Information About Rip - Cisco Catalyst 9500 series Configuration Manual

Information About RIP

• EIGRP
• BGP
• Unicast Reverse Path Forwarding
• Protocol-Independent Features (optional)
Information About RIP
The Routing Information Protocol (RIP) is an interior gateway protocol (IGP) created for use in small,
homogeneous networks. It is a distance-vector routing protocol that uses broadcast User Datagram Protocol
(UDP) data packets to exchange routing information. The protocol is documented in RFC 1058. You can find
detailed information about RIP in IP Routing Fundamentals, published by Cisco Press.
RIP is supported in the Network Essentials feature set.
Note
Using RIP, the Device sends routing information updates (advertisements) every 30 seconds. If a router does
not receive an update from another router for 180 seconds or more, it marks the routes served 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 number of routers that can be
traversed in a route. A directly connected network has a hop count of zero; a network with a hop count of 16
is unreachable. This small range (0 to 15) makes RIP unsuitable for large networks.
If the router has a default network path, RIP advertises a route 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 Device advertises the default network if a default 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.
Summary Addresses and Split Horizon
Routers connected to broadcast-type IP networks and using distance-vector routing protocols normally use
the split-horizon mechanism to reduce the possibility of routing loops. Split horizon blocks information about
routes from being advertised by a router on any interface from which that information originated. This feature
usually optimizes communication among multiple routers, especially when links are broken.
Routing Configuration Guide, Cisco IOS XE Everest 16.6.x (Catalyst 9500 Switches)
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Configuring IP Unicast Routing