From: daneyon hansen (daneyonhansen@xxxxxxxxxxx)
Date: Fri Apr 27 2001 - 17:03:48 GMT-3
I believe your understanding of ip classless is a little off. By
default, a router will make IP forwarding decisions based on the first
few high ordered bits of the first octect in the destination address
within the IP header. ie...01 class A, 10 class B and 110 class C. By
turning on IP classless, your telling the router not to make forwarding
decisions based on the first few bits of the destination address. Your
telling the router to make the longest match when compaing the
destination address of the IP packet to the routing table. So it really
has nothing to do with default routing, IP classless or no IP classless
the router will still route to it's default.
Daneyon
>From: "radha rani" >Reply-To: "radha rani" >To: ccielab@groupstudy.com
>Subject: ip classless >Date: Fri, 27 Apr 2001 10:00:06 -0400 > >I have a
question re: ip classless. My understanding is that if >there is no
>specific route for a subnet in the routing table, this command >allows
the >router to forward packets to unknown destinations using the default
>route. >This being the case when the destination is a subnet of a
network >which is >known to the router. > >My question is : since OSPF is
a classless protocol, why do I need >this >command to have the router
forward packets using the default route. >I see >this all the time where
the router will not utilize the default >route until >this command is
added. > >I can unserstand needing it with IGRP/RIP but why with OSPF? >
>Can someone expalin. Thanks so much.
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