Users Guide

To view a count of dampened routes, history routes, and penalized routes when you enable route dampening, look at the seventh line
of the show ip bgp summary command output, as shown in the following example (bold).
Dell>show ip bgp summary
BGP router identifier 10.114.8.131, local AS number 65515
BGP table version is 855562, main routing table version 780266
122836 network entrie(s) and 221664 paths using 29697640 bytes of memory
34298 BGP path attribute entrie(s) using 1920688 bytes of memory
29577 BGP AS-PATH entrie(s) using 1384403 bytes of memory
184 BGP community entrie(s) using 7616 bytes of memory
Dampening enabled. 0 history paths, 0 dampened paths, 0 penalized paths
Neighbor AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
10.114.8.34 18508 82883 79977 780266 0 2 00:38:51 118904
10.114.8.33 18508 117265 25069 780266 0 20 00:38:50 102759
Dell>
To view which routes are dampened (non-active), use the show ip bgp dampened-routes command in EXEC Privilege mode.
Changing BGP Timers
To congure BGP timers, use either or both of the following commands.
Timer values congured with the neighbor timers command override the timer values congured with the timers bgp
command.
When two neighbors, congured with dierent keepalive and holdtime values, negotiate for new values, the resulting values
are 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 congured keepalive value is the new
keepalive value.
• Congure timer values for a BGP neighbor or peer group.
CONFIG-ROUTER-BGP mode
neighbors {ip-address | peer-group-name} timers keepalive holdtime
– keepalive: the range is from 1 to 65535. Time interval, in seconds, between keepalive messages sent to the neighbor
routers. The default is 60 seconds.
– holdtime: the range is from 3 to 65536. Time interval, in seconds, between the last keepalive message and declaring the
router dead. The default is
180 seconds.
• Congure timer values for all neighbors.
CONFIG-ROUTER-BGP mode
timers bgp keepalive holdtime
– keepalive: the range is from 1 to 65535. Time interval, in seconds, between keepalive messages sent to the neighbor
routers. The default is
60 seconds.
– holdtime: the range is from 3 to 65536. Time interval, in seconds, between the last keepalive message and declaring the
router dead. The default is 180 seconds.
To view non-default values, use the show config command in CONFIGURATION ROUTER BGP mode or the show running-
config bgp command in EXEC Privilege mode.
Enabling BGP Neighbor Soft-Reconguration
BGP soft-reconguration allows for faster and easier route changing.
Changing routing policies typically requires a reset of BGP sessions (the TCP connection) for the policies to take eect. Such resets
cause undue interruption to trac due to hard reset of the BGP cache and the time it takes to re-establish the session. BGP soft
recong allows for policies to be applied to a session without clearing the BGP Session. Soft-recong can be done on a per-neighbor
basis and can either be inbound or outbound.
Border Gateway Protocol IPv4 (BGPv4)
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