Hello,

Anukalp S · ‎11-26-2015

I am not sure why ospf is preferring route with higher metric(cost), see below logs and help me.

Preferred path

RTR#sh ip rou 192.168.33.1
Routing entry for 192.168.16.0/20, supernet
Known via "ospf 1", distance 110, metric 72, type inter area
Last update from 192.168.0.66 on Tunnel60, 00:31:48 ago
Routing Descriptor Blocks:
* 192.168.0.66, from 2.2.2.2, 00:31:48 ago, via Tunnel60
Route metric is 72, traffic share count is 1

Non preferred path

RTR#sh ip rou 192.168.33.1
Routing entry for 192.168.16.0/20, supernet
Known via "ospf 1", distance 110, metric 23, type inter area
Last update from 192.168.52.253 on GigabitEthernet0/0, 00:00:43 ago
Routing Descriptor Blocks:
* 192.168.52.253, from 11.1.1.1, 00:00:43 ago, via GigabitEthernet0/0
Route metric is 23, traffic share count is 1

RTR#sh ip os database | i 192.168.16.0
192.168.16.0    2.2.2.2         823         0x80002DED 0x004867
192.168.16.0    11.1.1.1        600         0x80000023 0x00FB90
192.168.16.0    192.168.52.254 1965        0x80000001 0x003BB2

Jon Marshall · ‎11-26-2015

I'm not sure I understand your output.

If the route is not being used then when you do a "sh ip ro 192.168.33.1" it wouldn't show that route.

But your output for the non preferred path shows that route being used by the router ie. it is in the IP routing table.

Can you clarify.

Jon

Anukalp S · ‎11-27-2015

Sorry, pls ignore previous logs. and see below correct.

RTR#sh ip rou 192.168.33.1 ------- prefer path eventhough metric(cost) is 72.
Routing entry for 192.168.33.0/20, supernet
Known via "ospf 1", distance 110, metric 72, type inter area
Last update from 192.168.0.66 on Tunnel60, 00:31:48 ago
Routing Descriptor Blocks:
* 192.168.0.66, from 2.2.2.2, 00:31:48 ago, via Tunnel60
Route metric is 72, traffic share count is 1

RTR#sh ip rou 192.168.33.1 ----------- not prefer path eventhough metric(cost) is 23.
Routing entry for 192.168.33.0/20, supernet
Known via "ospf 1", distance 110, metric 23, type inter area
Last update from 192.168.52.253 on GigabitEthernet0/0, 00:00:43 ago
Routing Descriptor Blocks:
* 192.168.52.253, from 11.1.1.1, 00:00:43 ago, via GigabitEthernet0/0
Route metric is 23, traffic share count is 1

RTR#traceroute 192.168.33.1

Type escape sequence to abort.
Tracing the route to 192.168.33.1

1 192.168.0.66 224 msec 220 msec 224 msec
2 192.168.80.25 248 msec * 224 msec
3 192.168.80.10 224 msec 272 msec 244 msec
4 192.168.0.9 452 msec 448 msec 448 msec
5 192.168.80.201 440 msec * 444 msec

RTR#sh ip os data | i 192.168.33.0
192.168.33.0    2.2.2.2         905         0x80002E0D 0x000788
192.168.33.0    11.1.1.1        327         0x80000043 0x00BBB0
192.168.33.0    192.168.52.254 999         0x80000025 0x00F2D6

Pls tell me why route to 192.168.33.1 preferring path over 192.168.0.66 eventhough cost to this path is high.

Jon Marshall · ‎11-27-2015

You haven't answered Masoud's question and you have completely ignored mine.

Can't really help if you won't answer the questions.

So if the router is using the path via the tunnel then you should only see that route when you do a "sh ip route 192.168.33.1" but your output also shows it via the other path as well.

192.168.33.0/20 is not a valid supernet entry, are you modifying the output ?

Jon

Anukalp S · ‎11-29-2015

Sorry Jon & Masoud, seems logs were pasted wrong here, pls find below output logs and suggest on this.

I still dont understand why metric 72 is chosen best over 23 in ospf.

RTR#sh ip rou 192.168.16.1 ------- prefer path eventhough metric(cost) is 72.
Routing entry for 192.168.16.0/20, supernet
Known via "ospf 1", distance 110, metric 72, type inter area
Last update from 192.168.0.66 on Tunnel60, 00:31:48 ago
Routing Descriptor Blocks:
* 192.168.0.66, from 2.2.2.2, 00:31:48 ago, via Tunnel60
Route metric is 72, traffic share count is 1

RTR#sh ip rou 192.168.16.1 ----------- not prefer path eventhough metric(cost) is 23.
Routing entry for 192.168.16.0/20, supernet
Known via "ospf 1", distance 110, metric 23, type inter area
Last update from 192.168.52.253 on GigabitEthernet0/0, 00:00:43 ago
Routing Descriptor Blocks:
* 192.168.52.253, from 11.1.1.1, 00:00:43 ago, via GigabitEthernet0/0
Route metric is 23, traffic share count is 1

RTR#traceroute 192.168.16.1

Type escape sequence to abort.
Tracing the route to 192.168.16.1

1 192.168.0.66 224 msec 220 msec 224 msec
2 192.168.80.25 248 msec * 224 msec
3 192.168.80.10 224 msec 272 msec 244 msec
4 192.168.0.9 452 msec 448 msec 448 msec
5 192.168.80.201 440 msec * 444 msec

RTR#sh ip os data | i 192.168.16.0
192.168.16.0    2.2.2.2         905         0x80002E0D 0x000788
192.168.16.0    11.1.1.1        327         0x80000043 0x00BBB0
192.168.16.0    192.168.52.254 999         0x80000025 0x00F2D6

RTR#sh ip rou | i 192.168.16.0
O IA 192.168.16.0/20 [110/72] via 192.168.0.66, 2d03h, Tunnel60

Masoud Pourshabanian · ‎11-26-2015

Hello,

Can you share the output of "show IP route | include 192.168.33.1

If Tunnel is down, the other route via GigabitEthernet0/0 sits inside the routing table?

Masoud

ospf preference