Arouting protocol specifies howrouters communicate with each other to distribute information that enables them to select paths betweennodes on acomputer 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 thetopology of the network. The ability of routing protocols to dynamically adjust to changing conditions such as disabled connections and components and route data around obstructions is what gives the Internet itsfault tolerance andhigh availability.
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 reachrouting convergence, theirscalability, and other factors such as relay multiplexing and cloud access framework parameters. Certain additional characteristics such as multilayer interfacing may also be employed as a means of distributing uncompromised networking gateways to authorized ports.[1] This has the added benefit of preventing issues with routing protocol loops.[2]
Many routing protocols are defined intechnical standards documents calledRFCs.[3][4][5][6]
Although there are many types of routing protocols, three major classes are in widespread use onIP networks:
Routing protocols, according to the OSI routing framework, are layer management protocols for the network layer, regardless of their transport mechanism:
Interior gateway protocols (IGPs) exchange routing information within a singlerouting domain. Examples of IGPs include:
Exterior gateway protocols exchange routing information betweenautonomous systems. Examples include:
Many software implementations exist for most of the common routing protocols. Examples of open-source applications areBird Internet routing daemon,Quagga,GNU Zebra,OpenBGPD,OpenOSPFD, andXORP.
Some network certification courses distinguish between routing protocols androuted protocols. Arouted protocol is used to deliver application traffic. It provides appropriate addressing information in itsinternet layer ornetwork layer to allow a packet to be forwarded from one network to another. Examples of routed protocols are theInternet Protocol (IP) andInternetwork Packet Exchange (IPX).