Subject: discard route, summary of externals and external types

From: "Kostiner, Assaf (Assaf)" <[email-masked]>
Date: Wed, 30 Oct 2002 10:15:18 +0200

Hi,
I wonder if anyone knows:
1. Is the command 'summary-address ip-address mask' for summarization of externals a Cisco proprietary, or do other vendors implement it as well? 
2. Cisco has a command: : [no]discard-route internal / [no] discard-route external - why would anyone want to prevent a discard route from forming?
3. Until now, i have always worked with externals type 2. Is there any good reason to move to type 1? Any special cases?
4. And last... Does anyone knows what opaque LSA is? The RFC which talks about it, doesn't bring detailed examples of using it, only explains the ospf changes.

Thanks for any help, Assaf.

---

From: Acee Lindem <[email-masked]>
Date: Wed, 30 Oct 2002 09:06:38 -0500

Hi Assaf,

Kostiner, Assaf (Assaf) wrote:

> 1. Is the command 'summary-address ip-address mask' for summarization of
> externals a Cisco proprietary, or do other vendors implement it as well?

Many vendors have implemented this command or similar functionality.
Route redistribution has typically been unspecified by the protocols so
every vendors implementation should be considered proprietary.

>
> 2. Cisco has a command: : [no]discard-route internal / [no]
> discard-route external - why would anyone want to prevent a discard
> route from forming?

I'd guess it is to avoid the discard route overlaying a lower priority
(i.e., distance or preference depending on your vendor) route from a
different protocol.

>
> 3. Until now, i have always worked with externals type 2. Is there any
> good reason to move to type 1? Any special cases?

If you want to run OSPF and another protocol (or another instance of OSPF)
and treat the metrics equally.

>
> 4. And last... Does anyone knows what opaque LSA is? The RFC which talks
> about it, doesn't bring detailed examples of using it, only explains the
> ospf changes.

RFC 2370 does describes the protocol mechanisms. Look at
draft-ietf-ospf-hitless-restart-03.txt or
draft-katz-yeung-ospf-traffic-09.txt for examples.

--
Acee