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A routing protocol specifies how routers communicate with each other, distributing information that enables them to select routes between any two nodes on a computer network. Routers perform the "traffic directing" functions on the Internet; data packets are forwarded through the networks of the internet from router to router until they reach their destination computer. Routing algorithms determine the specific choice of route. Each router has a prior knowledge only of networks attached to it directly. A routing protocol shares this information first among immediate neighbors, and then throughout the network. This way, routers gain knowledge of the topology of the network. The ability of routing protocols to dynamically adjust to changing conditions such as disabled data lines and computers and route data around obstructions is what gives the Internet its survivability and reliability.

The specific characteristics of routing protocols include the manner in which they avoid routing loops, the manner in which they select preferred routes, using information about hop costs, the time they require to reach routing convergence, their scalability, and other factors.

Many routing protocols are defined in documents called RFCs.[1][2][3][4]

TypesEdit

Although there are many types of routing protocols, three major classes are in widespread use on IP networks:

OSI layer designationEdit

Routing protocols, according to the OSI routing framework, are layer management protocols for the network layer, regardless of their transport mechanism:

Interior gateway protocolsEdit

Exterior gateway protocolsEdit

Exterior gateway protocols exchange routing information between autonomous systems. Examples include:

Routing softwareEdit

Many software implementations exist for most of the common routing protocols. Examples of open-source applications are Bird Internet routing daemon, Quagga, GNU Zebra, OpenBGPD, OpenOSPFD, and XORP.

Routed protocolsEdit

Some network certification courses distinguish between routing protocols and routed protocols. A routed protocol is used to deliver application traffic. It provides appropriate addressing information in its internet layer or network layer to allow a packet to be forwarded from one network to another. Examples of routed protocols are the Internet Protocol (IP) and Internetwork Packet Exchange (IPX).

See alsoEdit

NotesEdit

  1. ^ Cisco no longer supports the proprietary IGRP protocol. The EIGRP implementation accepts IGRP configuration commands, but the internals of IGRP and EIGRP are different.

ReferencesEdit

Further readingEdit