From: Scott Morris (swm@emanon.com)
Date: Wed Sep 17 2003 - 00:17:29 GMT-3
The ESI address is simply a UNIQUE address to identify your device on
the ATM network. It really doesn't matter so much how you derive it as
it matters that it is unique. Many people will pick the MAC address
since this is a value that's pre-determined for them in a unique
fashion!
Others will pick the IP address in order to make it more meaningful to
them. However, there's always the possibility with Ips that things
won't be as unique as they should be.
I usually follow a different method than in the Solie book though.
Where each octet I make into a 3-digit number. Your example of
177.10.168.1 I would rewrite as 177.010.168.001.
Then you can break it up quite nicely as 1770.1016.8001 in the ESI
format and read it back just as easily.
Now, you're correct about the ATM switch part. If your switch is
pre-configured with destination esi addresses, then you'll run into some
problems. Most of the time though, that's not the case (in my
experience). 'cause if something is manually expected, then it's not
performing very dynamically! :)
HTH,
Scott
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
ccie2be
Sent: Tuesday, September 16, 2003 10:39 PM
To: Group Study
Subject: ATM - What ESI address to enter?
Hi all,
On page 570, in Practical Studies, it says, "The prefix is obtained
automatically from the immediately attached ATM switch by using ILMI.
Various options are available for the ESI assignment-you can use the MAC
address of one of the attached LAN interfaces of a router, or you can
assign an arbitary address coinciding with the interaface's IP address.
For example, if the IP address of the ATM interfaces (or subinterface)
is 177.10.168.1, you can assign the ESI to be 0177.1016.8100."
A friend says this is wrong and reminds me that Solie's book is full
mistakes. He also told me that he knows that the ESI address entered
must be what the ATM is expecting from first hand experience. He was
doing a practice lab and couldn't establish connectivity until he
entered on the router the specific ESI configured on the directly
attached ATM switch.
I'm hoping someone can settle this and explain why the right answer is
right.
Thanks in advance. dt
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