Administrator Guide

CONFIG-ROUTER-BGP mode
bgp non-deterministic-med
NOTE: When you change the best path selection method, path selection for existing paths remains unchanged until you
reset it by entering the clear ip bgp command in EXEC Privilege mode.
To view the BGP configuration, use the show config command in CONFIGURATION ROUTER BGP mode or the show
running-config bgp command in EXEC Privilege mode.
The following example shows how to configure values to reuse or restart a route. In the following example, default = 15 is
the set time before the value decrements, bgp dampening 2 ? is the set re-advertise value, bgp dampening 2 2000 ?
is the suppress value, and bgp dampening 2 2000 3000 ? is the time to suppress a route. Default values are also shown.
DellEMC(conf-router_bgp)#bgp dampening ?
<1-45> Half-life time for the penalty (default = 15)
route-map Route-map to specify criteria for dampening
<cr>
DellEMC(conf-router_bgp)#bgp dampening 2 ?
<1-20000> Value to start reusing a route (default = 750)
DellEMC(conf-router_bgp)#bgp dampening 2 2000 ?
<1-20000> Value to start suppressing a route (default = 2000)
DellEMC(conf-router_bgp)#bgp dampening 2 2000 3000 ?
<1-255> Maximum duration to suppress a stable route (default = 60)
DellEMC(conf-router_bgp)#bgp dampening 2 2000 3000 10 ?
route-map Route-map to specify criteria for dampening
<cr>
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).
DellEMC>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
DellEMC>
To view which routes are dampened (non-active), use the show ip bgp dampened-routes command in EXEC Privilege
mode.
Changing BGP keepalive and hold timers
BGP uses timers to control the activity of sending the keepalive messages to its neighbors or peers. Also, you can adjust the
interval of how long the device has to wait for a keepalive messge from a neighbor before declaring the peer dead. To configure
BGP timers, use either or both of the following commands.
To change the BGP timers for all neighbors, use timers bgp command. To change the BGP keepalive and holdtime timers for
a specific neighbor or peer, use the neighbor timers command.
NOTE:
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 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 configured keepalive value is the new
keepalive value.
● Configure timer values for a BGP neighbor or peer group.
Border Gateway Protocol (BGP)
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