From: adz (ccie1day@totalise.co.uk)
Date: Fri Mar 28 2003 - 06:13:35 GMT-3
Hi,
The OSI protocols is largely used in transmission network management
networks.
It's generally good practice in these large networks to use a system ID that
is the same as the MAC address of an Ethernet port on the device. This is
done because :
1. MAC addresses are unique (?)
2a. the system ID needs to be unique - so why not use the mac address? It's
easy to tell an installer to do this.
You don't know the MAC address until install time, do you can't prepare a
full NSAP for the installer to use.
2b. Using the MAC address is more scalable and inplementable than makeing
something up.
3. the ES-ES protocol which does a similar function to IP's ARP, maps
logical addresses to the datalink layer. With the Ethernet medium, it help
in debugging if the logical address and the L2 address are the same(from a
human perspective). Obviously this only works if there is only one Ethernet
port on the device (normal in OSI Network management networks)
In the LAB, I would be inclined to use a naming scheme that is Quick and
easy for you to implement.
In may well be quicker to use for example xx.xxxx.1111.1111.1111.00 for R1
and xx.xxxx.2222.2222.2222.00 for R2 and so on.
cheers...
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
ccie2be
Sent: 26 March 2003 21:44
To: Group Study
Subject: IS-IS NET clarification
Hi,
I hope this isn't a silly question.
In Doyle's book, he says that usually the NET is made up from the area ID
with
the MAC address appended to it.
I'm wondering is this a rule or a suggestion? And, if it's a rule, does it
matter which MAC address is used?
Since the NET in ISIS is comparable to the Router ID in OSPF and applies to
the router as a whole, it seems to me it shouldn't matter what MAC address
is
used. And, taking that 1 step further, if it doesn't matter what MAC
address
is used, perhaps it doesn't matter if a MAC address is used at all.
Please set me straight on this. Thanks, Jim
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