This is just one of the several problems related to mobility (and not only)
that require an approach that is not limited 'by charter' to a specific layer.
I think that it is a positive evolution that standard bodies like IETF, IEEE
and other allow for the best minds to gather, and perform the cross-layer
analysis that is required, as well as suggest solutions that may cross the
traditional layer and standards organization boundaries. We can just hope that
solutions will be found for this kind of cooperation to be enhanced in the
future, whenever needed. The times when the IETF was trying to solve all the
world networking problems at IP layer and higher, while the IEEE was trying to
do the same at link layer and lower are hopefully gone.
Dan
-----Original Message-----
From: Vernon Schryver [mailto:vjs(_at_)calcite(_dot_)rhyolite(_dot_)com]
Sent: 07 August, 2003 1:40 AM
To: ietf(_at_)ietf(_dot_)org
Subject: Re: fixed wireless mesh
From: Iljitsch van Beijnum <iljitsch(_at_)muada(_dot_)com>
xactly what in http://www.ieee802.org/16/docs/03/C80216-03_07.pdf
could possibly be a reasonable topic for the IETF to consider?
I look forward to seeing the IEEE reinvent the network
layer and put it
_below_ the link layer. This should be fun.
How is the IEEE reinventing the network layer this time? They really
have tried in some previous efforts, but I don't see that this time.
ARQ and FEC can be quite desirable in some link layers, particularly
those that would otherwise have error rates higher than the quite
low error rates that TCP readily tolerates.
(What else than a network layer would you call something
that resolves
"end-to-end" addresses into next hop addresses, which is
necessary to
navigate across the mesh.
What end-to-end addresses in the IP sense are you talking about?
This would also need some sort of routing
protocol and a hop limit field.)
I agree they'll need some sort of routing protocol, but despite my
religious affliation with the Churches of RIP and IP, I do not see
that a "hop limit field" is a requirement. They will need to prevent
or deal with loops, but IP-style decrementing TTL or RIP-style
incrementing metric fields are not the only way. For example, perhaps
they could make timestamps work. Or perhaps they can somehow
guarantee
that loops are impossible.
Do you really think that the rest a path through the Internet would
benefit from the route flapping and apparently random decrementing
of the IP TTL field if they were to use the IP TTL field to deal
with loops?
Regardless of the technical issues, do you really think that only the
IETF is allowed to think about routing protocols? It's decades late
to worry about the IEEE crossing the trade union lines by looking at
routing given the existence of link layer routing protocols including
Spanning Tree.
Do you think that the IETF should be in charge of add-drop protocols
for link layers that have those? After all, those protocols involve
addresses and a kind of routing and those link layers often carry IP
packets.
Obviously having wireless mesh nodes route IP would be much
too simple.
That statement is not obvious to me, except in standards committee
turf war terms. My intuition does suggest that none of RIP, IGRP,
EGP, BGP, HELO, or any other IP routing protocol would work well for
what they're trying to do.
Besides, could it be that they want to carry data that don't look
like IP packets? Do you think the IETF should outlaw such heresies?
Vernon Schryver vjs(_at_)rhyolite(_dot_)com