router selection

Unanswered Question
Oct 10th, 2007

can some one help me with the following


Suppose a packet destined for enters the router. Which interface will the router send it out





interface e0

interface e1

interface e2

ip route

ip route

ip route

ip route s0

need advise on how to work this sort of questions out.

am sure am overlooking something simple here! i hope!

Thanks in advance.

I have this problem too.
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guruprasadr Wed, 10/10/2007 - 03:26


Before going into the Question, concept is: Router to Route the Packets will always look for a Longest Matched Path exists.

In the above scenario:

ip route s0

Default Route will have administrative distance as "1"

neverthless the longest match for the subnet is: (packet destined for

ip route

In this route atleast the Route get its subnet matched.

So it will be routed this way.


Best Regards,

Guru Prasad R

mundo1234 Wed, 10/10/2007 - 06:01

interesting according the the book i took it from its say e0 interface.

completely confused now!!

can you advise me on how i can work out these sorts of questions.

greatly appreciated.

mark.j.hodge Wed, 10/10/2007 - 06:12

IMHO this is a bogus question, the format of the ip route command is incorrect. It should use prefix masks, but is using wildcard masks. The correct format is in the reference guide :-

Traffic will exit via the interface with the longest match in the routing table, e.g.

destination with routing table e0 e1

matches both interfaces, but e1 is the longer match, and therfore will be used.


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