H3C Technologies H3C S7500E Series Switches - Manual (Page 269)

6-44
To do… Use the command… Remarks
Enter system view system-view —
Enter BGP view bgp as-number —
Enter BGP-VPNv4 subaddress
family view
ipv4-family vpnv4 Required
Enable the exchange of
BGP-VPNv4 routing information
with a peer
peer { group-name | ip-address }
enable
Required
Specify a BGP peer or peer group
as the UPE
peer { group-name | ip-address }
upe
Required
Specify to advertise default routes
of a VPN instance to a UPE
peer { group-name | ip-address }
default-route-advertise
vpn-instance vpn-instance-name
Specify to advertise routes
permitted by a specified routing
policy to a UPE
peer { group-name | ip-address }
upe route-policy
route-policy-name export
Required
Configure either command.
By default, BGP does not
advertise default routes to a
VPNv4 peer.
With the peer default-route-advertise vpn-instance command configured, the SPE always
advertises a default route using the local address as the next hop address to the UPE, regardless of
whether the default route is present in the local routing table or not.
z
The default routes of a VPN instance can be advertised to only a BGP peer or peer group that is
UPE.
z
It is not recommended to configure the peer default-route-advertise vpn-instance command
and the peer upe route-policy command at the same time.
z
It is not recommended for an SPE to be connected to a CE directly. If an SPE must be directly
connected with a CE, the VPN instance on the SPE and that on the UPE must be configured with
different RDs.
Configuring OSPF Sham Link
The sham link is considered an OSPF intra-area route. It is used to ensure that the VPN traffic is
transmitted over the backbone instead of the backdoor link between two CEs.
The source and destination addresses of the sham link must be loopback interface addresses with
32-bit masks. Besides, the loopback interfaces must be bound to the VPN instances and be
advertised through BGP.