Information Technology Reference
In-Depth Information
Core Router Configuration for R3 (Continued)
Example A-8
neighbor 10.1.1.4 remote-as 65100
neighbor 10.1.1.4 update-source Loopback0
neighbor 10.1.1.5 remote-as 65100
neighbor 10.1.1.5 update-source Loopback0
neighbor 172.16.1.5 remote-as 65101
no auto-summary
!
address-family nsap
neighbor 10.1.1.2 activate
neighbor 10.1.1.4 activate
neighbor 10.1.1.5 activate
neighbor 172.16.1.5 activate
neighbor 172.16.1.5 default-originate
neighbor 172.16.1.5 prefix-list DEFAULT_OUT out
network 47.3333.3333.3333.3333.00
no synchronization
exit-address-family
!
clns filter-set DEFAULT_OUT is applied to the BGP peering session to prevent any
prefixes from being advertised from the core to the aggregation routing domains except the
default.
The core network has IS-IS enabled in Integrated mode, which means that it is used for
both CLNS and IP routing, unlike in the aggregation routing domains, where IS-IS was in
CLNS-only mode. The reason for adding IP support in the core network is to provide IP
reachability for the BGP peering sessions.
The BGP NSAP address family configuration activates all the iBGP neighbors in the core
and the eBGP neighbor to R1. The default prefix is originated to R1 using the neighbor
172.16.1.5 default-originate command. All other NSAPs are blocked with the prefix list
DEFAULT_OUT, which is defined in Example A-8 using the clns filter-set command.
CLNS Support Caveats
BGP support for CLNS prefix information was first included in Cisco IOS software Release
12.2(8)T. This feature is available only in the Service Provider and Telco feature sets. The
following BGP features and commands are not supported for CLNS prefix information:
BGP confederations
BGP extended communities
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