Configuring BGP4+ to Generate a Summary Default Route

You can configure BGP4+ to generate a summary default route and then determine whether to advertise the default route to a peer by using a route-policy.

Usage Scenario

On the network shown in Figure 1, a BGP-VPNv6 peer relationship is established between PE1 and PE2. In addition, an EBGP-VPN peer relationship is established between PE2 and the core network device, and another EBGP-VPN peer relationship is established between PE1 and CE1. The core network device advertises routes to PE2 through the EBGP-VPN peer relationship. PE2 then advertises the received routes to PE1 through the BGP-VPNv6 peer relationship. Upon receipt, PE1 leaks the routes to its VPN instance. A summary default route can be generated only if routes with a specific prefix exist among the leaked routes. You can configure BGP4+ to generate a summary default route on PE1 so that PE1 matches the leaked routes against an IP prefix list and summarizes the matched routes into a default route. As a result, PE1 advertises only the summary default route to CE1. Traffic over the unmatched routes will not be diverted to PE1, thereby conserving PE1's bandwidth resources.

Figure 1 Typical networking

Pre-configuration Tasks

Before configuring BGP4+ to generate a summary default route, configure basic BGP4+ functions.

Procedure

Run system-view
The system view is displayed.
Run ip ipv6-prefix ipv6-prefix-name [ index index-number ] matchMode ipv6-address masklen [ match-network ] [ greater-equal greater-equal-value ] [ less-equal less-equal-value ]
An IPv6 prefix list is configured.
Run bgp as-number
The BGP view is displayed.
Run ipv6-family unicast
The IPv6 unicast address family view is displayed.
Run aggregate default-route origin-ipv6-prefix ipv6-prefix-name [ attribute-policy attribute-policy-name ]
BGP is enabled to generate a summary default route based on an IPv6 prefix list.
Run commit
The configuration is committed.

Verifying the Configuration

After the configuration is complete, verify the configuration.

Run the display bgp ipv6 routing-table 0::0 command to check BGP4+ summary default route information.