02-08-2015 05:27 PM - edited 03-05-2019 12:45 AM
Hello Team,
I've got few questions regarding the BGP 'Routing Information Sources' section under the bgp portion of 'show ip protocols'.
1) Why not all the bgp neighbors listed under 'Routing Information Sources'?
2) Are we supposed to see only configured neighbors under that section or other g/w ips as well?
3) What is that field for (actually)?
R1#sh ip bgp sum
BGP router identifier 192.168.1.253, local AS number 100
BGP table version is 338, main routing table version 338
337 network entries using 48528 bytes of memory
2353 path entries using 188240 bytes of memory
100/100 BGP path/bestpath attribute entries using 13600 bytes of memory
33 BGP AS-PATH entries using 1428 bytes of memory
47 BGP community entries using 1596 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 253392 total bytes of memory
1152 received paths for inbound soft reconfiguration
BGP activity 337/0 prefixes, 2354/1 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
192.168.1.3 4 200 692 585 338 0 0 00:39:19 288
192.168.1.4 4 200 692 585 338 0 0 00:39:20 288
192.168.1.19 4 200 690 585 338 0 0 00:39:10 288
192.168.1.20 4 200 690 585 338 0 0 00:39:13 288
R1#sh ip proto | s bgp
Redistributing: static, bgp 100
Routing Protocol is "bgp 100"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
IGP synchronization is disabled
Automatic route summarization is disabled
Neighbor(s):
Address FiltIn FiltOut DistIn DistOut Weight RouteMap
192.168.1.3 4000
192.168.1.4 2000
192.168.1.19 3000
192.168.1.20 1000
Maximum path: 2
Routing Information Sources:
Gateway Distance Last Update
192.168.1.3 20 00:41:47
Distance: external 20 internal 200 local 200
Redistributing: bgp 100, rip
R1#
Thanks& Regards,
George
Solved! Go to Solution.
02-09-2015 02:12 PM
Hello George,
it is because it appears the neighbor that is feeding the RIB, so the prefixes received from this neighbor are the best in the BGP table and therefore those ones that will be installed in the route table:
http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_pi/command/iri-cr-book/iri-cr-s1.html#wp3837273515
Routing Information Sources:
Lists all the routing sources that the Cisco IOS software is using to build its routing table. The following is displayed for each source:
Hope this helps,
Jose.
02-09-2015 02:12 PM
Hello George,
it is because it appears the neighbor that is feeding the RIB, so the prefixes received from this neighbor are the best in the BGP table and therefore those ones that will be installed in the route table:
http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_pi/command/iri-cr-book/iri-cr-s1.html#wp3837273515
Routing Information Sources:
Lists all the routing sources that the Cisco IOS software is using to build its routing table. The following is displayed for each source:
Hope this helps,
Jose.
02-10-2015 01:42 AM
Hello Jose,
Makes sense. I've verified all the received routes from those 4 neighbors and looks like all neighbors receiving same routes and 192.168.1.3 is the preferred path for all those routes as it has heigher weight:) I upgraded the device few days back and noticed that the other 3 neighbors disappeared from the routing information source after the upgrade (looks like uptime for that device was more than 1year and routes were preferred alternative paths whenever there was issues on the primary link- which is the reason they all appeared under the routing information source before the upgrade).
Cheers!
George
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