The MPLS WG Archive

[Eric Gray <eric.gray@sandburst.com>]

Lyndon,

    There needs to be a common understanding of what 'node' means
in any specific context.  Node could mean - in this particular context
- the RSVP signaling entity.  In that context, detection of failure of a
control channel is insufficient.

--
Eric Gray

You wrote:

> Hmm, I'm confused here - I did not think the discussion was
> about RSVP Hello's function, it's understood to be detecting
> node failure rather than link or control channel failure.
>
> I thought the question was whether RSVP Hello was necessary if
> you have an alternative way of detecting control channel
> failure, in which case you can tell when there are no control
> channels left standing.  Detection of control channel failure
> could be through LMP Hello or if you have some alternative
> means, like monitoring control channel error rates.
>
> Cheers,
>
> Lyndon
> --
>
> On Wed, 30 May 2001 10:55:39   David Charlap wrote:
> >Dimitrios Pendarakis wrote:
> >>
> >> Could you please clarify why you think RSVP Hello doesn't work for
> >> parallel (redundant) control channels?
> >
> >RSVP Hello messages are sent between adjacent IP addresses.  If there
> >are multiple unnumbered links between two routers, only one set of
> >Hellos are generated for all the links.  If the multiple links are all
> >numbered, then Hello messages are sent for each of the links.
> >
> >As a result of this, RSVP Hello can only detect link failure when all
> >links between two routers are numbered.  If there are unnumbered links
> >between two routers, Hellos will not be interrupted until all of the
> >links fail - meaning it will only detect node failure.
> >
> >-- David
> >
>
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