RIP database redistribured

francisco_1 · ‎02-10-2009

I am advertising a loopback from a router and the mask on the loopback is same as the interface sending out the RIP updates.

for example

r1

int loopback 0

ip add 192.168.254.1 255.0.0.0

int serial 1/0

ip address 12.0.0.1 255.0.0.0 (this interface sending/receiving RIP updates)

The problem is the other RIP router is not receiving the RIP update for 192.168.254.0 subnet when the mask is the same as the serial. my understanding is if the update for 192.168.254.0 is not the same major network as the interafce advertising the update, then it advertise the update despite the mask being the same??? since ripv1 is a classful, it should advertise 192.168.254.0 as /24?

this is what i'm seeing on r1

r1#sh ip rip database

192.0.0.0/8 redistributed

[0] via 0.0.0.0,

Francisco.

mahmoodmkl · ‎02-10-2009

Hi

Whats the config of other router i.e the rip config.

check the below link.

http://www.cisco.com/en/US/tech/tk364/technologies_tech_note09186a0080093fd8.shtml

Thanks

Mahmood

francisco_1 · ‎02-10-2009

r1

interface Loopback0

ip address 192.168.254.1 255.0.0.0

!

interface Serial1/0

ip address 12.0.0.1 255.0.0.0

serial restart-delay 0

router rip

version 1

network 12.0.0.0

network 192.168.254.0

!

r1# sh ip rip database

12.0.0.0/8 auto-summary

12.0.0.0/8 directly connected, Serial1/0

192.0.0.0/8 redistributed

[0] via 0.0.0.0,

r2

interface Loopback0

ip address 10.2.0.2 255.0.0.0

!

interface Serial1/0

ip address 12.0.0.2 255.0.0.0

serial restart-delay 0

!

router rip

version 1

network 10.0.0.0

network 12.0.0.0

!

If i change the mask on r1 loopback0 to classful B/C then r2 will see the 192.168.254.0 as update in it routing table!.

francisco_1 · ‎02-10-2009

the doc is saying if the subnet information part of the same major net as the interface that sources the update is not the same, then Router 1 should summarizes at the major net boundary and advertises the network.

if they are the same, then it check the mask. if the mask are the same, then the network is advertised. if not unless it is a host route /32, then it will drop it.

in the example above 192.168.254.0 and 12.0.0.0 are not part of same major net. rip should summarizes it.

let me know if i'm missing something...

Francisco