Network Interview Questions documents common networking concepts and protocols. It defines networking as interconnecting computers, describes bandwidth as the maximum data transfer rate of a connection, and VLAN as a logical grouping of ports on a switch. It also summarizes protocols like CIDR for IP address allocation, VLSM for subnetting, unicast for one-to-one transmission, multicast for one-to-many, and broadcast for one-to-all transmission. Key networking protocols like CDP, SNMP, OSPF, RIP, BGP, and PPPoE are also outlined.
Slides supporting the "Computer Networking: Principles, Protocols and Practice" ebook. The slides can be freely reused to teach an undergraduate computer networking class using the open-source ebook.
This document summarizes key topics related to IPv6 and routing in IP networks. It discusses IPv6 addressing architecture, including unicast addresses, link-local addresses, and multicast addresses. It also covers IPv6 packet format, extension headers, fragmentation, and ICMPv6. The document then discusses routing within IP networks, including IPv6 subnets, routing organization with autonomous systems, and interdomain routing protocols.
Slides supporting the "Computer Networking: Principles, Protocols and Practice" ebook. The slides can be freely reused to teach an undergraduate computer networking class using the open-source ebook.
Part 5 : Sharing resources, security principles and protocolsOlivier Bonaventure
Slides supporting the "Computer Networking: Principles, Protocols and Practice" ebook. The slides can be freely reused to teach an undergraduate computer networking class using the open-source ebook.
The document discusses routing protocols in IP networks and interdomain routing. It provides an overview of IPv6 neighbor discovery, routing protocols RIP and OSPF, and interdomain routing with BGP. Key concepts covered include how routers discover each other on the local link, distance vector and link-state routing, using areas in OSPF, and the path vector exchange in BGP to choose optimal routes between autonomous systems.
Presentation given at MPLS+SDN+NFVWORLD 2019 in Paris that shows how network architects can leverage the support for IPv6 Segment that is included in the Linux kernel to develop new end-to-end services that use IPv6 Segment Routing on clients, routers and servers.
Network Interview Questions documents common networking concepts and protocols. It defines networking as interconnecting computers, describes bandwidth as the maximum data transfer rate of a connection, and VLAN as a logical grouping of ports on a switch. It also summarizes protocols like CIDR for IP address allocation, VLSM for subnetting, unicast for one-to-one transmission, multicast for one-to-many, and broadcast for one-to-all transmission. Key networking protocols like CDP, SNMP, OSPF, RIP, BGP, and PPPoE are also outlined.
Slides supporting the "Computer Networking: Principles, Protocols and Practice" ebook. The slides can be freely reused to teach an undergraduate computer networking class using the open-source ebook.
This document summarizes key topics related to IPv6 and routing in IP networks. It discusses IPv6 addressing architecture, including unicast addresses, link-local addresses, and multicast addresses. It also covers IPv6 packet format, extension headers, fragmentation, and ICMPv6. The document then discusses routing within IP networks, including IPv6 subnets, routing organization with autonomous systems, and interdomain routing protocols.
Slides supporting the "Computer Networking: Principles, Protocols and Practice" ebook. The slides can be freely reused to teach an undergraduate computer networking class using the open-source ebook.
Part 5 : Sharing resources, security principles and protocolsOlivier Bonaventure
Slides supporting the "Computer Networking: Principles, Protocols and Practice" ebook. The slides can be freely reused to teach an undergraduate computer networking class using the open-source ebook.
The document discusses routing protocols in IP networks and interdomain routing. It provides an overview of IPv6 neighbor discovery, routing protocols RIP and OSPF, and interdomain routing with BGP. Key concepts covered include how routers discover each other on the local link, distance vector and link-state routing, using areas in OSPF, and the path vector exchange in BGP to choose optimal routes between autonomous systems.
Presentation given at MPLS+SDN+NFVWORLD 2019 in Paris that shows how network architects can leverage the support for IPv6 Segment that is included in the Linux kernel to develop new end-to-end services that use IPv6 Segment Routing on clients, routers and servers.
TCPLS closely integrates TCP and TLS by using new TLS record types to carry TCP control plane information. This allows TCP options and control data to be encrypted and authenticated within TLS records. TCPLS provides benefits like securing Multipath TCP connections, enabling stronger TCP Fast Open, providing more space for TCP options, allowing true TCP keepalives, securely releasing TCP sessions, supporting Happy Eyeballs, and enabling connection migration. The integrated TCPLS protocol could improve privacy, security and functionality compared to treating TCP and TLS as separate and independent protocols.
Slides supporting the "Computer Networking: Principles, Protocols and Practice" ebook. The slides can be freely reused to teach an undergraduate computer networking class using the open-source ebook.
The document discusses Ethernet, spanning tree protocol, WiFi, and IP version 4. It provides details on Ethernet frame formats, Ethernet switches and how spanning tree protocol elects a root switch and handles failures. It also describes WiFi standards, channel frequencies, and 802.11 frame formats. Finally, it summarizes the fields in an IP version 4 packet header.
Slides supporting the "Computer Networking: Principles, Protocols and Practice" ebook. The slides can be freely reused to teach an undergraduate computer networking class using the open-source ebook.
Slides supporting the "Computer Networking: Principles, Protocols and Practice" ebook. The slides can be freely reused to teach an undergraduate computer networking class using the open-source ebook.
Routing protocols RIP, OSPF, and BGP are discussed. RIP uses distance vector routing and shares periodic updates with direct neighbors. OSPF is an intra-domain link state protocol where routers flood their link state information. BGP is an inter-domain path vector protocol that shares the full path to a destination rather than just hop counts.
The document discusses various topics related to sharing resources and internet applications. It begins by covering medium access control protocols like ALOHA, CSMA, and CSMA/CD. It then discusses congestion control, including max-min fairness, router queuing strategies, and window-based congestion control. Finally, it summarizes several internet applications - DNS, email protocols like SMTP, and the basic web client-server architecture.
This document discusses several topics related to Internet protocols including congestion control using TCP, Explicit Congestion Notification, Stream Control Transmission Protocol (SCTP), and IPv6. It provides details on TCP congestion control using Additive Increase Multiplicative Decrease (AIMD), SCTP segments and connection establishment, IPv6 addressing architecture, and ICMPv6 functions like ping6 and traceroute6.
The document discusses making networking stacks more extensible through the use of eBPF programs. It describes how eBPF can be used to program IPv6 segment routing, make TCP more customizable through hooks in the stack, and allow routing protocols to be extended through plugins. Examples are given of using eBPF to add monitoring to TCP and implement flexible filtering in BGP. The performance impact of eBPF programs is shown to be minimal compared to native code implementations.
Future Internet protocols are evolving to support more innovation in the transport and network layers. Multipath TCP allows a TCP connection to use multiple paths to improve performance, with subflows that appear like regular TCP connections. QUIC is a new transport protocol developed by Google that aims to reduce web latency by supporting 0-RTT handshake and encrypting more headers. IPv6 Segment Routing simplifies MPLS networks by using node labels advertised in routing protocols to steer traffic on arbitrary paths through the network.
Keynote given at DRCN2018, shows that innovation is back in the transport and network layer with a description of Multipath TCP, QUIC and IPv6 Segment Routing.
The document discusses limitations of using local preference alone for interdomain routing. It explains that local preference allows each domain to define preferred paths but may not always converge to a stable solution. The order domains announce updates can affect the chosen paths, and some configurations could lead to perpetual route withdrawals. More attributes are needed to consistently optimize economics across domains.
The Transmission Control Protocol (TCP) is used by the vast majority of applications to transport their data reliably across the Internet and in the cloud. TCP was designed in the 1970s and has slowly evolved since then. Today's networks are multipath: mobile devices have multiple wireless interfaces, datacenters have many redundant paths between servers, and multihoming has become the norm for big server farms. Meanwhile, TCP is essentially a single-path protocol: when a TCP connection is established, the connection is bound to the IP addresses of the two communicating hosts and these cannot change. Multipath TCP (MPTCP) is a major modification to TCP that allows multiple paths to be used simultaneously by a single transport connection. Multipath TCP circumvents the issues mentioned above and several others that affect TCP. The IETF is currently finalising the Multipath TCP RFC and an implementation in the Linux kernel is available today.
This tutorial will present in details the design of Multipath TCP and the role that it could play in cloud environments. We will start with a presentation of the current Internet landscape and explain how various types of middleboxes have influenced the design of Multipath TCP. Second we will describe in details the connection establishment and release procedures as well as the data transfer mechanisms that are specific to Multipath TCP. We will then discuss several use cases for the deployment of Multipath TCP including improving the performance of datacenters and
mobile WiFi offloading on smartphones. All these use cases are key when both accessing cloud-based services or when providing them. We will end the tutorial with some open research issues.
This tutorial was given at the IEEE Cloud'Net 2012 conference in novembrer 2012.
The pptx version containing animations that are not shown here is available from http://www.multipath-tcp.org
Networking Fundamentals: Transport Protocols (TCP and UDP)Andriy Berestovskyy
Transport Layer of TCP/IP. Transmission Control Protocol (TCP) basics and network sockets explained. How TCP connection get established, error recovered and terminated.
User Datagram Protocol and its comparison to TCP. Quality of Service (QoS).
Beyond TCP: The evolution of Internet transport protocolsOlivier Bonaventure
The transport layer is one of the key layers of the Internet protocol stack. It enrichs the network layer service to make it suitable for applications. Almost 40 years after its initial design, TCP remains the most widely used transport protocol. In the early 2000s, SCTP was proposed as an alternative to TCP. Despite a clean and extensible design and many useful features, it did not reach wide deployment. This failure is mainly caused by middleboxes. We'll describe their operation and explain why Multipath TCP, which is a backward compatible evolution to TCP, has better chances of being deployed. We'll explain the main principles behind Multipath TCP and the lessons that can be drawn from its design. We'll then analyse why Internet giants like Google and Microsoft now consider application-layer solutions like QUIC to replace standard protocols like TCP.
Ports and sockets allow processes on the same device to communicate over a network. Every TCP connection is uniquely identified by its two endpoints - the source port and destination port. Ports map incoming data to specific processes using port numbers between 0-65535. A socket is the endpoint of a connection and is defined by an IP address and port number combination. Sockets provide an interface for programming networks at the transport layer and allow devices to establish connections to communicate.
DHCP allows devices to obtain IP addresses and other network configuration dynamically. It uses a series of packet exchanges between DHCP clients and servers. The document discusses the DHCP packet types, client-server conversation process, DHCP snooping for security, and commands used to configure and monitor DHCP. It also covers Dynamic ARP inspection and IP Source Guard which work with DHCP snooping to provide additional network security.
Fourth lesson of the Computer Networking class. Covers reliable transport principles and the introduction for sharing resources (MAC and congestion control)
This document discusses various topics relating to the network layer, including:
1. The network layer transports data segments between hosts by encapsulating them into datagrams and routing them through routers and links.
2. Routers examine header fields to determine how to forward datagrams to their destination, either based on destination address or other header values.
3. The network layer provides forwarding to move packets between router interfaces and routing to determine the path between source and destination. Control planes implement routing algorithms while data planes perform packet forwarding.
Many applications are network I/O bound, including common database-based applications and service-based architectures. But operating systems and applications are often untuned to deliver high performance. This session uncovers hidden issues that lead to low network performance, and shows you how to overcome them to obtain the best network performance possible.
Regular expressions are strings that define patterns to match character sequences. They can be used in Cisco IOS show commands and AS-Path access-lists to match BGP prefixes based on AS-Path information. Regular expression characters have specific meanings, such as ^ and $ to match the start and end, [] for ranges, and * + ? for quantity. An example expression matches routes originated from directly connected ASes or their customers by representing AS numbers as "X" and using quantity symbols to account for multi-digit ASNs.
This document provides instructions for configuring packet capture on a Cisco ASA firewall. It describes using the packet capture wizard in ASDM or CLI commands to define a capture named "capin" on the inside interface and "capout" on the outside interface. The capture filters use access lists to match traffic between the inside and outside networks. The show capture command can then be used to view the captured packets.
TCPLS closely integrates TCP and TLS by using new TLS record types to carry TCP control plane information. This allows TCP options and control data to be encrypted and authenticated within TLS records. TCPLS provides benefits like securing Multipath TCP connections, enabling stronger TCP Fast Open, providing more space for TCP options, allowing true TCP keepalives, securely releasing TCP sessions, supporting Happy Eyeballs, and enabling connection migration. The integrated TCPLS protocol could improve privacy, security and functionality compared to treating TCP and TLS as separate and independent protocols.
Slides supporting the "Computer Networking: Principles, Protocols and Practice" ebook. The slides can be freely reused to teach an undergraduate computer networking class using the open-source ebook.
The document discusses Ethernet, spanning tree protocol, WiFi, and IP version 4. It provides details on Ethernet frame formats, Ethernet switches and how spanning tree protocol elects a root switch and handles failures. It also describes WiFi standards, channel frequencies, and 802.11 frame formats. Finally, it summarizes the fields in an IP version 4 packet header.
Slides supporting the "Computer Networking: Principles, Protocols and Practice" ebook. The slides can be freely reused to teach an undergraduate computer networking class using the open-source ebook.
Slides supporting the "Computer Networking: Principles, Protocols and Practice" ebook. The slides can be freely reused to teach an undergraduate computer networking class using the open-source ebook.
Routing protocols RIP, OSPF, and BGP are discussed. RIP uses distance vector routing and shares periodic updates with direct neighbors. OSPF is an intra-domain link state protocol where routers flood their link state information. BGP is an inter-domain path vector protocol that shares the full path to a destination rather than just hop counts.
The document discusses various topics related to sharing resources and internet applications. It begins by covering medium access control protocols like ALOHA, CSMA, and CSMA/CD. It then discusses congestion control, including max-min fairness, router queuing strategies, and window-based congestion control. Finally, it summarizes several internet applications - DNS, email protocols like SMTP, and the basic web client-server architecture.
This document discusses several topics related to Internet protocols including congestion control using TCP, Explicit Congestion Notification, Stream Control Transmission Protocol (SCTP), and IPv6. It provides details on TCP congestion control using Additive Increase Multiplicative Decrease (AIMD), SCTP segments and connection establishment, IPv6 addressing architecture, and ICMPv6 functions like ping6 and traceroute6.
The document discusses making networking stacks more extensible through the use of eBPF programs. It describes how eBPF can be used to program IPv6 segment routing, make TCP more customizable through hooks in the stack, and allow routing protocols to be extended through plugins. Examples are given of using eBPF to add monitoring to TCP and implement flexible filtering in BGP. The performance impact of eBPF programs is shown to be minimal compared to native code implementations.
Future Internet protocols are evolving to support more innovation in the transport and network layers. Multipath TCP allows a TCP connection to use multiple paths to improve performance, with subflows that appear like regular TCP connections. QUIC is a new transport protocol developed by Google that aims to reduce web latency by supporting 0-RTT handshake and encrypting more headers. IPv6 Segment Routing simplifies MPLS networks by using node labels advertised in routing protocols to steer traffic on arbitrary paths through the network.
Keynote given at DRCN2018, shows that innovation is back in the transport and network layer with a description of Multipath TCP, QUIC and IPv6 Segment Routing.
The document discusses limitations of using local preference alone for interdomain routing. It explains that local preference allows each domain to define preferred paths but may not always converge to a stable solution. The order domains announce updates can affect the chosen paths, and some configurations could lead to perpetual route withdrawals. More attributes are needed to consistently optimize economics across domains.
The Transmission Control Protocol (TCP) is used by the vast majority of applications to transport their data reliably across the Internet and in the cloud. TCP was designed in the 1970s and has slowly evolved since then. Today's networks are multipath: mobile devices have multiple wireless interfaces, datacenters have many redundant paths between servers, and multihoming has become the norm for big server farms. Meanwhile, TCP is essentially a single-path protocol: when a TCP connection is established, the connection is bound to the IP addresses of the two communicating hosts and these cannot change. Multipath TCP (MPTCP) is a major modification to TCP that allows multiple paths to be used simultaneously by a single transport connection. Multipath TCP circumvents the issues mentioned above and several others that affect TCP. The IETF is currently finalising the Multipath TCP RFC and an implementation in the Linux kernel is available today.
This tutorial will present in details the design of Multipath TCP and the role that it could play in cloud environments. We will start with a presentation of the current Internet landscape and explain how various types of middleboxes have influenced the design of Multipath TCP. Second we will describe in details the connection establishment and release procedures as well as the data transfer mechanisms that are specific to Multipath TCP. We will then discuss several use cases for the deployment of Multipath TCP including improving the performance of datacenters and
mobile WiFi offloading on smartphones. All these use cases are key when both accessing cloud-based services or when providing them. We will end the tutorial with some open research issues.
This tutorial was given at the IEEE Cloud'Net 2012 conference in novembrer 2012.
The pptx version containing animations that are not shown here is available from http://www.multipath-tcp.org
Networking Fundamentals: Transport Protocols (TCP and UDP)Andriy Berestovskyy
Transport Layer of TCP/IP. Transmission Control Protocol (TCP) basics and network sockets explained. How TCP connection get established, error recovered and terminated.
User Datagram Protocol and its comparison to TCP. Quality of Service (QoS).
Beyond TCP: The evolution of Internet transport protocolsOlivier Bonaventure
The transport layer is one of the key layers of the Internet protocol stack. It enrichs the network layer service to make it suitable for applications. Almost 40 years after its initial design, TCP remains the most widely used transport protocol. In the early 2000s, SCTP was proposed as an alternative to TCP. Despite a clean and extensible design and many useful features, it did not reach wide deployment. This failure is mainly caused by middleboxes. We'll describe their operation and explain why Multipath TCP, which is a backward compatible evolution to TCP, has better chances of being deployed. We'll explain the main principles behind Multipath TCP and the lessons that can be drawn from its design. We'll then analyse why Internet giants like Google and Microsoft now consider application-layer solutions like QUIC to replace standard protocols like TCP.
Ports and sockets allow processes on the same device to communicate over a network. Every TCP connection is uniquely identified by its two endpoints - the source port and destination port. Ports map incoming data to specific processes using port numbers between 0-65535. A socket is the endpoint of a connection and is defined by an IP address and port number combination. Sockets provide an interface for programming networks at the transport layer and allow devices to establish connections to communicate.
DHCP allows devices to obtain IP addresses and other network configuration dynamically. It uses a series of packet exchanges between DHCP clients and servers. The document discusses the DHCP packet types, client-server conversation process, DHCP snooping for security, and commands used to configure and monitor DHCP. It also covers Dynamic ARP inspection and IP Source Guard which work with DHCP snooping to provide additional network security.
Fourth lesson of the Computer Networking class. Covers reliable transport principles and the introduction for sharing resources (MAC and congestion control)
This document discusses various topics relating to the network layer, including:
1. The network layer transports data segments between hosts by encapsulating them into datagrams and routing them through routers and links.
2. Routers examine header fields to determine how to forward datagrams to their destination, either based on destination address or other header values.
3. The network layer provides forwarding to move packets between router interfaces and routing to determine the path between source and destination. Control planes implement routing algorithms while data planes perform packet forwarding.
Many applications are network I/O bound, including common database-based applications and service-based architectures. But operating systems and applications are often untuned to deliver high performance. This session uncovers hidden issues that lead to low network performance, and shows you how to overcome them to obtain the best network performance possible.
Regular expressions are strings that define patterns to match character sequences. They can be used in Cisco IOS show commands and AS-Path access-lists to match BGP prefixes based on AS-Path information. Regular expression characters have specific meanings, such as ^ and $ to match the start and end, [] for ranges, and * + ? for quantity. An example expression matches routes originated from directly connected ASes or their customers by representing AS numbers as "X" and using quantity symbols to account for multi-digit ASNs.
This document provides instructions for configuring packet capture on a Cisco ASA firewall. It describes using the packet capture wizard in ASDM or CLI commands to define a capture named "capin" on the inside interface and "capout" on the outside interface. The capture filters use access lists to match traffic between the inside and outside networks. The show capture command can then be used to view the captured packets.
This document provides an overview and study guide for the CCIP MPLS exam. It discusses key MPLS concepts like label distribution, label switching, and MPLS VPNs. The exam tests knowledge of MPLS fundamentals, frame and cell mode MPLS, MPLS VPN implementation, complex MPLS VPNs, and internet access from an MPLS VPN. It provides details on topics covered in the exam and guidance on how to prepare.
This document provides an overview of Cisco Quality of Service (QoS) methods and configuration. It discusses legacy CLI, Modular QoS CLI (MQC), and AutoQoS features for implementing QoS policies. It also covers traffic classification, marking, queuing mechanisms like weighted fair queuing (WFQ) and low-latency queuing (LLQ), and configuration of QoS on switches.
This document discusses troubleshooting basic BGP connectivity between two sites. It describes the three tables that BGP connectivity is built upon: the neighbor table showing BGP session state, the BGP table learning prefixes, and the IP route table selecting best routes from the BGP table based on attributes like weight, local preference, AS-path length. The document also states that a candidate with BGP knowledge should be able to accurately describe connectivity between two sites using BGP.
Firewalls work by denying or permitting network traffic based on configured policies. A firewall protects internal networks from unauthorized external access and can also separate internal networks. Stateful firewalls are aware of network connections and maintain related information in a connection table, while stateless firewalls make decisions based only on individual packets.
The document provides an overview of multihoming and BGP routing. It discusses how multihoming works without BGP by default routing traffic out multiple connections, but requiring the ISPs to advertise routes to bring traffic back in. It then explains how BGP allows networks to advertise specific routes and policies to control traffic flow when multihomed. The document outlines basic BGP concepts like autonomous systems, route attributes, and how routes and policies are exchanged between networks using BGP.
5G transport networks require re-architecting to meet new bandwidth, delay, synchronization, infrastructure, and architecture requirements for 5G services like eMBB, uRLLC, and mMTC. Key technologies for 5G transport include IP routing, MPLS VPN, FlexE, and segment routing to provide the necessary slicing, bandwidth, and latency while supporting a flexible, cloud-based architecture.
This document contains 21 multiple choice questions and answers from the CCNA 1 Chapter 9 exam on network fundamentals. The questions cover topics like Ethernet protocols, data encapsulation, MAC addressing, collision detection using CSMA/CD, and Ethernet switching fundamentals.
1. Serial0 is up but the line protocol is down, indicating a potential issue with the cable or configuration settings not matching on both ends.
2. Static IP addresses are manually assigned while dynamic IP addresses are assigned by a DHCP server from its IP range, and have a lease duration after which the address may change.
3. Protocols establish rules and standards for moving data across a network, such as routing protocols like RIP, IGRP, and EIGRP that determine the best path between networks.
Device Replacement/Network Replication are some of the most important procedures in Industrial Automation. So far Ethernet/IP Industrial automation networks lacked simple unified strategy for performing these procedures. This paper presents an algorithm which uses LLDP and DHCP protocols to accomplish Device Replacement/Network Rollout where address assignment is accomplished purely via topology information. This approach has fewer restrictions that some other Device Replacement protocols in other Ethernet Fieldbuses and therefore saves cost due to reduced number of manual steps.
R1 is configured to use SNMP version 2 to communicate with a management station at IP address 192.168.1.3. However, the administrator is unable to get any information from R1. The problem is likely due to an issue with the ACL configuration that was applied to limit access to the SNMP community. The ACL permits traffic from 192.168.10.3 but it is unclear if this is the correct IP address for the management station.
PortLand is a scalable, fault-tolerant layer 2 data center network fabric protocol that addresses limitations in existing protocols. It uses positional pseudo MAC addresses to encode host locations, a centralized fabric manager for topology information, and distributed location discovery for switches to determine their position without configuration. PortLand provides loop-free forwarding, fast failure recovery through alternate paths, and supports VM migration across physical machines.
The document provides answers to questions about CCNA 4 Chapter 2. It discusses configuring PPP encapsulation and authentication between two routers to establish a serial connection. It also covers concepts like TDM, HDLC, LCP, CHAP authentication, and using show commands to troubleshoot PPP issues.
The document discusses the key responsibilities and functions of the network layer in computer networking. The network layer is responsible for getting packets from their source to their destination across multiple hops and routers. It must choose appropriate paths through the network topology and balance traffic loads across lines and routers. The network layer provides either a connectionless or connection-oriented service and uses different packet forwarding mechanisms depending on the chosen service.
Cisco discovery d homesb module 3 - v.4 in english.igede tirtanata
This document contains a quiz with 20 multiple choice questions about networking concepts such as encapsulation, MAC addresses, ARP protocol, routing tables, default gateways, and file sharing. It asks the learner to identify networking devices, standards, functions, and impacts of misconfigurations. The questions cover topics like Ethernet, TCP/IP, routing, and basic network security.
The document contains a 20 question multiple choice exam about networking technologies like HSRP, SNMP, VLANs, STP, QoS, VoIP, and security. The questions cover topics such as router redundancy protocols, switch configuration, trunking protocols, and network hardening techniques.
Each router using a link-state routing protocol builds a complete and synchronized view of the network topology. This is achieved by routers flooding the network with link-state advertisements (LSAs) that describe the state of their links. With a complete view of the network, routing loops are difficult to occur since each router can independently calculate the optimal path to each destination.
Www ccnav5 net_ccna_1_chapter_5_v5_0_exam_answers_2014Đồng Quốc Vương
This document provides the questions and answers for CCNA 1 Chapter 5 v5.0 exam. It includes 20 multiple choice questions about networking topics like ARP, MAC addressing, Ethernet switching, and Ethernet frame structure. The questions test knowledge of how switches forward frames based on MAC address tables, how ARP requests work to resolve IP to MAC mappings, and characteristics of Ethernet like preamble purpose and contention-based access methods.
This document provides an overview of routing protocols and network security concepts. It discusses distance vector protocols like RIP, path vector protocols like BGP, and link state protocols like OSPF. It covers routing attacks such as source routing, spoofing, and man-in-the-middle attacks. It also discusses secure routing requirements and authentication methods used in protocols.
This document provides the questions and answers for CCNA 1 Chapter 6 exam. It tests knowledge of router configuration commands, IPv4 and IPv6 addressing, routing tables, router interfaces, and memory. Some key points covered are that the copy running-config startup-config command saves the router configuration, the differentiated services field defines packet priority, and NAT is not needed in IPv6 because of the huge number of available addresses.
The document provides information about network configuration and security best practices:
1. HTTPS should be used to transfer credit card information on a company website to encrypt the transmission.
2. A branch office router connecting to headquarters should be configured with encapsulation PPP and IP address 192.168.5.21 to establish the serial connection.
3. The service password-encryption and enable secret commands ensure passwords are encrypted in the router configuration.
This document discusses computer network fundamentals, including network terminologies, port addressing, TCP/IP encapsulation and decapsulation, important header fields, IP fragmentation versus TCP segmentation, static and dynamic routing protocols, types of dynamic routing protocols such as distance vector and link state protocols, and examples of specific routing protocols including RIP, EIGRP, and OSPF. Key topics covered include how ports and IP addresses are used to uniquely identify network processes, the encapsulation and decapsulation process, fields included in packet headers, how packets are fragmented at different layers, and characteristics of different routing protocol types.
The document discusses routers and routing. It begins by defining a router as a specialized computer that sends packets over a network by selecting the best path and forwarding packets to their destination. It then covers router architecture, including input and output ports, switching fabrics, routing processors, and forwarding tables. The document also discusses different routing techniques like source routing, virtual circuits, and forwarding using IP addresses. It explains how routing tables are used to determine the next hop for packet forwarding.
Similar to Surviving The Stump The Chump Interview Questions (20)
OSPF Beyond Stump-the-Chump_Interview_Questions - Part 01 -Duane Bodle
This presentation is meant to help other network engineers to understand and put OSPF into the production networks correctly and with the least pain possible. Make no mistake, OSPF designed and deploy incorrectly can and is a bad experience.
SIP is a protocol that establishes, modifies, and terminates multimedia sessions like internet phone calls. It works between the session and application layers and can work with both IPv4 and IPv6. SIP provides functions for user location, availability, capabilities, session setup, and management. It is a flexible protocol that allows developers to build additional features.
Project Business Case and Capital Justification for Implementation of Applica...Duane Bodle
Business Case and Capital Justification Presentation For
Application Performance Monitoring and Retrospective Network Analysis Implementation. *** This Presentation Has Been Sanitized of IP Information ***
This document discusses the different LSA (Link State Advertisement) types in OSPF (Open Shortest Path First) networking. It explains that LSA types 1 and 2 are intra-area and do not leave the area, while type 3 are inter-area and describe routes outside the area. LSA types 5 and 7 describe redistributed routes from other protocols into an OSPF area, with type 5 generated by ASBR (Autonomous System Boundary Router) and type 7 by ASBR within a NSSA (Not-So-Stubby Area).
BGP is an exterior gateway protocol used for routing between autonomous systems (AS) and is the main protocol for routing between Internet service providers. It uses TCP port 179 and establishes peering sessions between routers in different AS to exchange routing information. BGP selects the best path to a destination based on attributes like AS path length, local preference, and MED. It is used in situations like multi-homed customer networks and large enterprise networks connected to multiple ISPs or AS.
The document provides an overview of BGP (Border Gateway Protocol) including its uses, basics, route selection criteria, advertising networks, summarization, aggregation, securing peers, multihoming, filtering, and other configuration topics. BGP is an exterior gateway protocol used for routing between autonomous systems and uses TCP port 179. Key attributes include NEXT_HOP, AS_PATH, and ORIGIN.
1. October 12, 2012 [STUMP THE CHUMP TECHNICAL SCREEN QUESTIONS]
2)Late Collision in computer networking is a type of collision found in CSMA/CD based protocols.
Specifically a late collision is one that happens further into the packet than is allowed for by the protocol
standard in question.
In 10 megabit shared medium ethernet, if a collision error occurs after the first 512 bits of data are
[1]
transmitted by the transmitting station, a late collision is said to have occurred. Importantly, late
collisions are not re-sent by the NIC unlike collisions occurring before the first 64 octets; it is left for the
upper layers of the protocol stack to determine that there was loss of data.
As a correctly set up CSMA/CD network link should not have late collisions, the usual possible causes
are full-duplex/half-duplex mismatch, exceeded Ethernet cable length limits, or defective hardware such
as incorrect cabling, non-compliant number of hubs in the network, or a bad NIC.
3) Hot Standby Router Protocol (HSRP) is a Cisco proprietary redundancy protocol for establishing a
fault-tolerant default gateway, and has been described in detail in RFC 2281.
The protocol establishes a framework between network routers in order to achieve default gateway
[1]
failover if the primary gateway becomes inaccessible, in close association with a rapid-converging
routing protocol like EIGRP or OSPF. By multicasting packets,
Page 1
2. October 12, 2012 [STUMP THE CHUMP TECHNICAL SCREEN QUESTIONS]
4) HSRP sends its hello messages to the multicast address 224.0.0.2(all routers) for version 1, or
[2]
224.0.0.102for version 2 , using
UDP port 1985, to other HSRP-enabled routers, defining priority between the routers. The primary router
with the highest configured priority will act as a virtual router with a pre-defined gateway IP address and
will respond to the ARP request from machines connected to the LAN with the MAC
address0000.0c07.acXXwhere XX is the group ID in hex. If the primary router should fail, the router with
the next-highest priority would take over the gateway IP address and answer ARP requests with the same
mac address, thus achieving transparent default gateway fail-over
5) Priority and Preempt, (Load Balancing)
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6) Ping the desired IP address, then do a show ARP on the Default gateway of the device, This gives you
the MAC Address, Then do a “ Show Mac-Address Address “MAC ADDRESS FROM SHOW ARP” To get the
interface associated with that MAC.
Or if this is a Cisco Device and you are looking for Cisco Device you could do a Show CDP Neighbor.
7) Think of it like a highway - the only difference being is the car traveling the highway cannot "choose"
which off-ramp to take, it has to be told.
Computer "A" on network "A" sends the messenger in his car down the freeway (ethernet). As he leaves
the building (the computer) he travels down a side street (ether cable) and finally comes into contact with
the main traffic. On a 24 port switch, see this as being a long "main" street with 24 exist or side-streets.
As the car travels past each street (device plugged directly into the switch) the driver calls out "I'm going
to such-and-such address!" and if the computer on that branch answers "Hey, that's me!" the car
continues on the path.
Now, when there's another switch involved where the destination computer resides, the car travels past
the street where the other switch is connected. The driver screams out the intended address, but this
time, the network "B" switch says "I'm not him, but he's down this way!"
Once the driver heads onto the other "main street" the same process begins again.
Sorry if the analogy sounds "childish" but it tends to get the correct idea across to packet forwarding, TCP
itself and how Ethernet functions.
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8) Frame Relay is a standardized wide area network technology that specifies the physical and logical
link layers of digital telecommunications channels using a packet switching methodology. Originally
designed for transport across Integrated Services Digital Network (ISDN) infrastructure, it may be used
today in the context of many other network interfaces.
9) A data link connection identifier (DLCI) is a Frame Relay 10 bit wide link-local virtual circuit identifier
used to assign frames to a specific PVC or SVC. Frame Relay networks use DLCIs to statistically
[1]
multiplex frames. DLCIs are preloaded into each switch and act as road signs to the traveling frames.
The standard allows the existence of 1024 DLCIs, however only numbers from 16 to 991 are available for
[2]
end users' equipment. The rest are reserved for various management purposes.
10) BECN: BECN (Backward Error Congestion Notification)
If device A is sending data to device B across a Frame Relay infrastructure and one of the intermediate
Frame Relay switches encounters congestion, congestion being full buffers, over subscribed port,
overloaded resources, etc, it will set the BECN bit on packets being returned to the sending device and
the FECN bit on the packets being sent to the receiving device. This has the effect of telling the sending
router to Back offand apply flow control like traffic Shaping and informs the receiving device that the
flow is congestedand that it should inform upper layer protocols, if possible, that it should close down
windowing etc to inform the sending application to slow down.
A FECN tells the receiving device that the path is congested so that the upper layer protocols should
expect some delay. The BECN tells the transmitting device that the Frame Relay network is congested
and that it should "back off" to allow better throughput.
FECN (Forward Error Congestion Notification)
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BGP:
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BGP:
1. What is BGP?
a. Border Gateway Protocol
2. What is a BGP Autonomous System?
a. A defined routing domain containing some number of subnets also known as “prefixes
3. What port/ports do BGP use?
a. TCP port 179
4. What command would you use to look at a brief summary of your BGP peers and their status?
a. Show IP BGP Neighbors
b. Show IP BGP Summary
5. If you see one of the Peers is in Active mode what does that mean? Is it good or Bad?
a. Active means the router is trying to establisha BGP session, nothing more.
b. It does NOT mean TCP connectivity to the neighbor is OK at the moment.
c. I would say that this is not good sign:
i. the BGP session is configured on your side and the BGP neighbor state machine for this
neighbor has been started.
ii. but the configuration may be missing on the other side for example or there is a problem of
TTL if it is an eBGP session
d. The state to look for is established in shipbgp neigh.
i. in shipbgp sumyou should see the number of rx prefixes(including 0 special case)
6. What are some of the well known BGP Attributes?
a. Well-known attributes must be recognized by all BGP implementations. Some of these attributes
are mandatory and must be included in every UPDATE message.
b. Origin
c. AS_Path
d. Next_Hop
e. Multi_Exit_Descriminator
f. Local_Preference (Discretionary)
g. Atomic_Aggregate (Discretionary)
7. What is AS Path prepending?
R6(config)# route-map PREPEND permit 10
R6(config-route-map)# set as-path prepend 67 67
R6(config-route-map)# router bgp 67
R6(config-router)# neighbor 172.31.68.8 route-map PREPEND out
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8. What are BGP Communities?
The BGP community attribute is a numerical value that can be assigned to a specific prefix
and advertised to other neighbors. When the neighbor receives the prefix it will examine the
community value and take proper action whether it is filtering or modifying other attributes.
By default the community attribute is removed from the update before being sent to the
neighbor. To allow community values to be sent to a specific neighbor the
command neighbor x.x.x.x send-community must be applied.
BGP has default 4 well known communitiesthat can be used to mark prefixes; listed as
follows:
Internet: advertise these routes to all neighbors.
Local-as: prevent sending routes outside the local As within the confederation.
No-Advertise: do not advertise this route to any peer, internal or external.
No-Export: do not advertise this route to external BGP peers.
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How to set community attribute values?
Network command: the optional route-map at the end of the network command can
be used to set the community of the advertised prefix.
Aggregate address: the Attribute-map option can be used to set the attributes of the
aggregate route including the community value.
Neighbor command: a route-map can be used to set the community of specific
prefixes received from or sent to the neighbor.
Redistribution: you can set the community attribute of the redistributed prefixes
using the route-map option of the redistribute command.
9. If you are peering between two different Autonomous systems and using loopback addresses,
are there any special neighbor commands that need to be applied for the BGP peers to come up?
a. >>>>Answer:
b. Neighbor “IP Address” ebgp-multihop2 {IF External AS Peer}
c. Neighbor “IP Address” update-source Loopback”#”
10. Are there any specific commands needed if you are peering using loopback addresses between
two devices in the same AS?
a. Must have connectivity Either IGPor a Static route
b. Neighbor “IP Address” update-source Loopback”#”
11. Will this work?
a. No
12. Why?
a. Because of BGP Split Horizon…eBGP route updates are not past into the iBGP
domain because the route source is not changed.
13. What needs to be AS 65666 for this to work?
1. Neighbor “IP Address” next-hop-self
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15. Are there any other ways to make this work?
1. Route Reflectors
2. Confederation
16. What is BGP split horizon?
1. BGP doesn't really have a split horizon rule. iBGP refuses to talk to anybody
except it's friends unless you specifically tell it to via route reflector or
confederation. EBGP doesn't care, it'll take any route from anyone unless
specifically configured to ignore them, and then just decides what is the best
path and drops that into the routing table. If the best path goes away, if it has
other routes, it'll insert the next best path into the routing table.
17. Explain BGP synchronization, why would we turn that off?
1. BGP requires that IF a prefix is learned from a 1st AS and will transit your AS
destined for a 3rd AS THEN the route will not be advertised until all routers within the
AS have learned about the route via an IGP.
EIGRP
1. What is the basic components that make up the metric of an EIGRP route
1. Bandwidth, Delay, Load, Reliability
2. What is feasible successor?
1. It is the second best route to a destination that meets the feasibility condition
as calculated by the DUAL / Diffusing Update Algorithm
3. Where can you find a list of feasible successors?
1. They are stored in the Topology Table
4. What is the feasible distance
1. FD = [Cost between the local router and the next-hop router] + (AD)
2. I think FD is rather calculated as below which even the IOS output confirms
3. FD=256* (( 10^7/Lowest BW along path in Kbps) + ( Cumulative Delay in
microsec/10) )
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OSPF:
1. Can you name 3 differentLSA types and what they are used for?
2.
3. What us the different between a stubby and a not so stubby area?
1. Stub areasexist to reduce the number of LSAs that are processed within an area. This is done by
sacrificing some information. Practically, this means we filter out various routes that are coming
into the area and replace it with a default route.
2. Remember that as a link state protocol, all routers within the area have to have the same
information, so most of the work is done on the ABR.
3. A stubby area ignores external routes (O E1, O E2), and permits both inter and intra area routes
(O IA and O). The path to the external routes is replaced by a default route injected by the ABR.
4. So an ABR operating in stubby mode filters out type 5 LSAs.
5. ASBRS AND EXTERNAL ROUTES ARE NOT ALLOWED IN STUBS
4. Hence the NSSA. An NSSAbehaves the same as a stubby area except that ASBRs are allowed, with some
trickery happening to get around the rules.
5. In an NSSA, external routes are allowed if they originate inside. The ABRs still filter out the type 5 LSAs at
the border. Any ASBR within an NSSA advertises external routes as type 7 routes instead of type 5. Thus,
they show up in the routing table as O N1 instead of O E1. The ABRconverts the type 7 LSA into a type 5
LSA before it advertises the LSA to the backbone.
6. Because of the restriction on the type 5 LSAs, and the need to understand type 7 LSAs, all routers in the
area need to be configured as an NSSA.
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7. The “no-summary” still exists, and is only needed on the ABR. So, in addition to the NSSA behaviour, you’re
still allowed to filter out those interarea type 3 LSAs at the border.
1. NSSAs are goofy in that you need to originate a default route explicitly in the nssa command.
8. Within OSPF why do you need area 0?
1. Area 0 is needed to prevent routing loops.
9. If you are redistributing another routing protocol in OSPF (for example: 172.16.1.0/24)
what could be the cause that you are only seeing the summarized route 172.16.0.0/16
5. What is the difference between external type 1 and external type 2 OSPF routes.
6. What would you do to speed up convergence in an OSPF network
7. If all configurations are standard and you have a gig and fastE link to a destination
network. Which link would the OSPF process prefer.
8. Why?
9. How can you influence the decision?
F5 BIGIP
1. Questions are based on V4.
2. What is a VIP?
3. What is persistence?
4. What command would you use to display the current status of a VIP?
5. What command would you use display the persistence settings on a particular VIP
configurations?
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