Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.100.0 - Page 202

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. Dell(conf-router_bgp)#bgp dampening ? Half-life time for the penalty (default = 15) route-map Route-map to specify criteria for dampening Dell(conf-router_bgp)#bgp dampening 2 ? Value to start reusing a route (default = 750) Dell(conf-router_bgp)#bgp dampening 2 2000 ? Value to start suppressing a route (default = 2000) Dell(conf-router_bgp)#bgp dampening 2 2000 3000 ? Maximum duration to suppress a stable route (default = 60) Dell(conf-router_bgp)#bgp dampening 2 2000 3000 10 ? route-map Route-map to specify criteria for dampening 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 10.114.8.34 18508 82883 79977 780266 10.114.8.33 18508 117265 25069 780266 Dell> InQ OutQ Up/Down State/PfxRcd 0 2 00:38:51 118904 0 20 00:38:50 102759 To view which routes are dampened (non-active), use the show ip bgp dampened-routes command in EXEC Privilege mode. Changing BGP Timers To configure BGP timers, use either or both of the following commands. 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. 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. • Configure timer values for all neighbors. CONFIG-ROUTER-BGP mode timers bgp keepalive holdtime 202 Border Gateway Protocol IPv4 (BGPv4)