Routing Protocols: Classification of Routing Protocols

Classification of Routing Protocols

Distance vectorExamples: Routing Information Protocol Version 1 (RIPv1), RIPv2, Interior Gateway Routing Protocol (IGRP) Features periodic transmission of entire routing tables to directly connected neighbors Mathematically compares routes using some measurement of distance Features hop-count limitation



Link StateExamples: Open Shortest Path First (OSPF), Intermediate System- to- Intermediate System (IS-IS). Sends local connection information to all nodes in the internetwork. Forms adjacencies with neighboring routers that speak the same protocol; sends local link information to these devices. Note that although this is flooding of information to all nodes, the router is sending only the portion of information that deals with

the state of its own links. Each router constructs its own complete “picture” or “map” of the network from all of the information received.



Hybrid
Example: Enhanced Interior Gateway Routing Protocol (EIGRP) Features properties of both distance vector and link-state routing protocols



Path vector protocolExample: Border Gateway Protocol (BGP). Path vector protocols are a subset of distance vector protocols; BGP uses “path vectors” or a list of all the autonomous systems a prefix has crossed to make metric decisions and to ensure a loop free environment. In addition to the autonomous system path list, an administrator can use many other factors to affect the forwarding or receipt of traffic using BGP.