R2511-HP MSR Router Series MPLS Configuration Guide(V5)

141
Ste
p
Command Remarks
16. Specify the preference value
for the routes received from
the peer/peer group.
peer { group-name | ip-address }
preferred-value value
Optional.
0 by default.
17. Make BGP updates to be sent
carry no private AS numbers.
peer { group-name | ip-address }
public-as-only
Optional.
By default, a BGP update carries
private AS numbers.
18. Apply a routing policy to a
peer or peer group.
peer { group-name | ip-address }
route-policy route-policy-name
{ export | import }
Optional.
By default, no routing policy is
applied to a peer or peer group.
For more information about BGP routing, see Layer 3—IP Routing Configuration Guide.
Configuring inter-AS VPN
If the MPLS backbone on which the VPN routes rely spans multiple ASs, you must configure inter-AS VPN.
Three inter-AS VPN solutions are available. You can choose them as required.
Before you configure an inter-AS VPN, complete the following tasks:
• Configure an IGP for the MPLS backbones in each AS to ensure IP connectivity of the backbones in
the AS.
• Configure basic MPLS for the MPLS backbones of each AS.
• Configure MPLS LDP for the MPLS backbones so that LDP LSPs can be established.
• Configure basic MPLS L3VPN for each AS.
When configuring basic MPLS L3VPN for each AS, specific configurations might be required on PEs or
ASBR PEs. This depends on the inter-AS VPN solution selected.
Configuring inter-AS option A
Inter-AS option A applies to scenarios where the number of VPNs and that of VPN routes on the PEs are
relatively small. It is simple to implement.
To configure inter-AS option A, complete the following tasks:
• Configure basic MPLS L3VPN on each AS.
• Configure each ASBR-PE, taking the peer ASBR-PE as its CE.
Configure VPN instances on PEs and ASBR PEs. The VPN instances on PEs are used to allow CEs to
access the network, and those on ASBR PEs are used to access the peer ASBR PEs. For more information,
see "Configuring basic MPLS L3VPN."
In the in
ter-AS option A solution, for the same VPN, the route targets configured on the PEs must match
those configured on the ASBR-PEs in the same AS to make sure VPN routes sent by the PEs (or ASBR-PEs)
can be received by the ASBR-PEs (or PEs). Route targets configured on the PEs in different ASs do not have
such requirements.
Configuring inter-AS option B
For inter-AS option B, two configuration methods are available: