Subject: [Manet-dt] RERR propogation

From: Ian Chakeres <[email-masked]>
Date: Sun, 6 Nov 2005 15:43:07 -0800

>From the results presented at IETF 63 we were discussing whether RERR
should be DYMOcast or unicast.  DYMOcast is good because it
disseminates the information to lots of nodes quickly, meanwhile
unicast might reduce the RERR flood significantly.

I'm asking you for your opinion. Should we unicast, dymocast, or
should it depend on something?

Ian Chakeres

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From: "Koojana Kuladinithi" <[email-masked]>
Date: Mon, 7 Nov 2005 16:04:13 +0100

Hi
>disseminates the information to lots of nodes quickly, 
>meanwhile unicast might reduce the RERR flood significantly.

If we use uni-cast RERR, how can we identify nodes that have to be
notified? DYMO does not have a pre-cursor list like in AODV. Or is there
any other way to do this?

>
>I'm asking you for your opinion. Should we unicast, dymocast, 
>or should it depend on something?

That depends on types of networks, networks with higher freq, of
mobility, DYMOcast might be good.

Koojana 

>[email-masked] https://www1.ietf.org/mailman/listinfo/manet-dt
>

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From: Ian Chakeres <[email-masked]>
Date: Mon, 7 Nov 2005 07:27:20 -0800

If RERR were to be unicast, the destination (the source address of the
original data packet that failed to be delivered) would be notified. 
Other sources would be notified if they send data packets along a
broken route.

Can we generalize when to use unicast and when to use DYMOcast?

I think the main issue is the amount of overhead generated in response
to a RERR.  If we use DYMOcast it will likely be much larger than
using unicast.  Using DYMOcast will speed removal of "bad" routes, but
removal of "bad" routes is only important if they are eventually used.
If the route info is never used then the RERR is unneeded overhead.

Ian

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From: Luke Klein-Berndt <[email-masked]>
Date: Mon, 07 Nov 2005 13:39:43 -0500

Should we just add a flag to the routing table that would get checked
if a route has been used? Perhaps it could even be a timer, if we are
going to be using long lived routes. The RERR would only be propagated
by nodes that have used that route recently. I term this "new"
distribution scheme, RelevantCast...

Ian Chakeres wrote:

Ian

Hi

Koojana

Ian Chakeres

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From: Ian Chakeres <[email-masked]>
Date: Mon, 7 Nov 2005 20:55:41 -0800

Is everyone ok with the recommendation that RERR SHOULD only be
propagated if the route has been used? So RERR are still dymocast, but
only nodes with recently used (now broken) routes will actually
propagate the RERR.

Ian Chakeres

On 11/7/05, Luke Klein-Berndt <[email-masked]> wrote:
>  Should we just add a flag to the routing table that would get checked if a
> route has been used? Perhaps it could even be a timer, if we are going to be
> using long lived routes. The RERR would only be propagated by nodes that
> have used that route recently. I term this "new" distribution scheme,
> RelevantCast...
>
>
>  Ian Chakeres wrote:

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From: "Charles E. Perkins" <[email-masked]>
Date: Tue, 08 Nov 2005 01:10:51 -0800

Hello Ian,

This is O.K. with me.

I wonder if it would change the recent results about
the value of path accumulation.

Regards,
Charlie P.

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From: "Pedro M. Ruiz" <[email-masked]>
Date: Tue, 08 Nov 2005 12:17:08 -0800

This is exactly something that I though yesterday. My guess is that it 
would help DYMO with PA improve it performance compared to previous 
results we showed, but we must evaluate how big that improvement is.

In any case, Fran and myself are now working on trying to characterize 
(both analically and through simulation) under which circumstances (# of 
flows, etc.) PA provides advantage.

We'll let you know if we come to a conclusion on this.

--Pedro

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From: "Francisco J. Ros" <[email-masked]>
Date: Wed, 9 Nov 2005 18:57:31 +0100

Hi,

I like this solution. Regarding sequence number length, Charlie's suggestion 
seems really good... it'd be a very flexible approach. I'll try to think a 
bit more about the removal of UERR messages, I'll tell you...

Regards,
fran

On Tuesday 08 November 2005 05:55, Ian Chakeres wrote:
> >  Should we just add a flag to the routing table that would get checked if
> > a route has been used? Perhaps it could even be a timer, if we are going
> > to be using long lived routes. The RERR would only be propagated by nodes
> > that have used that route recently. I term this "new" distribution
> > scheme, RelevantCast...
> >
> >
> >  Ian Chakeres wrote: