Subject: Re: router LSA with unknown link type

From: Piotr Galecki <[email-masked]>
Date: Thu, 25 Nov 2004 14:27:13 -0500

Hi Brian,

I would use a common approach in protocol development,
where you are strict in what you send
and liberate in what you accept,
This ensures the best interoperability.

- Piotr

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Date:    Wed, 24 Nov 2004 20:09:35 -0800
From:    Vishwas Manral <[email-masked]>
Subject: Re: router LSA with unknown link type

Hi Acee,

I think we cannot leave this to an implementation, as it can cause routing
loops if different routers have different assumptions and hence different
Router LSA's on which to build the routing table.

Thanks,
Vishwas

---

From: Tony Przygienda <[email-masked]>
Date: Fri, 26 Nov 2004 01:25:18 +0100

> This ensures the best interoperability.

that's just gibberish in the context of this discussion
(unknown link types).  Link-state rouing loop-freeness depends on all people
interpreting the information received the same way and
sometimes there is no 'liberal' way to interpret. Example:

2 routers send 2 instances of the exactly same link, once with a
short, once with a long metric. If they take the 2nd instance
to compute and you take the first, things will loop. If you ignore
both, things may loop. You just don't know what they used to
compute and their computation may influence the traffic they
forward towards you. There is no 'liberal' way here.
Things will not loop only if everyone
interprets such a case in the same way or routers know how
other routers interpret this information (it's much more complex
than that actually but that would only cloud the discussion here).

In  other contextes, the statement makes lots of sense of course

    thanks

    -- tony