Configuring Inter-As Option B - HP FlexNetwork 10500 Series Configuration Manual

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 inter-AS option B

To configure inter-AS option B, perform configurations on 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 information about PE configuration, see
•
ASBR configuration:
Configure a routing protocol, and enable MPLS and LDP on the interface connected 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 capability on the interface connected to the ASBR in another AS. There is no

need to configure a label distribution protocol, for example, 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:
Step
1. Enter system view.
2. Enter interface view of the
interface connected to an
internal router of the AS.
3. Enable MPLS on the
interface.
4. Enable MPLS LDP on the
interface.
5. Return to system view.
6. Enter interface view of the
interface connected to the
remote ASBR.
7. Enable MPLS on the
interface.
8. Return to system view.
9. Enter BGP instance view.
10. Create a BGP peer.
11. Enter BGP VPNv4 address
family view.
"Configuring basic MPLS
Command
system-view
interface interface-type
interface-number
mpls enable
mpls ldp enable
quit
interface interface-type
interface-number
mpls enable
quit
bgp as-number [ instance
instance-name ]
peer { group-name | ipv4-address
[ mask-length ] } as-number
as-number
address-family vpnv4
212
L3VPN."
"Configuring basic MPLS
Remarks
N/A
N/A
By default, MPLS is disabled on
the interface.
By default, MPLS LDP is disabled
on the interface.
N/A
N/A
By default, MPLS is disabled on
the interface.
N/A
N/A
By default, no BGP peers exist.
Configure PEs in the same AS as
IBGP peers, and ASBRs in
different ASs as EBGP peers.
N/A
L3VPN."