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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter22 Configuring IP Unicast Routing Configuring RIP
Configuring RIP
The Routing Information Protocol (RIP) is an interior gateway pr otoc ol (I GP) cre ate d fo r us e in sma ll,
homogeneous networks. It is a distance-vector routing prot ocol th at use s b roadc as t Us er D at ag ram
Protocol (UDP) data packets to exchange routing information. The protocol is docume nted in RFC 1058.
You can find detailed information about RIP in IP Routing Fundamentals, published by Cisco Press.
Using RIP, the switch sends routing information updates (advertisements) every 30 seconds. If a router
does not receive an update from another router for 180 secon ds o r mor e, it ma rks the rout es serv ed by
that router as unusable. If there is still no update after 240 seconds, the router removes all routing table
entries for the non-updating router.
RIP uses hop counts to rate the value of different routes. The hop count is the numbe r of routers that can
be traversed in a route. A directly connected network has a hop count o f zero; a network with a hop count
of 16 is unreachable. This small range (0 to 15) makes RIP unsuita ble f or l arge netw orks.
If the router has a default network path, RIP advertises a rout e that links the router to the pseudonetwork
0.0.0.0. The 0.0.0.0 network does not exist; it is treated by RIP as a network to implement the default
routing feature. The switch advertises the default network if a def ault was learned by RIP or if the router
has a gateway of last resort and RIP is configured with a default metric. RIP sends updates to the
interfaces in specified networks. If an interface’s network is not specified, it is not advertised in any
RIP update.
Table22-5 show s the de faul t RI P conf igur ation .
Table22-5 Default RIP Configuration
Feature Default Setting
Auto summary Enabled.
Default-information originate Disabled.
Default metric Built-in; automatic metric translations.
IP RIP authentication key-chain No authentication.
Authentication mode: clear text.
IP RIP receive version According to the version router configuration command.
IP RIP send version According to the version router configuration command.
IP RIP triggered According to the version router configuration command.
IP split horizon Varies with media.
Neighbor None defined.
Network None specified.
Offset list Disabled.
Output delay 0 milliseconds.
Timers basi c •Update: 30 seconds.
•Invalid: 180 seconds.
•Hold-down: 180 seconds.
•Flush: 240 seconds.