Subject: Numbered/unnumbered links

From: Jeff Richards <[email-masked]>
Date: Tue, 16 Apr 2002 07:58:31 -0500

I have a couple of questions that I have not been able to figure out.

1. What are the pros and cons of using numbered or unnumbered
interfaces. Why choose one over the other?

2. I know this next question is not particulally appropriate for this
group, so please forgive me

How is an unnumbered interface assigned to an area?

Thanks in advance for your responses.

Jeff
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Thank you.
Tellabs
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From: Acee Lindem <[email-masked]>
Date: Tue, 16 Apr 2002 09:27:21 -0400

> interfaces. Why choose one over the other?

Jeff,

With respect to unnumbered interfaces:

Pros:
  You don't have to assign an IP address. Another argument I've heard
  is that you don't have the overhead of DNS administration. This
  assumes a policy that all addresses must have DNS names and I
  think it is lame.

Cons:
  You can't directly ping an unnumbered interface. It also won't be
  contained in traceroute output. Your managment tools will
  have to identify it using the ifIndex.

If it were my network I'd use numbered interfaces unless I was
*really* short on addresses.

> How is an unnumbered interface assigned to an area?

This is implementation specific. With our implementation you simply
specify the logical interface name of the unnumbered interface.

router ospf 1
  area 0
   interface unnumbered-POS1
   interface unnumbered-POS2

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>

--
Acee