Subject: RE: Call for Comments on Issues ID

From: Chip Elliott <[email-masked]>
Date: Wed, 25 Feb 1998 15:37:33 -0500

>Unless you want a massive problem, the only practical approach is that at
>the MANET border (typically part of the conventional network) is a router
>that speaks both conventional tecniques and MANET techniques.

As a practical aside, 'gated' makes it pretty easy to run
different routing protocols on different interfaces, and to share
the resulting reachability/forwarding info. So a MANET/OSPF or
MANET/RIP edge router is not hard to imagine.

I'll say again, though, that the routing issues for transit networks
are harder than those for stub networks. In this go-round of
MANET, we should probably confine ourselves to stub networks.

Note that there's *still* a problem with "on demand" routing
protocols, in that a node X within the ad hoc network will not
be known to the edge router until the edge router needs to
make a path to X. As a result, the edge router will not be
able to advertise any of X's IP addresses until that time,
and so no one outside the ad hoc network will be able
to reach X.

(Or is Mobile IP the solution to this problem? ;-)

More seriously, have we considered exactly how IP addresses
are expected to work in an ad-hoc network? Maybe we have,
and I'm just forgetting....

-- Chip

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From: Dave Johnson <[email-masked]>
Date: Wed, 25 Feb 1998 16:41:44 -0500

>(Or is Mobile IP the solution to this problem? ;-)

Yes!  Of course... at least this is what I think we should do.
The foreign agent, for example, can participate in IP and Mobile IP
as normal, but also participate in the ad hoc routing protocol.

					Dave

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From: Erik Guttman <[email-masked]>
Date: Thu, 26 Feb 1998 07:26:32 +0100 (MET)

> and I'm just forgetting....

Unique numbering, which is used for addressing MANET hosts,
seems to be critical to all the proposals.  When I have asked
in the past, during WG meetings, where these numbers come
from, the answer has been 'they are just there' - perhaps from
a MAC address.  It seems like prenumbering is a requirement for 
any MANET protocol.  Or would dynamic host configuration make 
sense in an ad hoc protocol (MADHCP? Stateless MAADDRCONF?)

Erik

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From: Chip Elliott <[email-masked]>
Date: Thu, 26 Feb 1998 09:08:33 -0500

Let me try to ask my IP-addressing questions a little
more clearly.

1. What is the IP address for the radio interface?

2. Do the nodes have to coordinate the IP network number
   for the shared radio channel, or will each node
   give the channel a different IP network address?

3. Does IP broadcast work on the radio network?
   Specifically, if node A sends a datagram to
   the broadcast address for what IT thinks is the
   IP address of the radio channel, does everyone in
   range get it? Or everyone in the multihop net?
   Will they be surprised to get something with a
   network address that doesn't match their idea of
   the radio channel's network address?

4. Are the radio interface IP addresses private, or
   globally unique? If they're private (not advertised
   outside the node itself), how can one communicate
   with a node that ONLY has a radio interface?
   (Ie, that's the node's only IP address.)
   Or maybe the addresses are known to all nodes
   within the ad hoc network, but not outside the net?

Has anyone thrashed through the answers to these
questions? I apologize if the answer is "yes" and I'm
just being obtuse / forgetful.

Cheers,

-- Chip