RIP Routing Database switches between two best paths

June 30, 2006 @ 11:59 pm · Filed under CCIE Study

Hi,
I am seeing a weird output in the debug just for one set of target routes. Could you say whats wrong from below ?
Problem: At “debug ip routing”. 150.1.1.1 is constantly changing the best nexthop from s0/0 e0/0 of R2 on R3. This problem doesnt happen for other routes though. (ex:150.1.6.6)
Taken from IEWB v3, lab 9, task 4.8
000528: *May 31 08:30:31.097: RT: SET_LAST_RDB for 150.1.1.0/24 OLD rdb: via 148.1.0.1, Serial1/0.302 NEW rdb: via 192.10.1.2, FastEthernet0/1
Topology:
R1 (150.1.1.1)———-(s0/0) R2 (s0/0)———(s1/0.302)R3. | | e0/0—————————e0/1
R3 Info:
Rack1R3#sir 150.1.6.6 Routing entry for 150.1.6.6/32 Known via “rip”, distance 120, metric 2 Redistributing via eigrp 100, rip Advertised by eigrp 100 metric 10000 1000 255 1 1500 Last update from 148.1.0.1 on Serial1/0.302, 00:00:11 ago Routing Descriptor Blocks: 192.10.1.2, from 192.10.1.2, 00:00:11 ago, via FastEthernet0/1 Route metric is 2, traffic share count is 1 * 148.1.0.1, from 148.1.0.2, 00:00:11 ago, via Serial1/0.302 Route metric is 2, traffic share count is 1
Rack1R3#sir 150.1.1.1 Routing entry for 150.1.1.0/24 Known via “rip”, distance 120, metric 2 Redistributing via eigrp 100, rip Advertised by eigrp 100 metric 10000 1000 255 1 1500 Last update from 148.1.0.1 on Serial1/0.302, 00:00:13 ago Routing Descriptor Blocks: 192.10.1.2, from 192.10.1.2, 00:00:13 ago, via FastEthernet0/1 Route metric is 2, traffic share count is 1 * 148.1.0.1, from 148.1.0.2, 00:00:13 ago, via Serial1/0.302 Route metric is 2, traffic share count is 1
Rack1R3#sir 150.1.6.6 Routing entry for 150.1.6.6/32 Known via “rip”, distance 120, metric 2 Redistributing via eigrp 100, rip Advertised by eigrp 100 metric 10000 1000 255 1 1500 Last update from 148.1.0.1 on Serial1/0.302, 00:00:15 ago Routing Descriptor Blocks: 192.10.1.2, from 192.10.1.2, 00:00:15 ago, via FastEthernet0/1 Route metric is 2, traffic share count is 1 * 148.1.0.1, from 148.1.0.2, 00:00:15 ago, via Serial1/0.302 Route metric is 2, traffic share count is 1
Rack1R3#sir 150.1.1.1 Routing entry for 150.1.1.0/24 Known via “rip”, distance 120, metric 2 Redistributing via eigrp 100, rip Advertised by eigrp 100 metric 10000 1000 255 1 1500 Last update from 148.1.0.1 on Serial1/0.302, 00:00:18 ago Routing Descriptor Blocks: * 192.10.1.2, from 192.10.1.2, 00:00:18 ago, via FastEthernet0/1 Route metric is 2, traffic share count is 1 148.1.0.1, from 148.1.0.2, 00:00:18 ago, via Serial1/0.302 Route metric is 2, traffic share count is 1
Rack1R3#sir 150.1.6.6 Routing entry for 150.1.6.6/32 Known via “rip”, distance 120, metric 2 Redistributing via eigrp 100, rip Advertised by eigrp 100 metric 10000 1000 255 1 1500 Last update from 148.1.0.1 on Serial1/0.302, 00:00:20 ago Routing Descriptor Blocks: 192.10.1.2, from 192.10.1.2, 00:00:21 ago, via FastEthernet0/1 Route metric is 2, traffic share count is 1 * 148.1.0.1, from 148.1.0.2, 00:00:20 ago, via Serial1/0.302 Route metric is 2, traffic share count is 1
Rack1R3#

R 150.1.4.0/24 [120/3] via 192.10.1.2, 00:00:20, FastEthernet0/1 [120/3] via 148.1.0.4, 00:00:20, Serial1/0.302 C 150.1.3.0/24 is directly connected, Loopback0 R 150.1.2.0/24 [120/1] via 192.10.1.2, 00:00:20, FastEthernet0/1 [120/1] via 148.1.0.2, 00:00:20, Serial1/0.302 R 150.1.1.0/24 [120/2] via 192.10.1.2, 00:00:20, FastEthernet0/1 [120/2] via 148.1.0.1, 00:00:20, Serial1/0.302 R 150.1.8.8/32 [120/2] via 192.10.1.2, 00:00:20, FastEthernet0/1 [120/2] via 148.1.0.1, 00:00:20, Serial1/0.302 R 150.1.6.6/32 [120/2] via 192.10.1.2, 00:00:21, FastEthernet0/1 [120/2] via 148.1.0.1, 00:00:21, Serial1/0.302
Routing Protocol is “rip” Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Sending updates every 30 seconds, next due in 22 seconds Invalid after 180 seconds, hold down 180, flushed after 240 Redistributing: eigrp 100, rip Default version control: send version 2, receive version 2 Interface Send Recv Triggered RIP Key-chain FastEthernet0/1 2 2 Serial1/0.302 2 2 Automatic network summarization is not in effect Maximum path: 4 Routing for Networks: 148.1.0.0 150.1.0.0 192.10.1.0 Passive Interface(s): FastEthernet0/0 Serial1/0 Serial1/1 Serial1/2 Serial1/3 Serial1/4 Serial1/5 Serial1/6 Serial1/7 Loopback0 Tunnel0 Tunnel3456 VoIP-Null0 Routing Information Sources: Gateway Distance Last Update 148.1.0.2 120 00:00:13 192.10.1.2 120 00:00:14 Distance: (default is 120) ! router rip version 2 redistribute eigrp 100 metric 1 passive-interface default no passive-interface FastEthernet0/1 no passive-interface Serial1/0.302 network 148.1.0.0 network 150.1.0.0 network 192.10.1.0 no auto-summary !

– Thanks & Rgds SAN

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