Subject: Re: ipv6

From: Sandy Murphy <[email-masked]>
Date: Tue, 15 May 2001 08:27:19 -0400 (EDT)

> If I am not mistaken IPv4 is capable to keep routes up
>until 16 hops of metric and the base of this metric is number of hops. OSPF
>bases the route to follow on speed of links.

(Taking as given and mentioned in later messages that you meant RIP not
IPv4.)

RIP establishes the shortest path to a destination, where the distance
of one hop/link is "1".  OSPF establishes the shortest path to a destination,
where the distance of one link is configurable.  Sometimes, maybe often,
this distance is the delay over the link.  But it does not have to be.
The OSPF link cost is dimensionless.

I suppose that if one could count on OSPF link costs to be a delay
measurement and if the reservation one was trying to make was for a
application that had some desired time properties, it might make a difference
to be running over a network that used OSPF to choose paths than a
network that used RIP to choose paths.  You might be assured of getting
a reservation on a path that had some preferability for your application
over other paths.  But that's not RSVP's business.

And then of course you could only do this inside one autonomous system,
because RIP and OSPF are IGP, or intra-domain, protocols.

--Sandy

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From: Steven Berson <[email-masked]>
Date: Tue, 15 May 2001 09:57:44 -0700 (PDT)

On Tue, 15 May 2001, demir wrote:

> Sandy,
> I don't think it should make any difference on desired properties
> of flows because RSVP reserves the resources according to a flow's needs
> (of course the whole QoS is more than that in Intserv/RSVP). Different
> routes can be chosen by diferent routing protocols when RSVP is used to
> provide/configure resources. RSVP has no control on that. I guess the
> question is "what is the current routing interfaces implemented in RSVP"?
>
> Alper K. Demir

Alper, et al,

I understood Sandy's message to say that OSPF (or other path state
routing algorithms) could potentially use other path characteristics
to route traffic.  These other characteristics could make the RSVP
reservation more likely to succeed, at least intra-domain.

Regards,
Steve

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From: demir <[email-masked]>
Date: Tue, 15 May 2001 09:46:14 -0700 (PDT)

Sandy,

Alper K. Demir

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From: demir <[email-masked]>
Date: Tue, 15 May 2001 12:15:29 -0700 (PDT)

> reservation more likely to succeed, at least intra-domain.

I truly agree with above. However, to me, this is a "QoS
routing" and "traffic management" issue, not RSVP. RSVP gets affected by
it cause it depends on it.

Alper K. Demir