RIP V2 CCNP S1(5), Chapter 4

Distance Vector Protocols Use split horizon, poison reverse, holddown, triggered updates, and route aging to prevent routing loops Use Bellman Ford algorithm (hop count) for best path – defined in RFC 1058 Can use load balancing to distribute traffice evenly among paths

RIPv2 Facts Distance Vector Protocol Classless – carries subnet mask in routing update Uses UDP port 520 Maximum hop count is 15 Hop count determines best path Maximum routes in routing update is 25 When route fails, an alternate route is determined from subsequent scheduled routing updates Optimal path is based on a configurable fixed cost metric

RIPV2 Continued An enhanced version of RipV1 Multicast updates sent on 224.0.0.9

RIPv1 and v2 Convergence When route fails, a flash update is sent and route entry is removed from table Called a triggered update with poison reverse Receiving router sends flash updates and puts affected route in holddown Originating router queries neighbor for alternative routes Originating router installs best alternative route it hears Routers in holddown ignore alternative route

RIPv2 Commands IP RIP send FA0/0 Debug IP RIP Will implement interface-level RIP compatability switches Debug IP RIP Will enable RIP routing transactions debugging IP RIP Authentication mode md5 Allows updates from neighbors No auto-summary Permits you to advertise discontiguous networks

RIPv2 Miscellaneous Passwords sent in clear text Can use passive interface command from router (config-router)# prompt to block interface from forwarding updates

RIP V1 and V2 Version 2 command RIP V2 will send and receive only V2 updates Default behavior for RIP is to send only V1 but listen for both V1 and V2 V2 adds route tag and subnet mask fields

Administrative Distance Connected Interface 0 Static Route 1 EIGRP Summary 5 BGP 20 EIGRP 90 IGRP 100 OSPF 110 RIP 120