Configuring inter-as vpn, Configuring inter-as option a, Configuring inter-as option b – H3C Technologies H3C S6800 Series Switches User Manual

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Step Command

Remarks

21.

Enable route reflection

between clients.

reflect between-clients

By default, route reflection
between clients is enabled on the
RR.

22.

Configure a cluster ID for the
route reflector.

reflector cluster-id { cluster-id |
ip-address }

By default, the RR uses its own
router ID as the cluster ID.

23.

Configure filtering of reflected
routes.

rr-filter
extended-community-number

By default, the RR does not filter
reflected routes.

Configuring inter-AS VPN

If the MPLS backbone spans multiple ASs, you must configure inter-AS VPN.

Configuring inter-AS option A

Inter-AS option A applies to scenarios with a few VPNs.
To configure inter-AS option A, create VPN instances on PEs and ASBRs. The VPN instances on PEs are

used to allow CEs to access the network. The VPN instances on ASBRs are used to access the peer ASBRs.
An ASBR considers the peer ASBR as a CE.
The route targets configured on the PEs must match those configured on the ASBRs in the same AS to

make sure VPN routes sent by the PEs (or ASBRs) can be received by the ASBRs (or PEs). Route targets

configured on the PEs in different ASs do not have such requirements.
For more information, see "

Configuring basic MPLS L3VPN

."

Configuring inter-AS option B

To configure inter-AS option B, configure PEs and ASBRs.

PE configuration:
Configure basic MPLS L3VPN, and specify the ASBR in the same AS as an MP-IBGP peer. The

route targets for the VPN instances on the PEs in different ASs must match for the same VPN. For
more information about PE configuration, see "

Configuring basic MPLS L3VPN

."

ASBR configuration:

{

Configure a routing protocol, and enable MPLS and LDP on the interface connecting to an
internal router of the AS.

{

Specify the PE in the same AS as an MP-IBGP peer, and the ASBR in a different AS as an
MP-EBGP peer.

{

Disable VPN target filtering for VPNv4 routes so the ASBR can maintain all VPNv4 routes and
advertise the routes to the peer ASBR.

{

Enable MPLS on the interface connected to the remote ASBRs. There is no need to configure a
label distribution protocol, for example, MPLS LDP.

An ASBR always sets itself as the next hop of VPNv4 routes advertised to an MP-IBGP peer regardless of
the peer next-hop-local command.
To configure inter-AS option B on an ASBR:

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