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Chabot College. ELEC 99.05 Routed and Routing Protocols. Rout ed vs Rout ing Protocols. Rout ed Protocols. Used by end systems to communicate (a computer to another computer, etc.) Contain network-layer addresses of source and destination computers. Examples: TCP/IP IPX/SPX AppleTalk.
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Chabot College ELEC 99.05 Routed and Routing Protocols
Routed Protocols • Used by end systems to communicate (a computer to another computer, etc.) • Contain network-layer addresses of source and destination computers. • Examples: • TCP/IP • IPX/SPX • AppleTalk
Routing Protocols • Used by intermediate systems to communicate information about paths (router to router). • Contain routing information tables. • Examples: • RIP • IGRP • EIGRP • OSPF
2 Kinds of Routing Protocols • IGPs, Interior Gateway Protocols: used by routers inside an organization’s network • EGPs, Exterior Gateway Protocols: used between different organization’s routers
EGPs • We won’t study EGPs in this class. • There are two common EGPs: • EGP: Exterior Gateway Protocol • BGP: Border Gateway Protocol • BGP is newer and the most common.
IGPs • We study four IGPs in class: • RIP • IGRP • EIGRP • OSPF
RIP • RIP, or Routing Information Protocol • Very old protocol • Uses only one measure, or metric, to determine the desirability of a route: hop count • This type of metric is called distance-vector • Broadcasts routing information to neighbors every 30 seconds by default
Hop Count • Hop count is the number of routers a packet must past through to reach a destination. • RIP always chooses the path that has the fewest hops. (not always the fastest path) • RIP can only support routes with a hop count of less than 16. (16 is unreachable).
IGRP • IGRP, or Interior Gateway Routing Protocol • Cisco-proprietary • Uses multiple measures, or metrics, to determine best path, including bandwidth • Distance-vector metric • Preferred over RIP
OSPF • Open Shortest Path First • Non-proprietary • Uses multiple metrics • Updates directly to all routers, not just to neighbors • Link state metric
EIGRP • EIGRP, or Enhanced Interior Gateway Protocol • Cisco-Proprietary • Uses multiple metrics • Combines features of distance vector and link state routing protocols (a cross between IGRP and OSPF)
Static vs. Dynamic Routes • Static Route • Configured manually into the router. • Useful for stub networks • Dynamic Route • Learned automatically and adjusts for topology or traffic changes • Useful when multiple paths are available
Static vs. Dynamic Routes • Which are stub networks? • Which offer multiple paths? • Where would we use each type of route?
Convergence • Link State routing protocols converge faster than distance vector routing protocols.