339To do… Use the command… RemarksConfigure to carry only the publicAS number in updates sent to apeer or peer grouppeer { ipv6-group-name |ipv6-address } public-as-onlyOptionalBy default, IPv6 BGP updates carrya private AS number.Substitute the local AS number forthe AS number of an IPv6 peer orpeer group identified in theAS_PATH attributepeer { ipv6-group-name |ipv6-address } substitute-asOptionalNot substituted by defaultTuning and optimizing IPv6 BGP networksThis section describes configurations of IPv6 BGP timers, IPv6 BGP connection soft reset, and themaximum number of load balanced routes.• IPv6 BGP timersAfter establishing an IPv6 BGP connection, two routers send keepalive messages periodically to eachother to maintain the connection. If a router receives no keepalive message from the peer after theholdtime elapses, it tears down the connection.When establishing an IPv6 BGP connection, the two parties compare their holdtimes, taking the shorterone as the common holdtime. If the holdtime is 0, neither keepalive massage is sent, nor holdtime ischecked.• IPv6 BGP connection soft resetAfter modifying a route selection policy, you must reset IPv6 BGP connections to make the new one takeeffect. The current IPv6 BGP implementation supports the route-refresh feature that enables dynamic routerefresh 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 selectionpolicy advertises a route-refresh message to its peers, which then send their routing information to therouter. After receiving the routing information, the router can perform dynamic route update by using thenew policy without tearing down connections.If a peer not supporting route-refresh exists in the network, you must configure the peer keep-all-routescommand to save all routes from the peer. When the routing policy is changed, the system will update theIPv6 BGP routing table and apply the new policy.Configuration prerequisitesBefore configuring IPv6 BGP timers, complete the following tasks:• Enable IPv6• Configure IPv6 BGP basic functionsConfiguring IPv6 BGP timersFollow these steps to configure IPv6 BGP timers:To do… Use the command… RemarksEnter system view system-view —Enter BGP view bgp as-number —
