From: Bernard Omrani (one@xxxxxxxxxxxxxxx)
Date: Fri Apr 27 2001 - 02:55:39 GMT-3
IP classless command is not easy to understand, we know that. But I bet,
after you read the following lines, you will understand what it is all
about.
First, you must understand a very simple logic. Here is the logic:
Me and you are on a journey. If you break my leg, then you must carry me all
the way!
If you understand this logic, you will understand "IP classless".
RIP is telling you: I am classful, if you break my class, then you have to
show me every route there is, or I will drop your package. I will drop it
even though there is a default route (0.0.0.0).
This means, RIP knows about 10.0.0.0
if you break 10.0.0.0 into three, for example to 10.1.0.0 and 10.2.0.0 and
10.3.0.0, and then give RIP a package with a destination of 10.4.0.1, RIP
will drop it. Why? because RIP told you, if you break my class, then you
have to show me every damn route, otherwise I will drop it.
Here, you broke RIP's class so you must show him the way to 10.4.0.1 and
every other 10.x.x.x route in the universe. Otherwise RIP will drop the
package, even if there is default route. RIP will not care about your
default route or last resort route, it will drop your package.
How do you ask RIP not to drop your package and send the unknown
destinations to the default route, although you have been so mean to him and
have broken its class?
you tell him: please, please, ip classless!
Hope this answers your question.
Bernard
-----Original Message-----
From: Jason1 [mailto:jason1@v-labs.net]
Sent: Thursday, April 26, 2001 10:50 AM
To: CCIE_Lab Groupstudy List
Subject: Advance IP Routing - Terry Slattery - IP Classless
I'm looking at pg 99 of Advance IP Routing by Terry Slattery and I felt that
it didn't give a good explaination (and in fact, I felt that it is wrong) of
the "IP Classless" command in the Cisco IOS and also when you should be
using
the command. Any comments from anybody ?
Jason
**Please read:http://www.groupstudy.com/list/posting.html
**Please read:http://www.groupstudy.com/list/posting.html
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 10:29:59 GMT-3