Controlling the Learning and Advertising of VPN Routes on ASBR

An ASBR can either save partial VPNv6 routes by filtering VPN targets through a routing policy or save all VPNv6 routes.

Context

By default, an ASBR filters received VPNv6 routes based on VPN targets. The matching routes are imported into the routing table; otherwise, they are discarded. Therefore, if no VPN instance is configured on the ASBR or no VPN target is configured for the VPN instance, the ASBR discards all the received VPNv6 routes.

Either of the following methods can be used:

An ASBR can be disabled from filtering routes based on VPN targets. After this configuration, the ASBR saves all VPNv6 routes.
An ASBR can be enabled to filter routes based on VPN targets. A route-policy can be configured so that only BGP VPNv6 routes matching the policy are accepted.

Perform either of the following methods on the ASBR as needed.

Procedure

Enable the ASBR to accept VPN routes without filtering them based on VPN targets.
1. Run system-view
  The system view of the ASBR is displayed.
2. Run bgp as-number
  The BGP view is displayed.
3. Run ipv6-family vpnv6 [ unicast ]
  The BGP-VPN IPv6 address family view is displayed.
4. Run undo policy vpn-target
  Filtering VPN targets of VPNv6 routes is disabled.
  
  In inter-AS VPN Option B mode, the ASBR does not need to store VPN instance information but must store information about all VPNv6 routing information and advertise the routing information to the peer ASBR. In this case, the ASBR needs to import all received VPNv6 routing information without filtering them based on VPN targets.
5. Run commit
  The configuration is committed.
Configure a route-policy to filter VPN routes based on VPN targets.
1. Run system-view
  The system view is displayed on the ASBR.
2. Perform either of the following operations as required to configure an extcommunity filter.
  - To configure a basic extcommunity filter, run the ip extcommunity-filter { basic-extcomm-filter-num | basic basic-extcomm-filter-name } { deny | permit } { rt { as-number:nn | 4as-number:nn | ipv4-address:nn } } &<1-16> command.
  - To configure an advanced extcommunity filter, run the ip extcommunity-filter { advanced-extcomm-filter-num | advanced advanced-extcomm-filter-name } { deny | permit } regular-expression command.
3. Run route-policy route-policy-name permit node node
  A route-policy is configured.
4. Run if-match extcommunity-filter { { basic-extcomm-filter-num | adv-extcomm-filter-num } &<1-16> | basic-extcomm-filter-name | advanced-extcomm-filter-name }
  A match rule based on the export-filter is configured.
5. Run commit
  The configuration is committed.
6. Run quit
  Return to the system view.
7. Run bgp as-number
  The BGP view is displayed.
8. Run ipv6-family vpnv6 [ unicast ]
  The BGP-VPN IPv6 address family view is displayed.
9. Run peer ipv4-address route-policy policy-name { export | import }
  The route-policy is used to controlling the importing or exporting of VPNv6 routes.
10. Run commit
  The configuration is committed.