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Implementing RIP on Cisco IOS XR Software
Information About Implementing RIP on Cisco IOS XR Software
RC-336
Cisco IOS XR Routing Configuration Guide
OL-14356-01
Route Redistribution for RIP
Redistribution is a feature that allows different routing domains, to exchange routing information.
Networking devices that route between different routing domains are called boundary routers, and it is
these devices that inject the routes from one routing protocol into another. Routers within a routing
domain only have knowledge of routes internal to the domain unless route redistribution is implemented
on the boundary routers.
When running RIP in your routing domain, you might find it necessary to use multiple routing protocols
within your internetwork and redistribute routes between them. Some common reasons are:
• To advertise routes from other protocols into RIP, such as static, connected, OSPF and BGP.
• To migrate from RIP to a new Interior Gateway Protocol (IGP) such as EIGRP.
• To retain routing protocol on some routers to support host systems, but upgrade routers for other
department groups.
• To communicate among a mixed-router vendor environment. Basically, you might use a protocol
specific to Cisco in one portion of your network and use RIP to communicate with devices other than
Cisco devices.
Further, route redistribution gives a company the ability to run different routing protocols in work groups
or areas in which each is particularly effective. By not restricting customers to using only a single routing
protocol, Cisco IOS XR route redistribution is a powerful feature that minimizes cost, while maximizing
technical advantage through diversity.
When it comes to implementing route redistribution in your internetwork, it can be very simple or very
complex. An example of a simple one-way redistribution is to log into a router on which RIP is enabled
and use the redistribute static command to advertise only the static connections to the backbone
network to pass through the RIP network. For complex cases in which you must consider routing loops,
incompatible routing information, and inconsistent convergence time, you must determine why these
problems occur by examining how Cisco routers select the best path when more than one routing
protocol is running administrative cost.
Default Administrative Distances for RIP
Administrative distance is used as a measure of the trustworthiness of the source of the IP routing
information. When a dynamic routing protocol such as RIP is configured, and you want to use the
redistribution feature to exchange routing information, it is important to know the default administrative
distances for other route sources so that you can set the appropriate distance weight. See Table 1 for a
list of the default administrative distances.
Table 1 Default Administrative Distances of Routing Protocols
Routing Protocols Administrative Distance Value
Connected interface 0
Static route out an interface 0
Static route to next hop 1
EIGRP Summary Route 5
External BGP 20
Internal EIGRP 90
OSPF 110