Tuning and optimizing IPv6 BGP networks

This section describes configurations of IPv6 BGP timers, IPv6 BGP connection soft reset, and the maximum number of load balanced routes.

• IPv6 BGP timers

  After establishing an IPv6 BGP connection, two routers send keepalive messages periodically to each other to maintain the connection. If a router receives no keepalive message from the peer after the holdtime elapses, it tears down the connection.

  When establishing an IPv6 BGP connection, the two parties compare their holdtimes, taking the shorter one as the common holdtime. If the holdtime is 0, neither keepalive massage is sent, nor holdtime is checked.

• IPv6 BGP connection soft reset

  After modifying a route selection policy, you must reset IPv6 BGP connections to make the new one take effect. The current IPv6 BGP implementation supports the route-refresh feature that enables dynamic route refresh without needing to disconnect IPv6 BGP links.

  After this feature is enabled on all IPv6 BGP routers, a router that wants to apply a new route selection policy advertises a route-refresh message to its peers, which then send their routing information to the router. After receiving the routing information, the router can perform dynamic route update by using the new policy without tearing down connections.

  If a peer not supporting route-refresh exists in the network, you must configure the peer keep-all-routes command to save all routes from the peer. When the routing policy is changed, the system will update the IPv6 BGP routing table and apply the new policy.