Configuration Examples for Implementing Routing Policy
This section provides the following configuration examples:
Routing Policy Definition: Example
In the following example, a BGP route policy named sample1 is defined using the
route-policy name
command.
The policy compares the network layer reachability information (NLRI) to the elements in the prefix set test.
If it evaluates to true, the policy performs the operations in the
then
clause. If it evaluates to false, the policy
performs the operations in the
else
clause, that is, sets the MED value to 200 and adds the community 2:100
to the route. The final steps of the example commit the configuration to the router, exit configuration mode,
and display the contents of route policy sample1.
configure
route-policy sample1
if destination in test then
drop
else
set med 200
set community (2:100) additive
endif
end-policy
end
show config running route-policy sample1
Building configuration...
route-policy sample1
if destination in test then
drop
else
set med 200
set community (2:100) additive
endif
end-policy
Simple Inbound Policy: Example
The following policy discards any route whose network layer reachability information (NLRI) specifies a
prefix longer than /24, and any route whose NLRI specifies a destination in the address space reserved by
RFC 1918. For all remaining routes, it sets the MED and local preference, and adds a community to the list
in the route.
For routes whose community lists include any values in the range from 101:202 to 106:202 that have a 16-bit
tag portion containing the value 202, the policy prepends autonomous system number 2 twice, and adds the
community 2:666 to the list in the route. Of these routes, if the MED is either 666 or 225, then the policy sets
the origin of the route to incomplete, and otherwise sets the origin to IGP.
For routes whose community lists do not include any of the values in the range from 101:202 to 106:202, the
policy adds the community 2:999 to the list in the route.
prefix-set too-specific
0.0.0.0/0 ge 25 le 32
end-set
prefix-set rfc1918
Routing Configuration Guide for Cisco NCS 6000 Series Routers, IOS XR Release 6.4.x
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Implementing Routing Policy
Configuration Examples for Implementing Routing Policy