Route Redistribution For Rip; Default Administrative Distances For Rip - Cisco ASR 9000 Series Routing Configuration Manual

Route Redistribution for RIP

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
• To communicate among a mixed-router vendor environment. Basically, you might use a protocol specific
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.
This table lists the Default Administrative Distances of Routing Protocols.
Table 6: Default Administrative Distances of Routing Protocols
Routing Protocols
Connected interface
Static route out an interface
Static route to next hop
EIGRP Summary Route
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department groups.
to Cisco in one portion of your network and use RIP to communicate with devices other than Cisco
devices.
Administrative Distance Value
0
0
1
5
Implementing RIP