5-23message from its peer in a specific period (know as Holdtime), the router considers the BGP connectionoperates improperly and thus disconnects the BGP connection.When establishing a BGP connection, the two routers negotiate for the Holdtime by comparing theirHoldtime values and take the smaller one as the Holdtime.2) Limiting the number of route prefixes that can be learned from a peer/peer groupBy limiting the number of route prefixes that can be learned from peer/peer group to reduce the size ofthe local routing table, you can optimize the performance of the local router system and protect the localrouter.With this function enabled on a router, when the number of route prefixes learned from a peer/peergroup exceeds the configured value, the router automatically disconnects from the peer/peer group.3) BGP connection resetTo make a new BGP routing policy taking effect, you need to reset the BGP connection. This temporarilydisconnects the BGP connection. The switches support the BGP route-refresh function. Withroute-refresh function enabled on all the routers, if BGP routing policy changes, the local router sendsrefresh messages to its peers. And the peers receiving the message in turn send their routinginformation to the local router. Therefore, the local router can perform dynamic route update and applythe new policy without tearing down BGP connections.If a router not supporting route-refresh exists in the network, you can only reset BGP connections withthe refresh bgp command, resulting in temporary BGP disconnections.4) BGP authenticationBGP uses TCP as the transport layer protocol. To improve the security of BGP connections, you canspecify to perform MD5 authentication when a TCP connection is established. Note that the MD5authentication of BGP does not authenticate the BGP packets. It only configures the MD5authentication password for TCP connection, and the authentication is performed by TCP. Ifauthentication fails, the TCP connection cannot be established.Configuration PrerequisitesBefore adjusting the BGP clock, enable basic BGP functions.Before configuring BGP clock and authentication, make sure the following information is available.z Value of BGP timerz Interval for sending the update packetsz MD5 authentication passwordTuning and Optimizing a BGP NetworkFollow these steps to tune and optimize a BGP network:To do... Use the command... RemarksEnter system view system-view —Enter BGP view bgp as-number —ConfigureBGP timerConfigure the Keepalivetime and Holdtime ofBGP.timer keepalivekeepalive-interval holdholdtime-intervalOptionalBy default, the keepalive time is60 seconds, and holdtime is 180
