H3C Technologies H3C S10500 Series Switches - Manual (Page 267)

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• Configure each ASBR-PE, taking the peer ASBR-PE as its CE.
In other words, configure VPN instances on PEs and ASBR PEs respectively. The VPN instances on PEs are
used to allow CEs to access the network, and those on ASBR PEs are used to access the peer ASBR PEs.
For more information, see “
Configuring basic MPLS L3VPN .”
NOTE:
In the inter-AS option A solution, for the same VPN, the VPN targets configured on the PEs must match
those configured on the ASBR-PEs in the same AS to ensure that VPN routes sent by the PEs (or ASBR-PEs)
can be received by the ASBR-PEs (or PEs). VPN targets configured on the PEs in different ASs do not have
such requirements.
Configuring inter-AS option B
Follow these steps to configure inter-AS option B on ASBR PEs:
To do… Use the command… Remarks
Enter system view system-view —
Enter interface view for the
interface connecting to the remote
ASBR-PE
interface interface-type
interface-number
—
Configure the IP address of the
interface ip address ip-address { mask |
mask-length }
Required
Return to system view quit —
Enter BGP view bgp as-number —
Enter BGP-VPNv4 subaddress
family view
ipv4-family vpnv4 —
Disable VPN target based filtering
of VPNv4 routes
undo policy vpn-target
Required
By default, PE filters received
VPNv4 routes by VPN targets.
The routes surviving the filtering
will be added to the routing table,
and the others are discarded.
In the inter-AS option B solution, the ASBR PEs need to maintain all VPNv4 routing information and
advertise the information to peer ASBR PEs. In this case, the ASBR PEs must receive all VPNv4 routing
information without performing VPN target-based filtering.
In the inter-AS option B solution, for the same VPN, the VPN targets for the VPN instances on the PEs in
different ASs must match.