Subject: RE: [manet] FW: Intended status of produced IDs

From: "Dearlove, Christopher \(UK\)" <[email-masked]>
Date: Tue, 10 Apr 2007 09:02:20 +0100

Charlie has pointed out some issues, and there's history.
But at this point, note that this (two protocols) is what
the WG is chartered to produce.

With regard to one protocol, my view is that such work
would currently be at the pre-experimental stage. Good
for research work (which I would be interested in) but
not for IETF standardisation.

-----Original Message-----
From: Alexandru Petrescu [mailto:[email-masked]] 
Sent: 06 April 2007 09:42
To: Emmanuel Baccelli
Cc: [email-masked]
Subject: Re: [manet] FW: Intended status of produced IDs

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Emmanuel Baccelli wrote:
> Hi Teco,
> SMF is targeted as experimental. OLSRv2 and DYMO are targeted as 
> standards track.

Why two standards track documents?  Why can't it be just one protocol?

Alex

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---

From: "Charles E. Perkins" <[email-masked]>
Date: Tue, 10 Apr 2007 08:46:41 -0700

Hello Chris,

ext Dearlove, Christopher (UK) wrote:
> would currently be at the pre-experimental stage.
What is the difference between experimental and pre-experimental?
>  Good
If a good candidate were put forward, implemented by several
people, and shown to work, then I think it would be suitable for
standardization.  This has not happened yet.

However, there is little doubt that a single protocol would be
better for the user community.  As it is, I think it will be crucial
to have detailed applicability statements in the protocols.  For
instance, as I mentioned in my rushed-through presentation at
the last IETF, the user should be alerted to choose proactive
vs. reactive based on estimates of traffic density, which should
be quantified in the applicabililty statements.

Regards,
Charlie P.

---

From: "Mullen, John" <[email-masked]>
Date: Tue, 10 Apr 2007 10:23:39 -0600

Hi Charles,

I agree, but it seems to me that traffic density, node density,
propagation conditions, etc. can be expected to vary greatly throughout
any practical MANET. For example, a plot of random points distributed
according to a uniform distribution will have local areas of very high
and very low density. If we assume Poisson distributions of traffic
initiation, there will be relatively long gaps during which little
traffic flows and intervals during which several times the average
number of messages are generated.

As a result, I'm not sure that designers can make such choices, except
in very general terms. Putting it another way, I think the descriptions
(and validation) of density, load, etc., would be better stated as
distributions, rather than averages. Otherwise, it may be difficult to
relate these statements to real-world situations.

Bye for now,

John P. Mullen, Ph.D.
(505) 646-2958
[email-masked]
 
-----Original Message-----
From: Charles E. Perkins [mailto:[email-masked]] 
Sent: Tuesday, April 10, 2007 9:47 AM
To: ext Dearlove, Christopher (UK)
Cc: [email-masked]
Subject: Re: [manet] FW: Intended status of produced IDs

Hello Chris,

Regards,
Charlie P.

---

From: "Charles E. Perkins" <[email-masked]>
Date: Tue, 10 Apr 2007 10:53:44 -0700

Hello John,

> number of messages are generated.
This is definitely true.  I translate it to mean that an adaptive 
protocol that
can dynamically determine the best response to the network would be
the best solution, if such a thing existed.

In the meantime, we have to deal with time averaged behaviors.  My
intuition is that the phenomena that vary do not have very much memory
so that variations in time can be smoothly integrated to find a useful
average.
> relate these statements to real-world situations.
Well, I am pretty sure we can make definitive statements of at least
a rudimentary nature, and even offer some quantification.  For instance,
it is clear that if 30% of the nodes in a 100-node network are at all
times communicating with all other nodes, then OLSR is substantially
more efficient.  In fact, at 100 nodes, I think it would be true if only
10% of the nodes were communicating with all other nodes.

We can also make statements about latency.  If we measure that
reactive route discovery takes 200 ms in a certain network, then we
can say that reactive operations are not favored for applications that
require faster launch times.  For instance, if a nuclear power plant
used controls configured as an ad hoc network, I am pretty sure
they would want a proactive routing protocol.  Certain military
layouts are probably more realistic and would similarly need to have
proactive operations.

My belief is that we know enough to make some useful applicability
statements, and that we do need to make them now.  Over time,
we will learn more and be able to make sharper statements.  That
does not mean we are clueless at the current time.

Regards,
Charlie P.

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 16 Apr 2007 17:01:32 +0200

Yes indeed, this is what the Charter says:
> Using mature components from previous work on experimental reactive and
> proactive protocols, the WG will develop two Standards track routing
> protocol specifications:
> 
> - Reactive MANET Protocol (RMP)
> - Proactive MANET Protocol (PMP)
> 
> If significant commonality between RMRP and PMRP protocol modules is
> observed, the WG may decide to go with a converged approach.

Remark the bottom phrase hinting eventually at one converged approach.

> not for IETF standardisation.

I am very surprised it's said so, because I think exactly the opposite: 
all work that is not able to converge and tends to generate two-or-more 
protocols for same task is clearly experimental type, visionary and 
exploratory work, but not 'standard'.  This work is useful but is not 
necessary a standard.  The very meaning (IMHO) of the word standard is 
that there's only one way of doing it.

But again, I understand that some protocol can be used in some context 
only, and with good applicability statements that makes sense.

Alex

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 16 Apr 2007 17:08:16 +0200

Charles E. Perkins wrote:
>> With regard to one protocol, my view is that such work would 
>> currently be at the pre-experimental stage.
>> Good for research work (which I would be interested in) but not for
>>  IETF standardisation.
>> 
> If a good candidate were put forward, implemented by several people, 
> and shown to work, then I think it would be suitable for 
> However, there is little doubt that a single protocol would be better
>  for the user community.  As it is, I think it will be crucial to
> have detailed applicability statements in the protocols.  For
> instance, as I mentioned in my rushed-through presentation at the
> last IETF, the user should be alerted to choose proactive vs.
> reactive based on estimates of traffic density, which should be
> quantified in the applicabililty statements.

I mainly agree.

I think further that each one of the two approaches (re-active and
pro-active) should have its own applicability statement.  The
applicability statement should describe the mobility context into which
that protocol was prototyped.  It should also list one context for which
that protocol was not intended.

This is a useful perspective, better than the universal applicability
perspective.  Especially when not many people consider that a unique
MANET protocol is possible or necessary.

Alex

> 
> Regards, Charlie P.
> 
> 
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