Hi All,
I just wanted to double check something on this question. I was testing what happens when you don't have the aggregate routes configured. I notice that when I don't have the aggregates (155.16.0.0/16 in my case) towards the backbones, when I traceroute from SW4 it stops at R4.
Rack16SW4#tracer 112.0.0.1
Type escape sequence to abort.
Tracing the route to 112.0.0.1
1 155.16.108.8 4 msec 4 msec 0 msec
2 155.16.58.5 4 msec 0 msec 4 msec
3 155.16.0.3 28 msec 32 msec 28 msec
4 155.16.13.1 36 msec 32 msec 36 msec
5 155.16.146.4 32 msec 36 msec 36 msec
6 * * *
7 *
My confusion is with why the packet stops at R4. R4 can recurse to 112.0.0.1.
Rack16R4(config-router)#do show ip route 112.0.0.1
Routing entry for 112.0.0.0/8
Known via "bgp 100", distance 20, metric 0
Tag 54, type external
Last update from 204.12.16.254 01:12:11 ago
Routing Descriptor Blocks:
* 204.12.16.254, from 204.12.16.254, 01:12:11 ago
Route metric is 0, traffic share count is 1
AS Hops 3
Route tag 54
Rack16R4(config-router)#do show ip route 204.12.16.254
Routing entry for 204.12.16.0/24
Known via "connected", distance 0, metric 0 (connected, via interface)
Routing Descriptor Blocks:
* directly connected, via FastEthernet0/0
Route metric is 0, traffic share count is 1
I understand that without the aggregate, the packet wouldn't know how to get back from 112.0.0.1. I'm confused on why it stops at R4. I'm sure I'm missing something simple, so thanks in advance for the help.
- Kevin