Configuring Inter-As Option C - HP 10500 SERIES Configuration Manual

Configuring inter-AS option C

To configure inter-AS option C, perform proper configurations on PEs and ASBR PEs, and configure
routing policies on the ASBR PEs.
Configuring the PEs
You must establish an ordinary IBGP peer relationship between PEs and ASBR PEs in an AS and
MP-EBGP peer relationship between PEs of different ASs.
The PEs and ASBR PEs in an AS must be able to exchange labeled IPv4 routes.
To configure a PE for inter-AS option C:
Step
1. Enter system view.
2. Enter BGP view.
3. Configure the ASBR PE in the
same AS as the IBGP peer.
4. Enable the PE to exchange
labeled IPv4 routes with the
ASBR PE in the same AS.
5. Configure the PE of another
AS as the EBGP peer.
6. Enter BGP-VPNv4 subaddress
family view.
7. Enable the PE to exchange
BGP VPNv4 routing
information with the EBGP
peer.
8. Configure the PE not to
change the next hop of a
route when advertising it to
the EBGP peer.
Configuring the ASBR PEs
In the inter-AS option C solution, an inter-AS LSP is required, and the routes advertised between the
relevant PEs and ASBRs must carry MPLS label information.
An ASBR-PE establishes common IBGP peer relationship with PEs in the same AS, and common EBGP
peer relationship with the peer ASBR PE. All of them exchange labeled IPv4 routes.
The public routes carrying MPLS labels are advertised through MP-BGP. According to RFC 3107
"Carrying Label Information in BGP-4," the label mapping information for a particular route is
piggybacked in the same BGP update message that is used to distribute the route itself. This capability
is implemented through BGP extended attributes and requires that the BGP peers can handle labeled
IPv4 routes.
To configure an ASBR PE for inter-AS option C:
Command
system-view
bgp as-number
peer { group-name | ip-address }
as-number as-number
peer { group-name | ip-address }
label-route-capability
peer { group-name | ip-address }
as-number as-number
ipv4-family vpnv4
peer { group-name | ip-address }
enable
peer { group-name | ip-address }
next-hop-invariable
264
Remarks
N/A
N/A
N/A
By default, the device does not
advertise labeled routes to the IPv4
peer or peer group.
N/A
N/A
N/A
Optional.
Required only when RRs are used
to advertise VPNv4 routes, where
the next hop of a route advertised
between RRs cannot be changed.