by hand!
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Exam Essentials
Identify Process/Application layer protocols. Telnet is a terminal emulation program that
allows you to log into a remote host and run programs. File Transfer Protocol (FTP) is a
connection-oriented service that allows you to transfer files. Trivial FTP (TFTP) is a connec-
tionless file transfer program. Simple Mail Transfer Protocol (SMTP) is a sendmail program.
Describe the functions of DNS and DHCP in the network. Dynamic Host Configuration
Protocol (DHCP) provides network configuration information (including IP addresses) to hosts,
eliminating the need to perform the configurations manually. Domain Name Service (DNS)
resolves hostnames—both Internet names such as www.lammle.com and device names such as
Workstation 2—to IP addresses, eliminating the need to know the IP address of a device for
connection purposes.
Describe the Purpose and Basic
Operation of the Protocols in the
OSI and TCP/IP Models
When networks first came into being, computers could typically communicate only with
computers from the same manufacturer. For example, companies ran either a com-plete DECnet
solution or an IBM solution, never both together. In the late 1970s, the
Open Systems Interconnection (OSI) reference model was created by the International
Organization for Standardization (ISO) to break through this barrier.
The OSI model was meant to help vendors create interoperable network devices and software in
the form of protocols so that different vendor networks could work in peaceable accord with each
other.
The Layered Approach
A reference model is a conceptual blueprint of how communications should take place. It addresses
all the processes required for effective communication and divides them into logical groupings
called layers. When a communication system is designed in this manner, it’s known as a layered
architecture because it’s hierarchical.
Models happen to be really important to software developers too. They often use a refer-ence
model to understand computer communication processes so they can determine which functions
should be accomplished on a given layer. This means that if someone is creat-
ing a protocol for a certain layer, they need to be concerned only with their target layer’s function.
Software that maps to another layers’ protocols and is specifically designed to be deployed there
will handle additional functions. The technical term for this idea is binding. The communication
processes that are related to each other are bound, or grouped together, at a particular layer.
46. Describe the Purpose and Basic Operation of the Protocols.............................................19
Advantages of Reference Models
The OSI model is hierarchical, and there are many advantages that can be applied to any layered
model, but as I said, the OSI model’s primary purpose is to allow different vendors’ networks to
interoperate.
Here’s a list of some of the more important benefits for using the OSI layered model:
â– â–
It divides the network communication process into smaller and simpler components,
facilitating component development, design, and troubleshooting.
â– â–
It allows multiple-vendor development through the standardization of network
components.
â– â–
It encourages industry standardization by clearly defining what functions occur at each layer of
the model.
â– â–
It allows various types of network hardware and software to communicate.
â– â–
It prevents changes in one layer from affecting other layers to expedite development.
â– â–
It eases the learning process by allowing you to understand the functions, benefits, and
considerations of one layer at a time instead of having to overcome one large and complex
subject.
The OSI Reference Model
One of best gifts the OSI specifications gives us is paving the way for the data transfer between
disparate hosts running different operating systems, like Unix hosts, Windows machines,
Macs, smartphones, and so on.
The OSI is a logical model, not a physical one. It’s essentially a set of guidelines that developers
can use to create and implement applications to run on a network. It also provides a framework for
creating and implementing networking standards, devices, and internetworking schemes.
The OSI has seven different layers, divided into two groups. The top three layers (known as the
upper layers) define how the applications within the end stations will communicate with each other
as well as with users. The bottom four layers define how data is transmitted end to end.
Figure 1.15 shows the three upper layers and their functions.
F i g u r e 1.15 The upper layers
Application • Provides a user interface
Presentation
• Presents data
• Handles processing such as encryption
Session • Keeps different applications’ data separate
47. 20 Chapter 1 â–
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When looking at Figure 1.15, understand that users interact with the computer at the
Application layer and also that the upper layers are responsible for applications communi-cating
between hosts. None of the upper layers knows anything about networking or net-work addresses
because that’s the responsibility of the four bottom layers.
Figure 1.16 shows the four lower layers and their functions. You can see that it’s these four
bottom layers that define how data is transferred through physical media like wire, cable, fiber
optics, switches, and routers. These bottom layers also determine how to rebuild a data stream
from a transmitting host to a destination host’s application.
F i g u r e 1.16 The lower layers
Transport
• Provides reliable or unreliable delivery
• Performs error correction before retransmit
Network • Provides logical addressing, which routers use for path determination
• Combines packets into bytes and bytes into frames
Data Link • Provides access to media using MAC address
• Performs error detection not correction
• Moves bits between devices
Physical
• Specifies voltage, wire speed, and pin-out of cables
The following network devices and protocols operate at all seven layers of the OSI model:
â– â–
Network management stations (NMSs)
â– â–
Web and application servers
â– â–
Gateways (not default gateways)
â– â–
Servers
â– â–
Network hosts
Basically, the ISO is pretty much the Emily Post of the network protocol world. Just as Ms. Post
wrote the book setting the standards—or protocols—for human social interaction, the ISO
developed the OSI reference model as the precedent and guide for an open network protocol set.
Defining the etiquette of communication models, it remains the most popular means of comparison
for protocol suites today.
As you’ve just seen, the OSI reference model has the following seven layers:
â– â–
Application layer (layer 7)
â– â–
Presentation layer (layer 6)
â– â–
Session layer (layer 5)
â– â–
Transport layer (layer 4)
â– â–
Network layer (layer 3)
â– â–
Data Link layer (layer 2)
â– â–
Physical layer (layer 1)
48. Describe the Purpose and Basic Operation of the Protocols.............................................21
Some people like to use a mnemonic to remember the seven layers, such as All People Seem
To Need Data Processing. Figure 1.17 shows a summary of the functions defined at each layer
of the OSI model.
F i g u r e 1.17 OSI layer functions
Application • File, print, message, database, and application services
Presentation • Data encryption, compression, and translation services
Session • Dialog control
Transport • End-to-end connection
Network • Routing
Data Link • Framing
Physical • Physical topology
I’ve separated the seven-layer model into three different functions: the upper layers, the
middle layers, and the bottom layers. The upper layers communicate with the user interface and
application, the middle layers do reliable communication and routing to a remote net-work, and
the bottom layers communicate to the local network.
With this in hand, you’re now ready to explore each layer’s function in detail!
The Application Layer
The Application layer of the OSI model marks the spot where users actually communi-cate to the
computer and comes into play only when it’s clear that access to the network will be needed soon.
Take the case of Internet Explorer (IE). You could actually uninstall every trace of networking
components like TCP/IP, the NIC card, and so on, and still use IE to view a local HTML
document. But things would get ugly if you tried to do things like view a remote HTML document
that must be retrieved because IE and other browsers act on these types of requests by attempting
to access the Application layer. So basically, the Application layer is working as the interface
between the actual application program and the next layer down by providing ways for the
application to send informa-tion down through the protocol stack. This isn’t actually part of the
layered structure because browsers don’t live in the Application layer, but they interface with it as
well as the relevant protocols when asked to access remote resources.
The Presentation Layer
The Presentation layer gets its name from its purpose: It presents data to the Application layer
and is responsible for data translation and code formatting. Think of it as the OSI model’s
translator, providing coding and conversion services. One very effective way of
49. 22 Chapter 1 â–
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ensuring a successful data transfer is to convert the data into a standard format before transmission.
Computers are configured to receive this generically formatted data and then reformat it back into
its native state to read it. An example of this type of translation ser-vice occurs when translating old
IBM Extended Binary Coded Decimal Interchange Code (EBCDIC) data to PC ASCII, the
American Standard Code for Information Interchange (often pronounced “askee”). So just
remember that by providing translation services, the Presentation layer ensures that data transferred
from the Application layer of one system can be read by the Application layer of another one.
The Session Layer
The Session layer is responsible for setting up, managing, and dismantling sessions between
Presentation layer entities and keeping user data separate. Dialog control between devices also
occurs at this layer.
The Transport Layer
The Transport layer segments and reassembles data into a single data stream. Services located at
this layer take all the various data received from upper-layer applications and then combine it
into the same, concise data stream. These protocols provide end-to-end data transport services
and can establish a logical connection between the sending host and destination host on an
internetwork.
A pair of well-known protocols called TCP and UDP are integral to this layer, and under-stand
that although both work at the Transport layer, TCP is known as a reliable service but UDP is not.
This distinction gives application developers more options because they have a choice between the
two protocols when they are designing products for this layer.
The Transport layer is responsible for providing mechanisms for multiplexing upper-layer
applications, establishing sessions, and tearing down virtual circuits. It can also hide the details of
network-dependent information from the higher layers as well as provide transpar-ent data transfer.
The term reliable networking can be used at the Transport layer. Reliable
networking requires that acknowledgments, sequencing, and flow control will all
be used.
The Transport layer can be either connectionless or connection-oriented, but because Cisco
really wants you to understand the connection-oriented function of the Transport layer, I’m
going to go into that in more detail here.
Connection-Oriented Communication
For reliable transport to occur, a device that wants to transmit must first establish a
connection-oriented communication session with a remote device (its peer system),
known as a call setup or a three-way handshake. Once this process is complete, the data transfer
occurs, and when it’s finished, a call termination takes place to tear down the virtual circuit.
50. Describe the Purpose and Basic Operation of the Protocols.............................................23
Figure 1.18 depicts a typical reliable session taking place between sending and receiving
systems. In it, you can see that both hosts’ application programs begin by notifying their indi-vidual
operating systems that a connection is about to be initiated. The two operating systems
communicate by sending messages over the network confirming that the transfer is approved and
that both sides are ready for it to take place. After all of this required synchronization takes place, a
connection is fully established and the data transfer begins. And by the way, it’s really helpful to
understand that this virtual circuit setup is often referred to as overhead!
F i g u r e 1.18 Establishing a connection-oriented session
Sender SYN Receiver
SYN/ACK
ACK
Connection established
Data transfer
(Send bytes of segments)
While the information is being transferred between hosts, the two machines periodically check
in with each other, communicating through their protocol software to ensure that all is going well
and that the data is being received properly.
Here’s a summary of the steps in the connection-oriented session—that three-way
handshake—pictured in Figure 1.18:
â– â–
The first “connection agreement” segment is a request for synchronization (SYN).
â– â–
The next segments acknowledge (ACK) the request and establish connection parameters—
the rules—between hosts. These segments request that the receiver’s sequencing is
synchronized here as well so that a bidirectional connection can
be formed.
â– â–
The final segment is also an acknowledgment, which notifies the destination host that the
connection agreement has been accepted and that the actual connection has been established.
Data transfer can now begin.
Flow Control
Since floods and losing data can both be tragic, we have a fail-safe solution in place known as flow
control. Its job is to ensure data integrity at the Transport layer by allowing applications to request
reliable data transport between systems. Flow control prevents a sending host on one side of the
connection from overflowing the buffers in the receiving host. Reliable data
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transport employs a connection-oriented communications session between systems, and the
protocols involved ensure that the following will be achieved:
â– â–
The segments delivered are acknowledged back to the sender upon their reception.
â– â–
Any segments not acknowledged are retransmitted.
â– â–
Segments are sequenced back into their proper order upon arrival at their destination.
â– â–
A manageable data flow is maintained in order to avoid congestion, overloading, or worse,
data loss.
Because of the transport function, network flood control systems really work well. Instead of
dumping and losing data, the Transport layer can issue a “not ready” indicator to the sender, or
potential source of the flood. This mechanism works kind of like a stop-light, signaling the
sending device to stop transmitting segment traffic to its overwhelmed peer. After the peer
receiver processes the segments already in its memory reservoir—its buffer—it sends out a
“ready” transport indicator. When the machine waiting to transmit the rest of its datagrams
receives this “go” indicator, it resumes its transmission. The pro-cess is pictured in Figure 1.19.
In a reliable, connection-oriented data transfer, datagrams are delivered to the receiving host
hopefully in the same sequence they’re transmitted. A failure will occur if any data segments are
lost, duplicated, or damaged along the way—a problem solved by having the receiving host
acknowledge that it has received each and every data segment.
A service is considered connection-oriented if it has the following characteristics:
â– â–
A virtual circuit, or “three-way handshake” is set up.
â– â–
It uses sequencing.
â– â–
It uses acknowledgments.
â– â–
It uses flow control.
F i g u r e 1.19 Transmitting segments with flow control
Sender Receiver
Buffer full
Not ready –
STOP!
Segments
processed
GO!
52. Describe the Purpose and Basic Operation of the Protocols.............................................25
Windowing
Ideally, data throughput happens quickly and efficiently. And as you can imagine, it would be
painfully slow if the transmitting machine had to actually wait for an acknowledgment after
sending each and every segment! The quantity of data segments, measured in bytes, that the
transmitting machine is allowed to send without receiving an acknowledgment is called a window.
The size of the window controls how much information is transferred from one end to the other
before an acknowledgment is required. While some protocols quantify information depending on
the number of packets, TCP/IP measures it by counting the number of bytes.
As you can see in Figure 1.20, there are two window sizes—one set to 1 and one set to 3. If you’ve
configured a window size of 1, the sending machine will wait for an acknowl-edgment for each
data segment it transmits before transmitting another one but will allow three to be transmitted
before receiving an acknowledgment if the window size is set to 3.
In this simplified example, both the sending and receiving machines are workstations.
Remember that in reality, the transmission isn’t based on simple numbers but in the amount of
bytes that can be sent!
F i g u r e 1. 20 Windowing
Sender Receiver
Window size of 1
Send 1 Receive 1
ACK 1
Send 1 Receive 2
ACK 2
Send 1
Send 2
Send 3
Send 4
Acknowledgments
Window size of 3
ACK 4
Reliable data delivery ensures the integrity of a stream of data sent from one machine to the
other through a fully functional data link. It guarantees that the data won’t be duplicated or lost.
This is achieved through something called positive acknowledgment
with retransmission—a technique that requires a receiving machine to communicate with the
transmitting source by sending an acknowledgment message to the sender when it receives data.
The sender documents each segment measured in bytes and then sends and