The document discusses the differences between routers, hubs, and switches. It states that hubs are used to connect network segments and copy packets to all ports. Switches operate at the data link layer and filter and forward packets between network segments. Routers are located at gateways where two or more networks connect, and use headers and tables to determine the best path to forward packets between networks. While routers, hubs, and switches now often combine functions, routers primarily connect and direct traffic between different networks, whereas hubs and switches operate within one network.
BASIC OF ROUTERS,ROUTER IOS AND ROUTING PROTOCOLSamiteshg
1. Routers are networking devices that connect different networks and forward data packets between them. They maintain routing tables to determine the best paths between networks.
2. The main functions of routers are packet forwarding, packet switching, and packet filtering. Routers examine packet headers to determine the best path using routing tables and switch packets between interfaces.
3. Common router operating systems are Cisco IOS and Juniper JUNOS. Cisco IOS is customized for Cisco devices and provides tools for management, memory allocation, and file storage. Juniper JUNOS offers a modular architecture and policy-based traffic controls.
This document discusses various interconnection devices used in modern networks. It describes network interface cards (NICs), repeaters, hubs, bridges, switches, and routers. NICs allow devices to connect to networks and have a unique MAC address. Repeaters amplify signals to extend distances between nodes. Hubs connect devices but are simple and not used in wireless networks. Bridges filter traffic between network segments. Switches inspect and forward data at the data link layer. Routers connect multiple networks as layer 3 gateways and use routing tables to filter incoming and outgoing traffic.
The document discusses TCP flow control using the sliding window protocol. It describes how the sliding window protocol allows multiple packets to be sent and confirmed with a single acknowledgment packet. This helps TCP dynamically adapt the transmission rate by reducing it during congestion and increasing it when congestion disappears. The size of the TCP window determines the number of acknowledgments sent during data transfer. The sliding window uses a congestion window and advertised window, where the congestion window sets the maximum number of outstanding segments and the advertised window is set by the receiver's buffer size.
Internet of Things (IoT) is a buzzword that is widely used in different domains. This talk explains the current state of the art in IoT (from a technological and research perspective), mainly in Europe. The future of IoT is promising and the trends in terms of number of devices and money involved show significant growth. There are still challenges in technical, business and social areas and some of them will be addressed in the talk.
The document discusses network layer concepts including packet switching, IP addressing, and fragmentation. It provides details on:
- Packet switching breaks data into packets that are routed independently and reassembled at the destination. This allows for more efficient use of bandwidth compared to circuit switching.
- IP addresses in IPv4 are 32-bit numbers that identify devices on the network. Addresses are expressed in decimal notation like 192.168.1.1. Fragmentation breaks packets larger than the MTU into smaller fragments for transmission.
This document discusses subnetting and IP addressing. It introduces subnet masks and how they are used to divide networks into subnets. Specific examples are provided on subnetting Class A, B, and C networks using subnet masks like /28, 255.255.255.192, and 255.255.240.0. The document also discusses calculating the number of subnets and valid hosts for different subnet masks. Multiple practice questions are provided at the end to help understand subnetting.
The Cisco Connected Roadways solution securely connects vehicles, infrastructure, and traffic management centers to improve safety, mobility and efficiency. It creates a wired and wireless network for vehicle-to-vehicle and vehicle-to-infrastructure communication to enable applications like traffic light control, smart parking, and traffic incident management. The solution components include onboard vehicle systems, roadside infrastructure, traffic management centers, and management platforms.
BASIC OF ROUTERS,ROUTER IOS AND ROUTING PROTOCOLSamiteshg
1. Routers are networking devices that connect different networks and forward data packets between them. They maintain routing tables to determine the best paths between networks.
2. The main functions of routers are packet forwarding, packet switching, and packet filtering. Routers examine packet headers to determine the best path using routing tables and switch packets between interfaces.
3. Common router operating systems are Cisco IOS and Juniper JUNOS. Cisco IOS is customized for Cisco devices and provides tools for management, memory allocation, and file storage. Juniper JUNOS offers a modular architecture and policy-based traffic controls.
This document discusses various interconnection devices used in modern networks. It describes network interface cards (NICs), repeaters, hubs, bridges, switches, and routers. NICs allow devices to connect to networks and have a unique MAC address. Repeaters amplify signals to extend distances between nodes. Hubs connect devices but are simple and not used in wireless networks. Bridges filter traffic between network segments. Switches inspect and forward data at the data link layer. Routers connect multiple networks as layer 3 gateways and use routing tables to filter incoming and outgoing traffic.
The document discusses TCP flow control using the sliding window protocol. It describes how the sliding window protocol allows multiple packets to be sent and confirmed with a single acknowledgment packet. This helps TCP dynamically adapt the transmission rate by reducing it during congestion and increasing it when congestion disappears. The size of the TCP window determines the number of acknowledgments sent during data transfer. The sliding window uses a congestion window and advertised window, where the congestion window sets the maximum number of outstanding segments and the advertised window is set by the receiver's buffer size.
Internet of Things (IoT) is a buzzword that is widely used in different domains. This talk explains the current state of the art in IoT (from a technological and research perspective), mainly in Europe. The future of IoT is promising and the trends in terms of number of devices and money involved show significant growth. There are still challenges in technical, business and social areas and some of them will be addressed in the talk.
The document discusses network layer concepts including packet switching, IP addressing, and fragmentation. It provides details on:
- Packet switching breaks data into packets that are routed independently and reassembled at the destination. This allows for more efficient use of bandwidth compared to circuit switching.
- IP addresses in IPv4 are 32-bit numbers that identify devices on the network. Addresses are expressed in decimal notation like 192.168.1.1. Fragmentation breaks packets larger than the MTU into smaller fragments for transmission.
This document discusses subnetting and IP addressing. It introduces subnet masks and how they are used to divide networks into subnets. Specific examples are provided on subnetting Class A, B, and C networks using subnet masks like /28, 255.255.255.192, and 255.255.240.0. The document also discusses calculating the number of subnets and valid hosts for different subnet masks. Multiple practice questions are provided at the end to help understand subnetting.
The Cisco Connected Roadways solution securely connects vehicles, infrastructure, and traffic management centers to improve safety, mobility and efficiency. It creates a wired and wireless network for vehicle-to-vehicle and vehicle-to-infrastructure communication to enable applications like traffic light control, smart parking, and traffic incident management. The solution components include onboard vehicle systems, roadside infrastructure, traffic management centers, and management platforms.
This document discusses routing protocols for vehicular ad hoc networks (VANETs). It begins with an introduction to VANETs and their applications. It then covers the main types of routing protocols for VANETs - position-based, topology-based, broadcast-based, cluster-based, and geocast-based. For each protocol type, it provides examples and discusses their advantages and disadvantages. It highlights issues like high node mobility and changing network topologies that make routing challenging in VANETs. In the end, it lists references for further reading on VANET routing protocols.
This document is a project report submitted by four students for their Bachelor of Engineering degree. It examines quality of service improvement in wireless sensor networks. Specifically, it studies cluster-based routing protocols like LEACH and proposes modifications to LEACH called MODLEACH that introduces efficient cluster head replacement and dual transmitting power levels. Thresholding techniques are also incorporated into MODLEACH to further boost performance based on metrics like throughput, network lifetime and cluster head formations. The report analyzes and compares the performance of LEACH, MODLEACH, MODLEACH with hard thresholds and MODLEACH with soft thresholds through simulation and implementation in Qualnet and Matlab.
The document discusses various IEEE 802 standards for networking technologies including Ethernet, wireless LAN (802.11), and their variants and evolutions over time. It provides details on Ethernet standards and implementations such as 802.3, 10BASE5, 10BASE2, 10BASE-T, 10BASE-F, Fast Ethernet, and Gigabit Ethernet. It also summarizes key aspects of wireless networking standards such as 802.11 components, frame format, and physical layer specifications including FHSS, DSSS, OFDM, and associated data rates and frequencies.
This document discusses IEEE 802.15.4 and Zigbee wireless communication standards. It provides an overview of 802.15.4, including its applications, characteristics, frequency bands, and MAC and PHY specifications. It also describes Zigbee's architecture and how it works with 802.15.4 at higher protocol layers to provide networking and routing functionality. Typical network topologies for 802.15.4 like star, peer-to-peer, and combined are also covered.
Enhanced Data rates for Global Evolution (EDGE)Ramrao Desai
Mobile users continue to demand higher data rates. With the continued growth in cellular services, laptop computer use and the Internet, wireless network providers are beginning to pay an increasing amount of attention to packet data networks. Enhanced Global Packet Radio Service (EGPRS) offers a substantial improvement in performance and capacity over existing GPRS services, in return for a relatively minimal additional investment. EGPRS, commonly called EDGE, achieves these enhancements to the GPRS system primarily by implementing changes to the Physical layer and to the Medium Access Control/Radio Link Control (MAC/RLC) layer. The significant improvements are a new modulation technique, additional modulation coding schemes, a combined Link Adaptation and Incremental Redundancy technique, re-segmentation of erroneously received packets, and a larger transmission window size.
Networking began in the 1960s when the US Department of Defense developed early computer networks to withstand a nuclear attack. The document then discusses the basics of networking including definitions of networking and common network types. It also explains the OSI model and its seven layers. Finally, it provides examples of DCS networks from Siemens and ABB that incorporate both Ethernet networks and high-speed serial networks to connect control system devices.
The document discusses the IEEE 802.15.4 standard and its limitations for Internet of Things applications with stringent requirements. It introduces the IEEE 802.15.4e standard, which amends the 802.15.4 MAC layer to enhance reliability, latency, bandwidth, and robustness against interference through the addition of new modes like DSME and TSCH. The document surveys the literature on these new modes and discusses open issues and how 802.15.4e helps enable critical IoT scenarios like smart cities and industrial settings.
Delay refers to the time taken to transfer a message from sender to receiver. It is calculated based on processing delay, queuing delay, transmission delay, and propagation delay. Packet loss occurs when a router's queue is full and it must drop packets. Bandwidth is the maximum rate of data transfer, while throughput is the actual rate of successful data transfer from one point to another.
1) Packet-switched networks necessarily constrain throughput, introduce delays, and can lose packets due to processing, queuing, transmission, and propagation delays at each node along the transmission path.
2) The total nodal delay at each node equals the processing delay plus the queuing delay plus the transmission delay plus the propagation delay.
3) End-to-end delay is calculated by summing the total nodal delays across all nodes between the source and destination.
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 summarizes a seminar presentation on WiMAX technology. It describes WiMAX as a wireless broadband technology based on the IEEE 802.16 standard that can provide internet access within a range of up to 31 miles. Key points covered include the basic components of a WiMAX system including towers and receivers, how WiMAX connections work, advantages over other technologies like speed and lack of wired infrastructure, and future applications like integrated laptop access. Issues discussed are the challenges of network deployment and lower costs compared to 3G mobile networks.
The document discusses congestion control in computer networks. It defines congestion as occurring when the load on a network is greater than the network's capacity. Congestion control aims to control congestion and keep the load below capacity. The document outlines two categories of congestion control: open-loop control, which aims to prevent congestion; and closed-loop control, which detects congestion and takes corrective action using feedback from the network. Specific open-loop techniques discussed include admission control, traffic shaping using leaky bucket and token bucket algorithms, and traffic scheduling.
This document discusses different types of networking devices used to connect local area networks (LANs). It describes hubs, repeaters, bridges, routers, and gateways. Hubs and repeaters operate at the physical layer, bridges operate at the physical and data link layers, and routers and gateways operate at the network layer and above to connect multiple networks and perform protocol conversion. The document provides details on the functions and characteristics of each type of device.
The document describes Cisco Network Academy's CCNA curriculum and Packet Tracer software. The CCNA curriculum validates skills in installing, configuring and troubleshooting medium-sized networks including WAN connections and basic security threats. Packet Tracer is a network simulation program used in the CCNA program to allow students to experiment with networks and troubleshoot issues. It supports simulation of network protocols, devices, and allows creation of network topologies to model real world networks.
The Sky X technology transparently enhances performance for users on a satellite network. It increases web performance by 3 times and file transfer speeds by 10 to 100 times by overcoming limitations of TCP protocols over satellite connections. The Sky X gateway replaces TCP with the Xpress Transport Protocol for the satellite link, improving throughput while remaining transparent to users and compatible with internet infrastructure. The Sky X system maximizes available bandwidth and is well-suited for satellite communication and remote network access.
Communication satellites orbit Earth and are used to transmit radio, television and other signals. The first artificial satellite was Sputnik 1, launched in 1957. There are different types of satellites including active satellites that amplify and retransmit signals, addressing disadvantages of early passive satellites. Geostationary satellites orbit at the same rate as Earth's rotation, allowing ground antennas to remain fixed. Other orbits include medium Earth orbit and low Earth orbit. VSAT systems use small ground terminals to communicate via satellite. GPS uses a constellation of satellites to provide location services worldwide.
Cse 318 Project Report on Goethe Institut Bangladesh Network DesignMaksudujjaman
1. The student designed a network for the Goethe-Institut in Dhaka to simulate their networking needs. The network included servers, PCs, wireless access points, switches, routers, IP phones, and other devices across three floors.
2. Physical and logical network diagrams were created showing the layout and connections between devices. Key features of the design included separate networks for each floor, wireless connectivity, remote device management, and security features.
3. A cost analysis was conducted calculating the total price of network devices, coming to a total of over 13 million BDT. Common network protocols like DNS, FTP, and SMTP were configured. The project taught the student about network concepts and skills in areas
This document summarizes different types of wide area network (WAN) connection technologies. It describes point-to-point technologies like T1 and T3 lines that provide dedicated bandwidth between two locations. It also discusses circuit-switched technologies like dial-up and ISDN that require call setup before transferring data, and packet-switched technologies like Frame-Relay and X.25 that share common infrastructure and are less expensive than dedicated lines but provide variable bandwidth. The document concludes that a WAN spans a large geographic area and typically connects two or more local area networks through public or private network transports.
Routers are network devices that connect different networks and direct data packets between them. They work at the network layer and use routing tables and routing protocols to determine the best path for packets to travel. There are different types of routers for different uses, such as broadband routers for homes/small offices, wireless routers, edge routers at the network boundary, and core routers that connect large networks at high speeds. Routers provide advantages like easily sharing an internet connection between devices and adding security, but also have disadvantages like complicated setup processes and adding data overhead.
Routers connect different computer networks and forward data packets between them by reading the address information in each packet to determine the ultimate destination. A router contains a routing table with information about connected networks and uses this to determine the best path for packets to travel through multiple networks to reach their destination. There are two main types of routers: core routers connect different cities while edge routers connect users and hosts to networks.
This document discusses routing protocols for vehicular ad hoc networks (VANETs). It begins with an introduction to VANETs and their applications. It then covers the main types of routing protocols for VANETs - position-based, topology-based, broadcast-based, cluster-based, and geocast-based. For each protocol type, it provides examples and discusses their advantages and disadvantages. It highlights issues like high node mobility and changing network topologies that make routing challenging in VANETs. In the end, it lists references for further reading on VANET routing protocols.
This document is a project report submitted by four students for their Bachelor of Engineering degree. It examines quality of service improvement in wireless sensor networks. Specifically, it studies cluster-based routing protocols like LEACH and proposes modifications to LEACH called MODLEACH that introduces efficient cluster head replacement and dual transmitting power levels. Thresholding techniques are also incorporated into MODLEACH to further boost performance based on metrics like throughput, network lifetime and cluster head formations. The report analyzes and compares the performance of LEACH, MODLEACH, MODLEACH with hard thresholds and MODLEACH with soft thresholds through simulation and implementation in Qualnet and Matlab.
The document discusses various IEEE 802 standards for networking technologies including Ethernet, wireless LAN (802.11), and their variants and evolutions over time. It provides details on Ethernet standards and implementations such as 802.3, 10BASE5, 10BASE2, 10BASE-T, 10BASE-F, Fast Ethernet, and Gigabit Ethernet. It also summarizes key aspects of wireless networking standards such as 802.11 components, frame format, and physical layer specifications including FHSS, DSSS, OFDM, and associated data rates and frequencies.
This document discusses IEEE 802.15.4 and Zigbee wireless communication standards. It provides an overview of 802.15.4, including its applications, characteristics, frequency bands, and MAC and PHY specifications. It also describes Zigbee's architecture and how it works with 802.15.4 at higher protocol layers to provide networking and routing functionality. Typical network topologies for 802.15.4 like star, peer-to-peer, and combined are also covered.
Enhanced Data rates for Global Evolution (EDGE)Ramrao Desai
Mobile users continue to demand higher data rates. With the continued growth in cellular services, laptop computer use and the Internet, wireless network providers are beginning to pay an increasing amount of attention to packet data networks. Enhanced Global Packet Radio Service (EGPRS) offers a substantial improvement in performance and capacity over existing GPRS services, in return for a relatively minimal additional investment. EGPRS, commonly called EDGE, achieves these enhancements to the GPRS system primarily by implementing changes to the Physical layer and to the Medium Access Control/Radio Link Control (MAC/RLC) layer. The significant improvements are a new modulation technique, additional modulation coding schemes, a combined Link Adaptation and Incremental Redundancy technique, re-segmentation of erroneously received packets, and a larger transmission window size.
Networking began in the 1960s when the US Department of Defense developed early computer networks to withstand a nuclear attack. The document then discusses the basics of networking including definitions of networking and common network types. It also explains the OSI model and its seven layers. Finally, it provides examples of DCS networks from Siemens and ABB that incorporate both Ethernet networks and high-speed serial networks to connect control system devices.
The document discusses the IEEE 802.15.4 standard and its limitations for Internet of Things applications with stringent requirements. It introduces the IEEE 802.15.4e standard, which amends the 802.15.4 MAC layer to enhance reliability, latency, bandwidth, and robustness against interference through the addition of new modes like DSME and TSCH. The document surveys the literature on these new modes and discusses open issues and how 802.15.4e helps enable critical IoT scenarios like smart cities and industrial settings.
Delay refers to the time taken to transfer a message from sender to receiver. It is calculated based on processing delay, queuing delay, transmission delay, and propagation delay. Packet loss occurs when a router's queue is full and it must drop packets. Bandwidth is the maximum rate of data transfer, while throughput is the actual rate of successful data transfer from one point to another.
1) Packet-switched networks necessarily constrain throughput, introduce delays, and can lose packets due to processing, queuing, transmission, and propagation delays at each node along the transmission path.
2) The total nodal delay at each node equals the processing delay plus the queuing delay plus the transmission delay plus the propagation delay.
3) End-to-end delay is calculated by summing the total nodal delays across all nodes between the source and destination.
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 summarizes a seminar presentation on WiMAX technology. It describes WiMAX as a wireless broadband technology based on the IEEE 802.16 standard that can provide internet access within a range of up to 31 miles. Key points covered include the basic components of a WiMAX system including towers and receivers, how WiMAX connections work, advantages over other technologies like speed and lack of wired infrastructure, and future applications like integrated laptop access. Issues discussed are the challenges of network deployment and lower costs compared to 3G mobile networks.
The document discusses congestion control in computer networks. It defines congestion as occurring when the load on a network is greater than the network's capacity. Congestion control aims to control congestion and keep the load below capacity. The document outlines two categories of congestion control: open-loop control, which aims to prevent congestion; and closed-loop control, which detects congestion and takes corrective action using feedback from the network. Specific open-loop techniques discussed include admission control, traffic shaping using leaky bucket and token bucket algorithms, and traffic scheduling.
This document discusses different types of networking devices used to connect local area networks (LANs). It describes hubs, repeaters, bridges, routers, and gateways. Hubs and repeaters operate at the physical layer, bridges operate at the physical and data link layers, and routers and gateways operate at the network layer and above to connect multiple networks and perform protocol conversion. The document provides details on the functions and characteristics of each type of device.
The document describes Cisco Network Academy's CCNA curriculum and Packet Tracer software. The CCNA curriculum validates skills in installing, configuring and troubleshooting medium-sized networks including WAN connections and basic security threats. Packet Tracer is a network simulation program used in the CCNA program to allow students to experiment with networks and troubleshoot issues. It supports simulation of network protocols, devices, and allows creation of network topologies to model real world networks.
The Sky X technology transparently enhances performance for users on a satellite network. It increases web performance by 3 times and file transfer speeds by 10 to 100 times by overcoming limitations of TCP protocols over satellite connections. The Sky X gateway replaces TCP with the Xpress Transport Protocol for the satellite link, improving throughput while remaining transparent to users and compatible with internet infrastructure. The Sky X system maximizes available bandwidth and is well-suited for satellite communication and remote network access.
Communication satellites orbit Earth and are used to transmit radio, television and other signals. The first artificial satellite was Sputnik 1, launched in 1957. There are different types of satellites including active satellites that amplify and retransmit signals, addressing disadvantages of early passive satellites. Geostationary satellites orbit at the same rate as Earth's rotation, allowing ground antennas to remain fixed. Other orbits include medium Earth orbit and low Earth orbit. VSAT systems use small ground terminals to communicate via satellite. GPS uses a constellation of satellites to provide location services worldwide.
Cse 318 Project Report on Goethe Institut Bangladesh Network DesignMaksudujjaman
1. The student designed a network for the Goethe-Institut in Dhaka to simulate their networking needs. The network included servers, PCs, wireless access points, switches, routers, IP phones, and other devices across three floors.
2. Physical and logical network diagrams were created showing the layout and connections between devices. Key features of the design included separate networks for each floor, wireless connectivity, remote device management, and security features.
3. A cost analysis was conducted calculating the total price of network devices, coming to a total of over 13 million BDT. Common network protocols like DNS, FTP, and SMTP were configured. The project taught the student about network concepts and skills in areas
This document summarizes different types of wide area network (WAN) connection technologies. It describes point-to-point technologies like T1 and T3 lines that provide dedicated bandwidth between two locations. It also discusses circuit-switched technologies like dial-up and ISDN that require call setup before transferring data, and packet-switched technologies like Frame-Relay and X.25 that share common infrastructure and are less expensive than dedicated lines but provide variable bandwidth. The document concludes that a WAN spans a large geographic area and typically connects two or more local area networks through public or private network transports.
Routers are network devices that connect different networks and direct data packets between them. They work at the network layer and use routing tables and routing protocols to determine the best path for packets to travel. There are different types of routers for different uses, such as broadband routers for homes/small offices, wireless routers, edge routers at the network boundary, and core routers that connect large networks at high speeds. Routers provide advantages like easily sharing an internet connection between devices and adding security, but also have disadvantages like complicated setup processes and adding data overhead.
Routers connect different computer networks and forward data packets between them by reading the address information in each packet to determine the ultimate destination. A router contains a routing table with information about connected networks and uses this to determine the best path for packets to travel through multiple networks to reach their destination. There are two main types of routers: core routers connect different cities while edge routers connect users and hosts to networks.
Router is a networking device that connects different networks and selects the best path to forward packets between them. It operates at the network layer of the OSI model. Cisco is the leading router manufacturer, making 70% of the market. Routers come in different sizes for different uses - access routers for small networks, distribution routers for ISPs, and core routers for backbone networks. Static routing requires manually configuring routes, while dynamic routing uses protocols to share route information between routers automatically.
Report on cloud computing by prashant guptaPrashant Gupta
The document is a technical seminar report submitted by Prashant Gupta on cloud computing. It includes an abstract, introduction, table of contents, and initial sections on the concept and history of cloud computing. The introduction provides a definition of cloud computing and discusses the shift from centralized to distributed computing models. It highlights the scalability and on-demand access to computing resources that cloud computing provides.
A router is a networking device that forwards data packets between computer networks. It has multiple network interfaces and uses information in routing tables to determine the best path to direct each packet. As a packet comes in one of its lines, the router reads the address and uses its routing information to determine the next network. This allows it to effectively direct traffic through multiple interconnected networks until packets reach their destination. Router technology has evolved alongside increases in network bandwidth, allowing networks to expand while also driving down costs over time.
Routing protocols allow routers to communicate and exchange information that helps determine the best path between networks. The main types are static routing, where routes are manually configured, and dynamic routing, where routes are automatically updated as network conditions change. Common dynamic routing protocols include RIP, IGRP, EIGRP, and OSPF, which use different algorithms and metrics like hop count or bandwidth to calculate the best routes.
The document discusses the key components of a computer network and how information flows through it. It identifies the hardware required, including computer workstations, Ethernet cables, switches or hubs, routers, servers, and the internet. It explains that computer workstations connect to the network via Ethernet cables, and information flows from there through switches or hubs and routers, which direct the information either to the internet or main server for storage. The local area network (LAN) refers to connected computers and devices within an organization, while a wide area network (WAN) connects devices across the world, such as the internet.
El documento proporciona información reciente sobre la inversión extranjera directa en México y en el mundo. Reporta que en 2012 México recibió 12,659.4 millones de dólares en IED, 34.9% menos que en 2011. Los principales países proveedores de IED a México fueron Estados Unidos, Japón, Canadá, Alemania y Países Bajos. La IED se destinó principalmente al sector manufacturero. También presenta cifras sobre el PIB de México, la balanza de pagos y expectativas de IED y PIB para
This document discusses how to effectively use the Spring framework in Liferay. It explains that Spring handles infrastructure and allows focusing on unique functionality. It also describes how Liferay uses Spring in many of its modules through services, Hibernate, workflows and more. Additionally, it notes pros like easy use of annotations and submodules, as well as cons like different contexts for ServiceBuilder and Spring MVC requiring use of utilization methods.
An Insight into Internal Cross Functional Stakeholder Engagement. References from Online data & my professional experience of 14 Years in various roles
EDGE, HSPA, LTE: The Mobile Broadband Advantageeanimou
This document provides an overview of mobile broadband technologies including EDGE, HSPA, LTE and competing technologies. Key points:
1) GSM/UMTS networks using HSPA have seen widespread global deployment and will continue to comprise the majority of subscribers for the next 5-10 years.
2) HSPA Evolution enhances HSPA and provides higher spectral efficiency than competing technologies like WiMAX and EV-DO Rev. B.
3) LTE specifications are nearing completion and the 3GPP approach matches or exceeds other OFDMA systems. LTE deployment will begin in 2009.
4) The 3GPP roadmap allows flexible evolution from GSM to UMTS
This document summarizes some key features of the LTE radio interface that enable unprecedented performance in mobile broadband. It discusses features like spectrum flexibility that allow LTE to operate in different frequency bands and bandwidths with both FDD and TDD duplexing. It also describes multi-antenna transmission techniques in LTE including transmit diversity to improve coverage and capacity, and multi-stream transmission to significantly increase peak data rates through multiple parallel data streams. Scheduling, link adaptation, and hybrid ARQ are explained as ways to efficiently utilize radio resources based on varying channel conditions.
This document summarizes a seminar report on cluster computing. The report discusses cluster components including applications, middleware, operating systems, interconnects, and nodes. It describes different types of clusters such as high availability clusters, load balancing clusters, and high performance clusters. It highlights advantages like high processing capacity and disadvantages like increased difficulty of management. It provides examples of cluster applications such as Google search engines, petroleum simulation, protein exploration, and earthquake simulation.
China's soil pollution is widespread and poses health risks. A government study found 19.4% of China's farmland is contaminated by heavy metals and toxins from industrial pollution and pesticide overuse. Farmers and residents near polluted fields report high rates of illness. Toxic cadmium levels have been found in rice crops, threatening food safety. While China has acknowledged the problem, addressing widespread soil remediation will be difficult and take decades.
The document discusses electromagnetic bombs (e-bombs) and their potential effects. It summarizes that e-bombs could disable modern technology and cripple infrastructure by inducing powerful electromagnetic pulses. The document outlines existing technologies like flux compression generators and virtual cathode oscillators that could potentially be used to build e-bombs. It notes that e-bombs could couple electromagnetic energy into electronic systems through antennae or wiring to potentially damage computers and disrupt communications networks on a large scale.
1) An EMP attack from a high-altitude nuclear detonation could have a catastrophic impact on the US by disrupting critical infrastructure systems.
2) The document assesses that the electric power grid, telecommunications, transportation, and other infrastructure sectors are highly vulnerable to EMP and interdependent, so that the failure of one could collapse others.
3) Recovery from a major EMP attack that causes wide-scale infrastructure damage could take months or years due to difficulties obtaining replacement parts and lack of spare equipment for critical systems like large power transformers.
An electromagnetic pulse (EMP) bomb, or E-bomb, is a non-lethal weapon that uses electromagnetic pulses to disable electrical circuitry within a radius. It works by generating an intense electromagnetic field from a flux compression generator powered by an explosive charge. This pulse induces surges in electronics that overwhelm and destroy semiconductor devices. E-bombs could knock out power grids and communication systems over a large area but spare human life. While useful for disabling infrastructure, E-bombs have limitations in accuracy and risk harming medical devices. Protection requires hardening sites and equipment against EMP effects.
The document discusses routing protocol attacks against routers. It provides an overview of common routing protocols like RIP, OSPF, BGP and CDP. It then describes different attacks against these protocols like spoofing, injection of malformed packets, autonomous system scanning and denial of service attacks. The document emphasizes the need for safeguards like disabling unnecessary protocols, implementing authentication and filtering to protect against routing protocol attacks.
MS SQL Server is a database server produced by Microsoft that enables users to write and execute SQL queries and statements. SQL includes data definition language (DDL) statements to define and modify database schemas and data manipulation language (DML) statements to manipulate database content. Common DDL commands include CREATE TABLE, ALTER TABLE, and DROP TABLE. Common DML commands are INSERT to add rows, UPDATE to modify rows, and DELETE to remove rows. SQL statements also include clauses like WHERE, GROUP BY, and ORDER BY to filter and sort query results.
The document is a seminar report submitted by Ganesh B. Dhage to the Department of Computer Engineering at RMD Sinhgad School of Engineering in partial fulfillment of the requirements for a degree in computer engineering. It discusses CAPTCHA security and is guided by Prof. Vaibhav Dhore. The report includes an introduction to CAPTCHAs, different types of CAPTCHAs such as text, graphic, and audio CAPTCHAs. It also discusses constructing, breaking, and issues with CAPTCHAs.
A hub, switch, and router each serve different functions in a network. A hub simply connects devices together but broadcasts all data to all ports. A switch connects devices and sends data only to the port of the intended recipient to avoid congestion. A router connects multiple networks together, both wired and wireless, and chooses the best path to send data packets between the networks.
This document discusses different networking devices including hubs, switches, routers, bridges, and brouters. It provides information on their functions, design, and operation at both the physical and data link layers of the OSI model. It also discusses IP addresses and their role in identifying devices and enabling communication using the Internet Protocol.
Network connecting devices and their securitylovizabasharat
Networking devices such as hubs, switches, routers, and gateways are used to connect electronic devices and share files and resources over a local area network (LAN). Hubs connect multiple devices but do not filter traffic. Switches are more intelligent and can identify devices to deliver messages only to the intended recipient. Routers connect different networks and choose congestion-free paths. Gateways connect incompatible networks by translating between protocols. Other devices like bridges, brouters, repeaters, modems, access points, and network interface cards (NICs) help devices connect either via wired or wireless connections. Network security devices such as firewalls, virtual private networks (VPNs), and intrusion detection/prevention systems (IDS
This document contains lecture notes on data communication from Abul Kalam Robin dated September 10, 2021. It covers topics such as data communication, internet connections, data transmission modes, network types, network devices, network addressing, OSI and TCP/IP models, digital modulation, signals, broadband vs baseband transmission, transmission impairments, line coding, and encapsulation/de-capsulation. The notes are divided into multiple classes that progress from basic concepts to more advanced topics in computer networking.
Network hardware devices mediate data transfer within computer networks. Common basic networking devices include routers, bridges, switches, hubs, and repeaters. Routers connect similar networks, bridges connect similar network segments, switches manage bandwidth, hubs provide connection points, and repeaters extend network length. Hybrid devices include protocol converters, bridge routers, and digital media receivers. Other hardware like modems and network cards establish network or dial-up connections.
A computer network consists of several components that allow data transfer between devices. There are three categories of network components: end devices like computers and printers, intermediary devices like switches and routers, and network media like cables. A network interface card allows a computer to connect to a network by providing a dedicated network connection. Repeaters amplify signals to extend network coverage but cannot connect different networks or reduce traffic. Switches operate at the data link layer and send data frames to specific ports, while routers operate at the network layer and forward packets using routing tables. Gateways connect networks using different protocols by acting as protocol converters.
This document discusses different types of networking devices including hubs, repeaters, switches, modems, and routers. It provides details on what each device is used for, advantages and disadvantages. Hubs connect multiple devices but don't reduce collisions. Repeaters extend network distance but can't connect different architectures. Switches segment networks to reduce collisions. Modems convert digital to analog signals for transmission. Routers connect different network types and choose optimal paths but are more expensive than other devices.
Networking devices like repeaters, hubs, bridges, routers, switches, and gateways are used to connect nodes and networks. Repeaters extend network distance by boosting signals. Hubs connect workstations into a LAN by resending data frames to all ports. Bridges are more intelligent repeaters that examine MAC addresses to form tables. Routers operate at the network layer, can connect similar and dissimilar networks, and determine the shortest route between destinations. Switches form dedicated connections between ports like bridges but have multiple ports. Gateways link all seven layers of the OSI model when networks differ at any layer, primarily handling email protocols.
This document discusses different types of internetworking devices used to connect local area networks (LANs). It describes hubs, bridges, switches and routers in increasing order of complexity. Hubs simply repeat and broadcast data to all ports, while bridges learn and filter traffic between connected LANs. Switches operate similarly to bridges but provide dedicated connections for each workstation. Routers connect distinct networks like a LAN to the Internet, and make routing decisions based on IP addresses. The document outlines reasons for interconnecting LANs and the functions of various internetworking devices.
The difference between a hub, switch and router webopediaHarikiran Raju
A hub replicates all data received on one port to all other ports, potentially slowing the network. A switch only sends data to the destination port to improve efficiency. A router connects multiple networks and determines the best path to send data between them using protocols like ICMP. Modern routers integrate switching, routing, security and other functions into one device.
This document discusses various components of backbone networks including bridges, routers, and gateways. It describes common backbone architectures like serial, distributed, and collapsed backbones. Key technologies discussed include Ethernet, FDDI, and ATM. The document provides details on improving backbone performance through techniques like upgrading network components, increasing circuit capacity, and reducing network demand. It recommends designing backbones that can be easily upgraded and moving to Ethernet as the standard technology for both LANs and backbones.
difference between hub, bridge, switch and routerAkmal Cikmat
An additional information that might be useful for Computing/Computer Science students especially.
made this as a homework assigned to me.
Hope this may be the thing that you've been looking for
Routers are networking devices that forward data packets between computer networks by reading the address information in each packet and determining the ultimate destination. Routers then use information in their routing tables to direct each packet to the next network on its journey until it reaches its destination. Common types of routers include broadband routers for homes/small offices, wireless routers that create wireless signals, core routers for internet backbones, and edge routers that provide access points to core networks. Routers work at the network layer and use routing protocols to share information and select the best paths between networks.
Network components include computers, cables, network interface cards, switches, and network operating systems. Multicast involves one or more senders and recipients sharing data traffic between unicast and broadcast. An intranet connects PCs within an organization privately, while the internet connects computers globally using TCP/IP. Active hubs boost and relay signals with their own power supply, and passive hubs rely on an active hub for power. Gateways connect different network protocols, and access points provide wireless connectivity to wired networks. Routers route data packets between networks or subnets. Modems convert digital signals to analog for telephone line transmission. Network topology refers to the arrangement of nodes and connections in a network.
Routers are networking devices that forward packets between logical networks. They are used to extend or segment large internetworks and connect TCP/IP networks and local area networks to the Internet. Routers have advanced features for quality of service, traffic filtering, and encryption. Switches offer intelligence beyond basic hubs and can read MAC addresses to selectively forward frames to specific ports. Bridges divide a network into segments and filter traffic between segments based on MAC addresses. Gateways connect networks that use different protocols by operating at the network layer.
The document discusses various networking devices and their functions:
- Hubs broadcast messages to all connected devices, using more bandwidth than switches. Switches only send messages to the targeted device.
- Bridges divide larger networks and manage data flow between segments by examining MAC addresses.
- Routers route data between network segments by reading packet headers to determine destinations.
- Gateways translate between different data formats but not the data itself.
- Other devices discussed include wireless access points, modems, firewalls, network interface cards, and devices for specific media like fiber optics.
A hub is a networking device that connects multiple devices on a local area network (LAN). It receives data packets through one port and broadcasts them to all other ports so all connected devices can see the packets. Hubs operate in half duplex mode and have no bandwidth management or collision detection. Switches are more advanced devices that can connect more devices than hubs. Switches have buffers and port-to-MAC address tables that allow them to send frames to specific ports faster than hubs. Routers connect multiple networks like LANs and WANs. Routers use IP addresses to route packets between networks and can run routing protocols to dynamically learn routes.
Network devices like hubs, switches, and routers connect computers in a network and help manage traffic flow. Hubs broadcast all received data to all ports but have limited bandwidth. Switches can connect more devices than hubs and have features like VLANs. Routers connect different networks and use IP addresses to direct traffic. Other devices like firewalls, VPNs, and IDS/IPS provide network security functions.
The document discusses network infrastructure management and provides details on networking devices and concepts. It covers networking scenarios and infrastructure, commonly used devices like switches, hubs, routers, and wireless devices, and cable types. Specific sections are devoted to explaining switches, routers, VPNs, modems and their classifications. Wireless technologies like WiFi, Bluetooth, and WiMax are also summarized.
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Chandan singh seminar report pdf.......router
1. ROUTER
BBDNIIT Page 1
ACKNOWLEDGEMENT
I wish to extend my sincere gratitude to my seminar guide, Ms. Sonam Singh
Lecturer, Department of Electronics & Communication, for her valuable
guidance and encouragement which has been absolutely helpful in successful
completion of this seminar.
I am indebted to Prof. Poonam Pathak, Professor and Head, Department of
Electronics & Communication for her valuable support.
I am also grateful to my parents and friends for their timely aid without which I
wouldn’t have finished my seminar successfully. I extend my thanks to all my
well-wishers and all those who have contributed directly and indirectly for the
completion of this work.
And last but not the least; I thank God Almighty for his blessings without which
the completion of this seminar would not have been Possible
2. ROUTER
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ABSTRACT
This seminar discusses the basic concepts of Router.Basically A router is a
device that forwards data packets between computer networks, creating an
overlay internetwork. A router is connected to at least two networks,
commonly two LANs or WANs or a LAN and its ISP's network. Routers are
located at gateways, the places where two or more networks connect.
Various types of Router such as Broadband router,Wireless router,Core router
etc are also discussed in this report.Alongwith this it also includes the
components of router such as motherboard,CPU,Memory etc.It also describes
its various functions,advantages & disadvantages.
Besides this basic concepts of hubs,switches,delivering,forwarding & routing
are also discussed
3. ROUTER
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INDEX
1. Acknowledgement 01
2. Abstract 02
3. Index 03
4. Introduction 05
5. Router 06
6. Symbol Of Router 07
7. Difference between Hubs ,Switches & Router 09
8.Delivery,Forwarding & Routing 13
8.1 Delivery
8.2 Forwarding
8.3 Routing
9.Router and the network layer 16
10.Types of Router 18
10.1 Broadband Router
10.2 Wireless Router
10.3 Edge Router
10.4 Core Router
11. Functions of Router 23
11.1 Restrict Broadcasts to the LAN
11.2 Act as the Default Gateway
11.3 Move (route) Data between Networks
11.4 Learn and Advertise Loop-Free Paths
4. ROUTER
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12. Router Component 26
12.1 Router Motherboard
12.2 Router CPU
12.3 RAM
12.4 NVRAM
12.5 Flash Memory
12.6 ROM
13. Applications of Router 29
13.1 Access
13.2 Distribution
13.3 Security
13.4 Core
14. Advantages of Router 33
15. Disadvantages of Router 34
16. Conclusion 35
17. Bibiliography 36
5. ROUTER
BBDNIIT Page 5
INTRODUCTION
Firstly we understand the concept of what is broadband connection in
communication networks. Broadband is a high-capacity high-speed Data
transmission medium. This can be done on a single cable by establishing
different bandwidth channels. Broadband technology can be used to transmit
voice, data and video over long distances simultaneously.
Routers capture the information that come though broadband connection via a
modemvand deliver it to your computer. The router choose route for the
packet so that you receive the information firstly. Routers and multiport
devices and more sophisticated as compared to repeaters and brigdes.
Router s also support filtering and encapsulation like bridges. They operate at
physical data link and network layer of OSI model. Like bridges they are self
learning. As they can communicate their existence to other devices and can
learn of the existence of new routers. Nodes and LAN segments.
A router has access to the network layer address or logical address (IP
address) it contains a routing table that enables it to make decisions about the
route i.e. to determine which of several possible paths between the source
and destination is the best for a particular transmission. These routing tables
are dynamic are updated using routing protocols.
The router receive the packets from one connected network and pass them to
asecond connected network. However if a received packet contains the
address of a node that is on sone other network (of which the router is not a
member). The router determines which of its connected networks is the best
next relay point for that packet. Once the router has identified the best rout for
a packet to travel. It passes the packet along the appropriate network to
another router.
6. ROUTER
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ROUTER
A router is a device that forwards data packets between computer networks,
creating an overlay internetwork. A router is connected to at least two
networks, commonly two LANs or WANs or a LAN and its ISP's network.
Routers are located at gateways, the places where two or more networks
connect.
Routers use headers and forwarding tables to determine the best path for
forwarding the packets, and they use protocols such as ICMP to communicate
with each other and configure the best route between any two hosts.
When a data packet comes in one of the lines, the router reads the address
information in the packet to determine its ultimate destination. Then, using
information in its routing table or routing policy, it directs the packet to the next
network on its journey. Routers perform the "traffic directing" functions on
the Internet. A data packet is typically forwarded from one router to another
through the networks that constitute the internetwork until it reaches its
destination node
7. ROUTER
BBDNIIT
The most familiar type of routers are
pass data, such as web pages, email, IM, and videos between the home
computers and the Internet. An example of a router would be the
owner's cable or DSL modem
More sophisticated routers, such as enterprise routers, connect large
business or ISP networks up to the powerful
high speed along the
routers are typically dedicated hardware devices, use of software
routers has grown increasingly common.
SYMBOL OF ROUTER
The most familiar type of routers are home and small office routers
pass data, such as web pages, email, IM, and videos between the home
computers and the Internet. An example of a router would be the
DSL modem, which connects to the Internet through an
More sophisticated routers, such as enterprise routers, connect large
business or ISP networks up to the powerful core routers that forw
optical fiber lines of the Internet backbone
e typically dedicated hardware devices, use of software
routers has grown increasingly common.
SYMBOL OF ROUTER
Page 7
home and small office routers that simply
pass data, such as web pages, email, IM, and videos between the home
computers and the Internet. An example of a router would be the
, which connects to the Internet through an ISP.
More sophisticated routers, such as enterprise routers, connect large
that forward data at
Internet backbone. Though
e typically dedicated hardware devices, use of software-based
9. ROUTER
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DIFFERENCE BETWEEN HUB, SWITCH & ROUTER
The functions of the three devices are all quite different from one another,
even if at times they are all integrated into a single device. Which one do you
use when? Let's take a look...
HUB
A common connection point for devices in a network. Hubs are commonly
used to connect segments of a LAN. A hub contains multiple ports. When
a packet arrives at one port, it is copied to the other ports so that all segments
of the LAN can see all packets.
SWITCH
In networks, a device that filters and forwards packets between LAN
segments. Switches operate at the data link layer (layer 2) and sometimes
the network layer (layer 3) of the OSI Reference Model and
10. ROUTER
BBDNIIT
therefore support any packet protocol. LANs that use switches to
join segments are called switched LANs or, in the case of
switched Ethernet LANs.
ROUTER
A device that forwards data
at least two networks, commonly two
its ISP.s network. Routers are located at
more networks connect. Routers use
determine the best path for forwarding the pa
use protocols such as ICMP
the best route between any two hosts.
Today most routers have become something of a Swiss Army knife,
combining the features and functionality of a router and switch/hub into a
single unit. So conversations regarding these d
especially to someone new to computer networking.
The functions of a router, hub and a switch are all quite different from one
another, even if at times they are all integrated into a single
with the hub and the switch since these
network
Each serves as a central connection for all of your network equipment and
handles a data type known as frames. Frames carry your data. When a frame
any packet protocol. LANs that use switches to
are called switched LANs or, in the case of Ethernet networks,
switched Ethernet LANs.
data packets along networks. A router is connected to
at least two networks, commonly two LANs or WANs or a LAN and
network. Routers are located at gateways, the places where two or
more networks connect. Routers use headers and forwarding tables to
determine the best path for forwarding the packets, and they
ICMP to communicate with each other and configure
the best route between any two hosts.
ers have become something of a Swiss Army knife,
combining the features and functionality of a router and switch/hub into a
single unit. So conversations regarding these devices can be a bit misleading
especially to someone new to computer networking.
functions of a router, hub and a switch are all quite different from one
another, even if at times they are all integrated into a single device
with the hub and the switch since these two devices have similar roles on the
Each serves as a central connection for all of your network equipment and
handles a data type known as frames. Frames carry your data. When a frame
Page 10
any packet protocol. LANs that use switches to
Ethernet networks,
. A router is connected to
or a LAN and
, the places where two or
and forwarding tables to
ckets, and they
to communicate with each other and configure
ers have become something of a Swiss Army knife,
combining the features and functionality of a router and switch/hub into a
evices can be a bit misleading
functions of a router, hub and a switch are all quite different from one
device. Let's start
two devices have similar roles on the
Each serves as a central connection for all of your network equipment and
handles a data type known as frames. Frames carry your data. When a frame
11. ROUTER
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is received, it is amplified and then transmitted on to the port of the destination
PC. The big difference between these two devices is in the method in which
frames are being delivered.
In a hub, a frame is passed along or "broadcast" to every one of its ports. It
doesn't matter that the frame is only destined for one port. The hub has no
way of distinguishing which port a frame should be sent to. Passing it along to
every port ensures that it will reach its intended destination. This places a lot
of traffic on the network and can lead to poor network response times.
Additionally, a 10/100Mbps hub must share its bandwidth with each and every
one of its ports. So when only one PC is broadcasting, it will have access to
the maximum available bandwidth. If, however, multiple PCs are
broadcasting, then that bandwidth will need to be divided among all of those
systems, which will degrade performance.
A switch, however, keeps a record of the MAC addresses of all the devices
connected to it. With this information, a switch can identify which system is
sitting on which port. So when a frame is received, it knows exactly which port
to send it to, without significantly increasing network response times. And,
unlike a hub, a 10/100Mbps switch will allocate a full 10/100Mbps to each of
its ports. So regardless of the number of PCs transmitting, users will always
have access to the maximum amount of bandwidth. It's for these reasons why
a switch is considered to be a much better choice then a hub.
Routers are completely different devices. Where a hub or switch is concerned
with transmitting frames, a router's job, as its name implies, is to
route packets to other networks until that packet ultimately reaches its
destination. One of the key features of a packet is that it not only contains
data, but the destination address of where it's going.
A router is typically connected to at least two networks, commonly two Local
Area Networks (LANs) or Wide Area Networks (WAN) or a LAN and its ISP's
12. ROUTER
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network . for example, your PC or workgroup and EarthLink. Routers are
located at gateways, the places where two or more networks connect.
Today, a wide variety of services are integrated into most broadband routers.
A router will typically include a 4 - 8 port Ethernet switch (or hub) and a
Network Address Translator (NAT). In addition, they usually include a
Dynamic Host Configuration Protocol (DHCP) server, Domain Name Service
(DNS) proxy server and a hardware firewall to protect the LAN from malicious
intrusion from the Internet.
All routers have a WAN Port that connects to a DSL or cable modem for
broadband Internet service and the integrated switch allows users to easily
create a LAN. This allows all the PCs on the LAN to have access to the
Internet and Windows file and printer sharing services.
Routers might have a single WAN port and a single LAN port and are
designed to connect an existing LAN hub or switch to a WAN. Ethernet
switches and hubs can be connected to a router with multiple PC ports to
expand a LAN. Depending on the capabilities (kinds of available ports) of the
router and the switches or hubs, the connection between the router and
switches/hubs may require either straight-thru or crossover (null-modem)
cables. Some routers even have USB ports, and more commonly, wireless
access points built into them.
Some of the more high-end or business class routers will also incorporate a
serial port that can be connected to an external dial-up modem, which is
useful as a backup in the event that the primary broadband connection goes
down, as well as a built in LAN printer server and printer port.
13. ROUTER
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DELIVERY, FORWARDING & ROUTING
DELIVERY
The network layer supervises the handling of the packets by the underlying
physical networks. We define this handling as the delivery of a packet.
o Direct Datagram Deliveries: When datagrams are sent between two
devices on the same physical network, it is possible for datagrams to be
delivered directly from the source to the destination. Imagine that you want
to deliver a letter to a neighbor on your street. You probably wouldn't
bother mailing it through the post office; you'd just put the neighbor’s name
on the envelope and stick it right into his or her mailbox.
o Indirect Datagram Deliveries: When two devices are not on the same
physical network, the delivery of datagrams from one to the other
is indirect. Since the source device can't see the destination on its local
network, it must send the datagram through one or more intermediate
devices to deliver it. Indirect delivery is analogous to mailing a letter to a
friend in a different city. You don't deliver it yourself—you put it into the
postal system. The letter journeys through postal system, possibly taking
several intermediate steps, and ends up in your friend's neighborhood,
where a postal carrier puts it into his or her mailbox.
FORWARDING
o For pure Internet Protocol (IP) forwarding function, a router is designed to
minimize the state information associated with individual packets. The
main purpose of a router is to connect multiple networks and forward
packets destined either for its own networks or other networks. A router is
considered aLayer 3 device because its primary forwarding decision is
based on the information in the Layer 3 IP packet, specifically the
destination IP address. This process is known as routing. When each
router receives a packet, it searches its routing table to find the best match
between the destination IP address of the packet and one of the network
addresses in the routing table. Once a match is found, the packet is
encapsulated in the Layer 2 data link frame for that outgoing interface. A
14. ROUTER
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router does not look into the actual data contents that the packet carries,
but only at the layer 3 addresses to make a forwarding decision, plus
optionally other information in the header for hints on, for example, quality
of service (QoS).
o Forwarding decisions can involve decisions at layers other than layer 3. A
function that forwards based on layer 2 information is properly called
a bridge. This function is referred to as layer 2 bridging, as the addresses
it uses to forward the traffic are layer 2 addresses (e.g. MAC
addresses on Ethernet).
o Besides making decision as to which interface a packet is forwarded to,
which is handled primarily via the routing table, a router also has to
manage congestion, when packets arrive at a rate higher than the router
can process. Three policies commonly used in the Internet are tail
drop, random early detection (RED), and weighted random early
detection (WRED). Tail drop is the simplest and most easily implemented;
the router simply drops packets once the length of the queue exceeds the
size of the buffers in the router. RED probabilistically drops datagrams
early when the queue exceeds a pre-configured portion of the buffer, until
a pre-determined max, when it becomes tail drop. WRED requires a
weight on the average queue size to act upon when the traffic is about to
exceed the pre-configured size, so that short bursts will not trigger random
drops.
o Another function a router performs is to decide which packet should be
processed first when multiple queues exist.
ROUTING
Routing is the process of selecting best paths in a network. In the past, the
term routing was also used to mean forwarding network traffic among
networks. However this latter function is much better described as simply
forwarding. Routing is performed for many kinds of networks, including
the telephone network (circuit switching), electronic data networks (such as
15. ROUTER
BBDNIIT Page 15
the Internet), andtransportation networks. This article is concerned primarily
with routing in electronic data networks using packet switching technology.
In packet switching networks, routing directs packet forwarding (the transit of
logically addressed network packets from their source toward their ultimate
destination) through intermediate nodes. Intermediate nodes are typically
network hardware devices such as routers, bridges, gateways, firewalls,
or switches. General-purpose computers can also forward packets and
perform routing, though they are not specialized hardware and may suffer
from limited performance. The routing process usually directs forwarding on
the basis of routing tables which maintain a record of the routes to various
network destinations. Thus, constructing routing tables, which are held in the
router's memory, is very important for efficient routing. Most routing algorithms
use only one network path at a time. Multipath routing techniques enable the
use of multiple alternative paths.
In case of overlapping/equal routes, the following elements are considered in
order to decide which routes get installed into the routing table (sorted by
priority):
• Prefix-Length: where longer subnet masks are preferred (independent of
whether it is within a routing protocol or over different routing protocol).
• Metric: where a lower metric/cost is preferred (only valid within one and
the same routing protocol).
• Administrative distance: where a lower distance is preferred (only valid
between different routing protocols)
Routing, in a more narrow sense of the term, is often contrasted
with bridging in its assumption that network addresses are structured and that
similar addresses imply proximity within the network. Structured addresses
allow a single routing table entry to represent the route to a group of devices.
In large networks, structured addressing (routing, in the narrow sense)
outperforms unstructured addressing (bridging).
16. ROUTER
BBDNIIT
ROUTER AND THE NETWORK LAYER
The main purpose of a router is to connect multiple networks and forward
packets destined either for its own networks or other networks. A router is
considered a Layer 3 device because its primary forwarding decision is based
on the information in the Layer 3 IP packet, specifically the destination IP
address. This process is k
When a router receives a packet, it examines its destination IP address. If the
destination IP address does not belong to any of the router's directly
connected networks, the router must forward this packet to another router. In
the figure, R1 examines the destination IP address of the packet. After
searching the routing table, R1 forwards the packet onto R2. When R2
receives the packet, it also examines the packet's destination IP address.
After searching its routing table, R2 forwards the
connected Ethernet network to PC2.
When each router receives a packet, it searches its routing table to find the
best match between the destination IP address of the packet and one of the
network addresses in the routing table. On
encapsulated in the layer 2 data link frame for that outgoing interface. The
type of data link encapsulation depends on the type of interf
Ethernet or HDLC.
ROUTER AND THE NETWORK LAYER
The main purpose of a router is to connect multiple networks and forward
packets destined either for its own networks or other networks. A router is
considered a Layer 3 device because its primary forwarding decision is based
on the information in the Layer 3 IP packet, specifically the destination IP
s process is known as routing.
When a router receives a packet, it examines its destination IP address. If the
destination IP address does not belong to any of the router's directly
connected networks, the router must forward this packet to another router. In
, R1 examines the destination IP address of the packet. After
searching the routing table, R1 forwards the packet onto R2. When R2
receives the packet, it also examines the packet's destination IP address.
After searching its routing table, R2 forwards the packet out its directly
connected Ethernet network to PC2.
When each router receives a packet, it searches its routing table to find the
best match between the destination IP address of the packet and one of the
network addresses in the routing table. Once a match is found, the packet is
encapsulated in the layer 2 data link frame for that outgoing interface. The
type of data link encapsulation depends on the type of interf
Page 16
ROUTER AND THE NETWORK LAYER
The main purpose of a router is to connect multiple networks and forward
packets destined either for its own networks or other networks. A router is
considered a Layer 3 device because its primary forwarding decision is based
on the information in the Layer 3 IP packet, specifically the destination IP
When a router receives a packet, it examines its destination IP address. If the
destination IP address does not belong to any of the router's directly
connected networks, the router must forward this packet to another router. In
, R1 examines the destination IP address of the packet. After
searching the routing table, R1 forwards the packet onto R2. When R2
receives the packet, it also examines the packet's destination IP address.
packet out its directly
connected Ethernet network to PC2.
When each router receives a packet, it searches its routing table to find the
best match between the destination IP address of the packet and one of the
ce a match is found, the packet is
encapsulated in the layer 2 data link frame for that outgoing interface. The
type of data link encapsulation depends on the type of interface, such as
17. ROUTER
BBDNIIT Page 17
Eventually the packet reaches a router that is part of a network that matches
the destination IP address of the packet. In this example, router R2 receives
the packet from R1. R2 forwards the packet out its Ethernet interface, which
belongs to the same network as the destination device, PC2.
This sequence of events is explained in more detail later in this chapter.
Routers Operate at Layers 1, 2, and 3
A router makes its primary forwarding decision at Layer 3, but as we saw
earlier, it participates in Layer 1 and Layer 2 processes as well. After a router
has examined the destination IP address of a packet and consulted its routing
table to make its forwarding decision, it can forward that packet out the
appropriate interface toward its destination. The router encapsulates the
Layer 3 IP packet into the data portion of a Layer 2 data link frame
appropriate for the exit interface. The type of frame can be an Ethernet,
HDLC, or some other Layer 2 encapsulation - whatever encapsulation is used
on that particular interface. The Layer 2 frame is encoded into the Layer 1
physical signals that are used to represent bits over the physical link.
To understand this process better, refer to the figure. Notice that PC1
operates at all seven layers, encapsulating the data and sending the frame
out as a stream of encoded bits to R1, its default gateway.
R1 receives the stream of encoded bits on its interface. The bits are decoded
and passed up to Layer 2, where R1 decapsulates the frame. The router
examines the destination address of the data link frame to determine if it
matches the receiving interface, including a broadcast or multicast address. If
there is a match with the data portion of the frame, the IP packet is passed up
to Layer 3, where R1 makes its routing decision. R1 then re-encapsulates the
packet into a new Layer 2 data link frame and forwards it out the outbound
interface as a stream of encoded bits.
R2 receives the stream of bits, and the process repeats itself. R2
decapsulates the frame and passes the data portion of the frame, the IP
packet, to Layer 3 where R2 makes its routing decision.
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TYPES OF ROUTER
BROADBAND ROUTER
A broadband router combines the features of a traditional network switch,
anetwork firewall, and a DHCP server. Broadband routers are designed for
convenience in setting up home networks, particularly for homes with high-
speed Internet service. Besides easier sharing of a home Internet connection,
broadband routers also enable sharing of files, printers and other resources
among home computers.
A broadband router utilizes the Ethernet standard for wired connections.
Traditional broadband routers required Ethernet cables be run between the
router, the broadband modem, and each computer on the home network.
Newer broadband routers also incorporate wireless networking capability
utilizing the Wi-Fistandards.
Several manufacturers offer broadband router products to consumers.
Features that differentiate broadband router products
19. ROUTER
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WIRELESS ROUTER
A wireless router is a device that performs the functions of a router but also
includes the functions of a wireless access point. It is commonly used to
provide access to the Internet[note 1]
or a computer network. It does not require
a wired link, as the connection is made wirelessly, via radio waves. It can
function in a wired LAN (local area network), in a wireless-only LAN (WLAN),
or in a mixed wired/wireless network, depending on the manufacturer and
model.
Most current wireless routers have the following characteristics:
• One or multiple NICs supporting Fast Ethernet or Gigabit
Ethernet integrated into the main SoC
• One or multiple WNICs supporting a part of the IEEE 802.11-standard
family also integrated into the main SoC or as separate chips on
the Printed circuit board. It also can be a distinct card connected over
a MiniPCI or MiniPCIe interface.
20. ROUTER
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• So far the PHY-Chips for the WNICs are generally distinct chips on the
PCB. Dependent on the mode the WNIC supports, i.e. 1T1R, 2T2R or
3T3R, one WNIC have up to 3 PHY-Chips connected to it. Each PHY-Chip
is connected to a Hirose U.FL-connector on the PCB. A so-called pigtail
cable connects the Hirose U.FL either to a RF connector, in which case
the antenna can be changed or directly to the antenna, in which case it is
integrated into the casing. Common are single-band (i.e. only for 2.4 GHz
or only for 5 GHz) and dual-band (i.e. for 2.4 and 5 GHz) antennas.
• Often an Ethernet Switch supporting Gigabit Ethernet or Fast Ethernet,
with support for IEEE 802.1Q, integrated into the main SoC
(MediaTekSoCs) or as separate Chip on the PCB.
• Some wireless routers come with either xDSL
modem, DOCSIS modem, LTE modem, or fiber optic modem integrated.
• IEEE 802.11n compliant or ready.
• Some dual-band wireless routers operate the 2.4 GHz and 5 GHz bands
simultaneously.
• Some high end dual-band wireless routers have data transfer rates of at
most 300 Mbit/s (For 2.4 GHz band) and 450 Mbit/s (For 5 GHz band).
• Some wireless routers have 1 or 2 USB port(s). For wireless routers
having 1 USB port, it is designated for either printer or desktop/mobile
external hard disk drive. For wireless routers having 2 USB ports, one is
designated for the printer and the other one is designated for either
desktop or mobile external hard disk drive.
• Some wireless routers have a USB port specifically designed for
connecting 3G mobile broadband modem aside from connecting the
wireless router to a xDSL modem.
21. ROUTER
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EDGE ROUTER
An edge router is a specialized router residing at the edge or boundary of a
network. This router ensures
networks, a wide area network or the Internet. An edge router uses an
External Border Gateway Protocol, which is used extensively over the Internet
to provide connectivity with remote networks.
Instead of providing communication with an internal network, which the core
router already manages, an edge router may provide communication with
different networks and autonomous systems.
This term is also sometimes known as an access router or core router.
Edge routers use External BGP Protocol for data transmission because they
are intermediary devices between two different networks and operate at the
external or border layer of the network. There are several types of edge
routers, including edge routers placed
an essential device for connecting the host network with the Internet.
Whenever a node sends data on a network unmonitored by the host
administrator, the data packet is sent to the last router on the authorized
network, which is the edge router.
CORE ROUTER
An edge router is a specialized router residing at the edge or boundary of a
network. This router ensures the connectivity of its network with external
networks, a wide area network or the Internet. An edge router uses an
External Border Gateway Protocol, which is used extensively over the Internet
ectivity with remote networks.
ding communication with an internal network, which the core
router already manages, an edge router may provide communication with
different networks and autonomous systems.
This term is also sometimes known as an access router or core router.
routers use External BGP Protocol for data transmission because they
are intermediary devices between two different networks and operate at the
external or border layer of the network. There are several types of edge
routers, including edge routers placed at the outer boundary of the network as
an essential device for connecting the host network with the Internet.
Whenever a node sends data on a network unmonitored by the host
administrator, the data packet is sent to the last router on the authorized
rk, which is the edge router.
Page 21
An edge router is a specialized router residing at the edge or boundary of a
the connectivity of its network with external
networks, a wide area network or the Internet. An edge router uses an
External Border Gateway Protocol, which is used extensively over the Internet
ding communication with an internal network, which the core
router already manages, an edge router may provide communication with
different networks and autonomous systems.
This term is also sometimes known as an access router or core router.
routers use External BGP Protocol for data transmission because they
are intermediary devices between two different networks and operate at the
external or border layer of the network. There are several types of edge
at the outer boundary of the network as
an essential device for connecting the host network with the Internet.
Whenever a node sends data on a network unmonitored by the host
administrator, the data packet is sent to the last router on the authorized
22. ROUTER
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A core router is a router designed to operate in the Internet backbone, or core.
To fulfill this role, a router must be able to support multiple
telecommunications interfaces of the highest speed in use in the core Internet
and must be able to forward IP packets at full speed on all of them. It must
also support the routing protocols being used in the core. A core router is
distinct from an edge router: edge routers sit at the edge of a backbone
network and connect to core routers
.
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FUNCTION OF A ROUTER
A router (including a wireless router) is a specialized networking device
connected to two or more networks running software that allows the router to
move data from one network to another. Router functions in an Internet
protocol based network operate at the network layer (OSI Model's layer 3).
The primary function of a router is to connect networks together and keep
certain kinds of broadcast traffic under control they are several companies
that make routers cisco,Linksys , Juniper, Netgear, NORTEL, Redback,
Lucent
FUNCTIONS OF A ROUTER (identify and describe)
1. Restrict broadcasts to the LAN
2. Act as the default gateway.
3. Perform Protocol Translation (Wired Ethernet to Wireless/WiFi, or Ethernet
to CATV)
4. Move (route) data between networks
5. Learn and advertise loop free paths
Restrict Broadcasts to the LAN
Networks (especially Ethernet networks) use broadcast communication at
the physical, datalink and network layer. Network layer broadcasts are
transmissions sent to all hosts using the network layer protocol
(usually Internet Protocol [IP] or IPX). Network broadcast communication is
used to communicate certain kinds of information that makes
the network function (ARP, RARP, DHCP, IPX-SAP broadcasts etc.). Since
several devices could attempt to transmit simultaneously and cause collisions,
it is preferable to separate large sets of hosts into different broadcast domains
using a switch, or router.
As the number of hosts on the network increases, the amount
of broadcast traffic increases. If enough broadcast traffic is present on
24. ROUTER
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the network, then ordinary communication across the network becomes
difficult.
To reduce broadcasts, a network administrator can break up a network with a
large number of hosts into two smaller networks. Broadcasts are then
restricted to each network, and the router performs as the 'default gateway' to
reach the hosts on the other networks.
Act as the Default Gateway
Especially in today's networks, people want to use their computer to connect
to the Internet. When your computer wants to talk to a computer on
another network, it does so by sending your data to the default gateway. The
default gateway is the local router connected to the same network your
computer is connected to. The router serving as the default gateway receives
your data, looks for the remote address of that far-off computer and makes a
routing decision. Based on that routing decision, it forwards your data out a
different interface that is closer to that remote computer. There could be
several routers between you and the remote computer, so several routers will
take part in handing off the packet, much like a fireman's bucket brigade.
Move (route) Data between Networks
Routers have the capability to move data from one network to another. This
allows two networks managed by different organizations to exchange data.
They create a network between them and exchange data between the routers
on that network. Because a router can accept traffic from any kind of network
it is attached to, and forward it to any other network, it can also allow networks
that could not normally communicate with each other to exchange data. In
technical terms, a token ring network and an ethernet network can
communicate over a serial network. Routers make all this possible.
A router can take in an Ethernet frame, strip the ethernet data off, and then
drop the IP data into a frame of another type such as SDH/SONET, PDH/T1,
ATM, FDDI. In this way a router can also perform 'protocol conversion',
provided it has the appropriate hardware and software to support such a
25. ROUTER
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function. The whole point, however, is to forward the data from the interface it
receives data on, to another interface that retransmits the received data onto
another interface serving another network.
Learn and Advertise Loop-Free Paths
Routers can only learn and advertise routes dynamically if they are using a
routing protocol such as RIP, OSPF, EIGRP, IS-IS or BGP. Otherwise, a
human has to configure the routes by hand, which is called static routing.
Routing moves data on a hop-by-hop basis, what is often called 'hot potato'
routing. If a set of routers ends up passing the data around in a circle, without
reaching the destination, it's calleda a 'routing loop'. Packets get handed off
around the loop until they die of old age: their 'Time To Live' expires. Time To
Live is a counter that is part of the IP datagram header. The Time To Live
value is decremented as it passes through each router and eventually it
reaches zero and is discarded.
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ROUTER COMPONENT
The components of a modern router differ very slightly from the PC
architecture. The most obvious difference internally is that there is no hard
disk. The router has non-volatile Flash memory to hold the operating system
whilst power is off. It also has another type of non-volatile memory known as
NVRAM to hold files containing the setup details for the router once it has
been configured. In common with the PC, the router has RAM and ROM, a
motherboard and ports through which it can be accessed.
Externally, the router has no monitor nor keyboard attached during normal
operation. To access the router, it is necessary to use a PC and the
appropriate program to interface with the router. When a router is first
purchased, it is necessary to use a PC running a terminal emulator such as
hyperterminal to set up the initial configuration, however once the router is in
operation in a live network, it is possible to access the router either by
TELNET or by using a modem to make a direct connection via POTS.
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ROUTER MOTHERBOARD
ROUTER CPU
50 MHz CPUs are generally used for small offices & homes.For more
powerful purposes, processors from Motorola, Silicon Graphics, etc. are used.
RAM
It is also called dynamic RAM (DRAM), has the following characteristics and
functions:
1. Stores routing tables
2. Holds ARP cache
3. Holds fast-switching cache
4. Performs packet buffering (shared RAM)
5. Provides temporary memory for the configuration file of the router while
the router is powered on
6. Loses content when router is powered down or restarted
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NVRAM
It has the following characteristics and functions:
1. Provides storage for the startup configuration file
2. Retains content when router is powered down or restarted
Flash memory
It has the following characteristics and functions:
1. Holds the operating system image (IOS)
2. Allows software to be updated without removing and replacing chips on
the processor
3. Retains content when router is powered down or restarted.
4. Can store multiple versions of IOS software
5. Is a type of electronically erasable, programmable ROM (EEPROM)
Read-only memory (ROM)
It has the following characteristics and functions:
1. Maintains instructions for power-on self test (POST) diagnostics
2. Stores bootstrap program and basic operating system software
3. Requires replacing pluggable chips on the motherboard for software
upgrades
Interfaces have the following characteristics and functions:
• Connect router to network for frame entry and exit
• Can be on the motherboard or on a separate module
29. ROUTER
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APPLICATIONS OF ROUTER
When multiple routers are used in interconnected networks, the routers
exchange information about destination addresses using a dynamic routing
protocol. Each router builds up a table listing the preferred routes between
any two systems on the interconnected networks. A router has interfaces for
different physical types of network connections, (such as copper cables, fiber
optic, or wireless transmission). It also contains firmware for different
networking Communications protocol standards. Each network interface uses
this specialized computer software to enable data packets to be forwarded
from one protocol transmission system to another.
Routers may also be used to connect two or more logical groups of computer
devices known as subnets, each with a different sub-network address. The
subnets addresses recorded in the router do not necessarily map directly to
the physical interface connections.
A router has two stages of operation called planes.
• Control plane: A router records a routing table listing what route should be
used to forward a data packet, and through which physical interface
connection. It does this using internal pre-configured directives, called
static routes, or by learning routes using a dynamic routing protocol. Static
and dynamic routes are stored in the Routing Information Base (RIB). The
control-plane logic then strips the RIB from non essential directives and
builds a Forwarding Information Base (FIB) to be used by the forwarding-
plane.
30. ROUTER
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• Forwarding plane: The router forwards data packets between incoming
and outgoing interface connections. It routes it to the correct network type
using information that the packet header contains. It uses data recorded in
the routing table control plane.
Routers may provide connectivity within enterprises, between enterprises and
the Internet, and between internet service providers (ISPs) networks. The
largest routers (such as the Cisco CRS-1 or Juniper T1600) interconnect the
various ISPs, or may be used in large enterprise networks.[4]
Smaller routers
usually provide connectivity for typical home and office networks. Other
networking solutions may be provided by a backbone Wireless Distribution
System (WDS), which avoids the costs of introducing networking cables into
buildings.
All sizes of routers may be found inside enterprises.[5]
The most powerful
routers are usually found in ISPs, academic and research facilities. Large
businesses may also need more powerful routers to cope with ever increasing
demands of intranet data traffic. A three-layer model is in common use, not all
of which need be present in smaller networks.
ACCESS
Access routers, including 'small office/home office' (SOHO) models, are
located at customer sites such as branch offices that do not need hierarchical
routing of their own. Typically, they are optimized for low cost. Some SOHO
routers are capable of running alternative free Linux-based firmwares like
Tomato, OpenWrt or DD-WRT.
DISTRIBUTION
Distribution routers aggregate traffic from multiple access routers, either at the
same site, or to collect the data streams from multiple sites to a major
enterprise location. Distribution routers are often responsible for enforcing
quality of service across a WAN, so they may have considerable memory
installed, multiple WAN interface connections, and substantial onboard data
31. ROUTER
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processing routines. They may also provide connectivity to groups of file
servers or other external networks.
SECURITY
External networks must be carefully considered as part of the overall security
strategy. Separate from the router may be a firewall or VPN handling device,
or the router may include these and other security functions. Many companies
produced security-oriented routers, including Cisco Systems' PIX and
ASA5500 series, Juniper's Netscreen, Watchguard's Firebox, Barracuda's
variety of mail-oriented devices, and many others.
CORE
In enterprises, a core router may provide a "collapsed backbone"
interconnecting the distribution tier routers from multiple buildings of a
campus, or large enterprise locations. They tend to be optimized for high
bandwidth, but lack some of the features of Edge Routers.[8]
INTERNET CONNECTIVITY AND INTERNAL USE
Routers intended for ISP and major enterprise connectivity usually exchange
routing information using the Border Gateway Protocol (BGP). RFC
4098 standard defines the types of BGP-protocol routers according to the
routers' functions:
• Edge router: Also called a Provider Edge router, is placed at the edge of
an ISP network. The router uses External BGP to EBGP protocol routers
in other ISPs, or a large enterpriseAutonomous System.
• Subscriber edge router: Also called a Customer Edge router, is located at
the edge of the subscriber's network, it also uses EBGP protocol to its
provider's Autonomous System. It is typically used in an (enterprise)
organization.
32. ROUTER
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• Inter-provider border router: Interconnecting ISPs, is a BGP-protocol
router that maintains BGP sessions with other BGP protocol routers in ISP
Autonomous Systems.
• Core router: A core router resides within an Autonomous System as a
back bone to carry traffic between edge routers.[10]
• Within an ISP: In the ISPs Autonomous System, a router uses internal
BGP protocol to communicate with other ISP edge routers,
other intranet core routers, or the ISPs intranet provider border routers.
• "Internet backbone:" The Internet no longer has a clearly identifiable
backbone, unlike its predecessor networks. See default-free zone (DFZ).
The major ISPs system routers make up what could be considered to be
the current Internet backbone core.[11]
ISPs operate all four types of the
BGP-protocol routers described here. An ISP "core" router is used to
interconnect its edge and border routers. Core routers may also have
specialized functions in virtual private networks based on a combination of
BGP and Multi-Protocol Label Switching protocols.[12]
• Port forwarding: Routers are also used for port forwarding between private
internet connected servers.[5]
• Voice/Data/Fax/Video Processing Routers: Commonly referred to
as access servers or gateways, these devices are used to route and
process voice, data, video, and fax traffic on the internet. Since 2005,
most long-distance phone calls have been processed as IP traffic (VOIP)
through a voice gateway. Voice traffic that the traditional cable networks
uses. Use of access server type routers expanded with the advent of the
internet, first with dial-up access, and another resurgence with voice
phone service.
33. ROUTER
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ADVANTAGE OF ROUTER
In addition to packet forwarding, a router provides other services as well. To
meet the demands on today's networks, routers are also used :
1. To ensure steady, reliance availability of network connectivity. Routers use
alternative parts in the case the primary part fails to the delivery of
packets.
2. To provide integrated services of data, video, and voice over wired and
wireless networks.
For security, router helps in mitigating the impact of worms, viruses, and other
attacks on the network by permitting or denying the forwarding of packets.
Easily Shared Internet
One of the biggest reasons for using a router is to connect multiple users to
the Internet. Connecting to the Internet requires a publicly-unique IP address.
As such, Internet providers typically only offer a single IP address or charge
fees for large amounts of publicly routable addresses. The solution is to add a
router with network address translation enabled. Connecting to the Internet
through a router with NAT allows the router to use the single public IP address
and a series of UDP ports to share the connection. Without NAT, connecting a
large organization’s computers to the Internet becomes virtually impossible.
Security and Adaptability
Connecting an Internet modem directly to a PC exposes that PC to a host of
security issues. Furthermore, expanding a direct-connection network
becomes complicated without the addition of switches or a router and
communicating between the individual PCs becomes difficult. Using a router
as an intermediary between the “outside” network of the Internet and the
“inside” network of your organization provides a scalable environment that is
also, to a degree, easier to secure.
34. ROUTER
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DISADVANTAGE OF ROUTER
1. Router is more expensive than Hub, Bridge & Switch.
2. Router only waork with routable protocol.
3. Routing updates consume bandwidth.
4. Increase latency due to greater degree of packet filtering.
Complicated Setup
The aforementioned router requires NAT to be set up. In addition, each
computer must be assigned a private IP address that is typically organized by
a DHCP server. This is required for the simplest connections. Connecting to
additional IP-based networks adds additional complication in the form of
routing tables -- a table that describes the best route for reaching a desired
network. If IP telephony or video services are to be running on the IP network,
you’ll also need to consider quality of service configurations. QoS helps
prioritize one type of traffic, such as voice, over others when bandwidth is
limited. As additional services are added, more configuration becomes
required of the router.
Data Overhead
Unlike a point-to-point “layer 2” link, routers add additional IP-based headers.
These headers include information such as source and destination addresses,
UDP information and checksums. These headers are attached to every
payload of data. Large pieces of data are typically broken into thousands of
smaller headers, making this header data consume a percentage of the total
available bandwidth. Additionally, the routers communicate updates on the
network in order to maintain routing tables. When possible, eliminating the
routed network environment will offer a nominal speed gain.
35. ROUTER
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CONCLUSION
Thus a router is an electronic device that interconnects two or more computer
networks. It works at Layer 3, Network Layer in an intelligent manner and can
connect different network segments, whether they are in the same building or
even on the opposite side of the globe
It works in LAN, WAN environments and allows access to resources by
selecting the best path. It can interconnect different networks. A Router
changes packet size and format to match the requirements of the destination
network .
Routing is the process of selecting best paths in a network. In the past, the
term routing was also used to mean forwarding network traffic among
network. Routing is performed for many kinds of networks, including
the telephone network (circuit switching), electronic data networks (such as
the Internet), andtransportation networks
We have also studied about the various components of Router such as
motherboard,CPU,RAM ,NVRAM,ROM etc.Alongwith this certain applications
of router have also been studied
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BIBILIOGRAPHY
• The Router Book: A Complete Guide to the Router and Its
Accessories Paperback by Pat Warner (Author)
• Router Basics (Basics Series) Paperback by Patrick Spielman (Author)
• http://en.wikipedia.org/wiki/Router_(computing)
• http://ecomputernotes.com/computernetworkingnotes/communication-
networks/what-is-routers-explain-types-of-routers
• http://www.orbit-computer-solutions.com/Types-of-Router.php
• http://blogs.cisco.com/smallbusiness/understanding-the-different-types-of-
wireless-routers/
• http://compnetworking.about.com/od/homenetworking/a/routernetworks.ht
m
• https://www.google.co.in/search?q=what+is+router+motherboard&oq=wha
t+is+router&aqs=chrome.0.69i59j69i57j0l2j69i60l2.10055j0j8&sourceid=ch
rome&espv=210&es_sm=93&ie=UTF-8
• http://www.techpowerup.com/forums/threads/what-is-the-point-of-two-
ethernet-ports-on-my-motherboard.168960/