Configuring BGP4+ to Advertise Default Routes to Peers or peer groups

A device sends a default route with the local address as the next hop address to the specified peer for load balancing, regardless of whether there are default routes in the local routing table. This greatly reduces the number of routes on the network.

Context

Default routes can be used on networks that have the following characteristics:

There are multiple EBGP peers, and each peer can receive full Internet routes.
There are multiple Route Reflectors (RRs), and each RR can receive full Internet routes.

When load balancing is not performed on the network, a BGP4+ peer receives at most one copy of active full Internet routes. After load balancing is performed on the network, the number of active routes received by the BGP4+ peer doubles, which causes the number of routes on the network to sharply increase. In this case, you can configure the local device to advertise only default routes to its BGP4+ peer and use default routes for load balancing, which can greatly reduce the number of routes on the network.

Procedure

Run system-view
The system view is displayed.
Run bgp as-number
The BGP view is displayed.
Run ipv6-family unicast
The IPv6 unicast address family view is displayed.
Run peer { ipv4-address | ipv6-address | group-name } default-route-advertise [ route-policy route-policy-name | route-filter route-filter-name ] [ conditional-route-match-all { ipv6-address1 ipv6-mask-length1 } &<1-4> | conditional-route-match-any { ipv6-address2 ipv6-mask-length2 } &<1-4> ]
Default routes are sent to a remote peer or peer group.

If route-policy route-policy-name or route-filter route-filter-name is set, the BGP device changes attributes of the default route based on the specified route policy.

If conditional-route-match-all { ipv6-address1 ipv6-mask-length1 } &<1-4> is set, the BGP device sends the default route to the peer only when routes that match all the all specified conditions exist in the local IPv6 routing table.

If conditional-route-match-any { ipv6-address2 ipv6-mask-length2 } &<1-4> is set, the local device sends a default route to the peer when routes that match any of the specified conditions exist in the local IPv6 routing table.

After the peer default-route-advertise command is run, BGP4+ sends a default route with the local address as the next hop to the specified peer, regardless of whether there are default routes in the routing table.
Run commit
The configuration is committed.