H3C Technologies H3C S10500 Series Switches - Manual (Page 269)

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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-AS option C:
To do… Use the command… Remarks
Enter system view system-view —
Enter BGP view bgp as-number —
Configure each PE in the same AS
as the iBGP peer peer { group-name | ip-address }
as-number as-number
Required
Enable the ASBR PE to exchange
labeled IPv4 routes with the PEs in
the same AS
peer { group-name | ip-address }
label-route-capability
Required
By default, the device does not
advertise labeled routes to the IPv4
peer or peer group.
Configure the ASBR PE to change
the next hop to itself when
advertising routes to PEs in the
same AS
peer { group-name | ip-address }
next-hop-local
Required
By default, a BGP speaker does not
use its address as the next hop
when advertising a route to its
iBGP peer or peer group.
Configure the remote ASBR PE as
the eBGP peer peer { group-name | ip-address }
as-number as-number
Required
Enable the ASBR PE to exchange
labeled IPv4 routes with the peer
ASBR PE
peer { group-name | ip-address }
label-route-capability
Required
By default, the device does not
advertise labeled routes to the IPv4
peer.
Apply a routing policy to the routes
advertised by peer ASBR PE
peer { group-name | ip-address }
route-policy route-policy-name
export Required
By default, no routing policy is
applied to a peer or peer group.
Configuring the routing policy
After you configure and apply a routing policy on an ASBR PE, it does the following:
• 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.
Follow these steps to configure a routing policy for inter-AS option C on an ASBR PE:
To do… Use the command… Remarks
Enter system view system-view —
Enter routing policy view
route-policy policy-name permit
node seq-number
Required