Cisco ASR 9000 Series Routing Configuration Guide

Note
•
Directly connected routes cannot be leaked using BGP VRF Dynamic Route Leaking from default
VRF to non-default VRF
•
A leaked route should not cover or override any routes in the destination VRF. For example consider
two connected routers R1 with destination VRF 'dest-vrf' and R2 with source VRF 'source-vrf'. The
source-vrf connected route CR-1 is leaked to dest-vrf. In this case, the route from dest-vrf is covered
or overridden by the leaked route CR-1 from the source-vrf.
The dynamic route leaking is enabled by:
•
Importing from default-VRF to non-default-VRF, using the import from default-vrf route-policy
route-policy-name [advertise-as-vpn] command in VRF address-family configuration mode.
If the advertise-as-vpn option is configured, the paths imported from the default-VRF to the
non-default-VRF are advertised to the PEs as well as to the CEs. If the advertise-as-vpn option is not
configured, the paths imported from the default-VRF to the non-default-VRF are not advertised to the
PE. However, the paths are still advertised to the CEs.
•
Importing from non-default-VRF to default VRF, using the export to default-vrf route-policy
route-policy-name command in VRF address-family configuration mode.
A route-policy is mandatory to filter the imported routes. This reduces the risk of unintended import of routes
between the Internet table and the VRF tables and the corresponding security issues.
There is no hard limit on the number of prefixes that can be imported. The import creates a new prefix in the
destination VRF, which increases the total number of prefixes and paths. However, each VRF importing
global routes adds workload equivalent to a neighbor receiving the global table. This is true even if the user
filters out all but a few prefixes. Hence, importing five to ten VRFs is ideal.
User Defined Martian Check
The Cisco IOS XR Software Release 5.1.0 allows disabling the Martian check for these IP address prefixes:
•
IPv4 address prefixes
◦
0.0.0.0/8
◦
127.0.0.0/8
◦
224.0.0.0/4
•
IPv6 address prefixes
◦
::
◦
::0002 - ::ffff
◦
::ffff:a.b.c.d
◦
fe80:xxxx
◦
ffxx:xxxx
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.3.x
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Implementing BGP
User Defined Martian Check

Cisco ASR 9000 Series Specifications

General

Brand	Cisco
Model	ASR 9000 Series
Category	Network Router
Language	English