RIP: UDP 520; update = 30s, invalidation = 6×30, holddown = 6×30, flush = invalidation +120s (Cisco uses +60s)
router rip
timers basic <update> <invalid> <holddown> < flush>
Changing the timer on any one router affects every neighbor it talks to => affects RIP domain
Triggered update: Only over serial links, only when changes occur. Timer 1-5s. Configured at both ends. (RIP timer expiry is observed in debugs)
debug ip rip trigger
interface se1/0
ip rip triggered.
Max message size =512 bytes.
Command: 1= Request, 2= response, AFID = 2 for IP. (When a full table is requested, AFID=0, IP=0.0.0.0 & metric=16)
Classful Routing: If the n/w does not match the subnet of it’s i/f, RIP will treat is as a major n/w.
Passive if: router rip; passive interface se1/0 – > no updates are sent.
Neighbor: Default updates are b/c. router rip, neighbor <ip> will force unicast
Secondary IP address: To connect two discontigous n/ws, configure a secondary IP address with same mask and same classful n/w (for eg. 10.75.3.1 255.255.252.0 to connect 10.55.3.1 255.255.252.0)
Offset-List: Used to influence RIP metrics.
access-list 1 permit 10.33.0.0 0.0.0.0 (mask matches the n/w exactly)
router rip
offset-list 1 in 3 se 1/0 (add a metric of 3 to traffic matching ACL 1, incoming on se1/0)
If no i/f is specified, any traffic matching the acl on any i/f is affected.
If no ACL, all traffic through that i/f is affected
Troubleshooting: If there is a slow – fast neighbor combination and the slow router cant keep up with the RIP updates; on the faster router:
router rip
output-delay <8-50ms>
