Dell Force10 Z9000 FTOS Configuration Guide for Z9000 System - Page 221

Change BGP timers Use either or both of the following commands in the CONFIGURATION ROUTER BGP mode to configure BGP timers. Command Syntax Command Mode Purpose neighbors {ip-address | peer-group-name} timers keepalive holdtime CONFIG-ROUTER-BGP Configure timer values for a BGP neighbor or peer group. • keepalive range: 1 to 65535. Time interval, in seconds, between keepalive messages sent to the neighbor routers. (Default: 60 seconds) • holdtime range: 3 to 65536. Time interval, in seconds, between the last keepalive message and declaring the router dead. (Default: 180 seconds) timers bgp keepalive holdtime CONFIG-ROUTER-BGP Configure timer values for all neighbors. • keepalive range: 1 to 65535. Time interval, in seconds, between keepalive messages sent to the neighbor routers. (Default: 60 seconds) • holdtime range: 3 to 65536. Time interval, in seconds, between the last keepalive message and declaring the router dead. (Default: 180 seconds) Use the show config command in CONFIGURATION ROUTER BGP mode or the show running-config bgp command in EXEC Privilege mode to view non-default values. Timer values configured with the neighbor timers command override the timer values configured with the timers bgp command. When two neighbors, configured with different keepalive and holdtime values, negotiate for new values, the resulting values will be as follows: • the lower of the holdtime values is the new holdtime value, and • whichever is the lower value; one-third of the new holdtime value, or the configured keepalive value is the new keepalive value. BGP neighbor soft-reconfiguration Changing routing policies typically requires a reset of BGP sessions (the TCP connection) for the policies to take effect. Such resets cause undue interruption to traffic due to hard reset of the BGP cache and the time it takes to re-establish the session. BGP soft reconfig allows for policies to be applied to a session without clearing the BGP Session. Soft-reconfig can be done on a per-neighbor basis and can either be inbound or outbound. BGP Soft Reconfiguration clears the policies without resetting the TCP connection. Border Gateway Protocol | 221