3Com S7906E Configuration Manual page 1553

Configuring the ASBR PEs
In the inter-provider VPN option C solution, an inter-provider VPN 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.
Follow these steps to configure an ASBR PE for inter-provider VPN option C:
To do...
Enter system view
Enter BGP view
Configure each PE in the same
AS as the IBGP peer
Enable the ASBR PE to
exchange labeled IPv4 routes
with the PEs in the same AS
Configure the ASBR PE to
change the next hop to itself
when advertising routes to PEs
in the same AS
Configure the remote ASBR PE
as the EBGP peer
Enable the ASBR PE to
exchange labeled IPv4 routes
with the peer ASBR PE
Apply a routing policy to the
routes advertised by peer
ASBR PE
Configuring the routing policy
After you configure and apply a routing policy on an ASBR PE, it:
Assigns MPLS labels to the routes received from the PEs in the same AS before advertising them
to the peer ASBR PE.
Assigns new MPLS labels to the labeled IPv4 routes to be advertised to the PEs in the same AS.
Which IPv4 routes are to be assigned with MPLS labels depends on the routing policy. Only routes that
satisfy the criteria are assigned with labels. All the other routes are still common IPv4 routes.
Use the 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 } next-hop-local
peer { group-name |
ip-address } as-number
as-number
peer { group-name |
ip-address }
label-route-capability
peer { group-name |
ip-address } route-policy
route-policy-name export
1-38
Remarks
—
—
Required
Required
By default, the device does not
advertise labeled routes to the
IPv4 peer/peer group.
Required
By default, a BGP speaker
does not use its address as the
next hop when advertising a
route to its IBGP peer/peer
group.
Required
Required
By default, the device does not
advertise labeled routes to the
IPv4 peer.
Required
By default, no routing policy is
applied to a peer or peer group.