Friday, July 4, 2008

RIPv1 vs RIPv2 Part II

rip weirdness

R1---FR---R2----2.0.0.0/8
| ----R3----|

R1-R2 is 12.0.0.0/8
R1-R3 is 13.0.0.0/8
R2-R3 is 23.0.0.0/8

RIP (default send v1, receive v1,v2) everywhere

R1's route table:

R1#show ip route | begin Gateway
Gateway of last resort is not set

1.0.0.0/16 is subnetted, 1 subnets
C 1.0.0.0 is directly connected, FastEthernet0/0
R 2.0.0.0/8 [120/1] via 13.0.0.3, 00:00:00, Serial1/1
[120/1] via 12.0.0.2, 00:00:00, Serial1/0
R 23.0.0.0/8 [120/1] via 13.0.0.3, 00:00:00, Serial1/1
[120/1] via 12.0.0.2, 00:00:00, Serial1/0
R 10.0.0.0/8 [120/1] via 13.0.0.3, 00:00:00, Serial1/1
[120/1] via 12.0.0.2, 00:00:00, Serial1/0
C 12.0.0.0/8 is directly connected, Serial1/0
C 13.0.0.0/8 is directly connected, Serial1/1
R1#

How could R1 have two equal routes to 2.0.0.0/8?

It should be 1 hop through R2
It should be 2 hops through R3

right?

What do you think?

Well let's do version 2 with no auto-summary:

R1#show ip route | begin Gateway
Gateway of last resort is not set

1.0.0.0/16 is subnetted, 1 subnets
C 1.0.0.0 is directly connected, FastEthernet0/0
R 2.0.0.0/8 [120/1] via 12.0.0.2, 00:00:00, Serial1/0
R 23.0.0.0/8 [120/1] via 13.0.0.3, 00:00:00, Serial1/1
[120/1] via 12.0.0.2, 00:00:00, Serial1/0
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
R 10.3.0.0/16 [120/1] via 13.0.0.3, 00:00:00, Serial1/1
R 10.0.0.0/8 is possibly down,
routing via 12.0.0.2, Serial1/0
C 12.0.0.0/8 is directly connected, Serial1/0
C 13.0.0.0/8 is directly connected, Serial1/1

What is really going on with RIP version 1? I have no idea...if you do, please let me know.

1 comment:

  1. Few people says it is the bug in IOS and few said it did not happen when they had used Real Routers...

    Not sure if your testing is on Real Routers and Correct IOS

    ReplyDelete

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