Subject: Re: [nemo] moving forward (was: no home network ?)

From: Sandy Murphy <[email-masked]>
Date: Fri, 21 Mar 2003 09:09:11 -0500

>thats right. a PAN connected through a low bandwidth link should
>depend on its HA to manage routes for it. I dont expect the
>mobile router in the PAN to run a routing protocol either.

I'm speaking as a lurker who can't swear to have read the whole thread
here, but I've always been curious about the nested nemo's case.

Is the nesting supposed to be static?  Will there never be the case
that a grandchild net might jump over to become a child in another
nested net?  If that can happen, who handles the revision of routing?
Are you saying that the routing change has to go back to the HA?

Can there ever be the case that a child in one nested net could pass
traffic directly to another child in the same nested net without
going back through the base-wired-landline net?

--Sandy

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From: Michael Thomas <[email-masked]>
Date: Fri, 21 Mar 2003 07:33:05 -0800 (PST)

> Are you saying that the routing change has to go back to the HA?

It certainly seems to me that it *could* be static
as each layer of nesting has no clue about the
other layer -- just like the LMN's don't have any
idea that they are behind a mobile router.

As an aside, this is why I'm dubious about any
kind of artificial edict about the number of
layers... how could you even know if you're
violating it? [*]
 
 > going back through the base-wired-landline net?

As it currently stands, no. This is, of course,
why route optimization would be nice if it could
be engineered...

	  Mike

[*] it seems to me that if we don't limit, we
    need some way to detect topological
    messes for network admins, if not provide some
    BCP kind of advise for how to untangle
    messes...

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From: Alexandru Petrescu<[email-masked]>
Date: Fri, 21 Mar 2003 19:30:23 +0100

Sandy Murphy wrote:
> I'm speaking as a lurker who can't swear to have read the whole 
> thread here, but I've always been curious about the nested nemo's 
> case.

My understanding of nested mobile networks at this point is that there
exist certain configurations of nested mobile networks that work with
the basic-type of NEMO solution (a Mobile IPv6 protocol with the bidir
tunnel, but no ospf or rip).

Of course, there are other nested configurations that are not
supported, and I don't think there is any requirement to try to
support all forms of nested configurations.

> Is the nesting supposed to be static?

I don't think nesting is static, but there are only certain forms of
dynamicity that are supported.  Others are not.

> Will there never be the case that a grandchild net might jump over 
> to become a child in another nested net?

If I'm getting you right, this corresponds to some pictures I drawed
to the list at some point in time.  I could refill space here, if
needed, but otherwise there's an explanation of "cross-over" tunnels
in section B.6 of draft-petrescu-nemo-mrha.

If that kind of configuration corresponds to the model you're
describing, then it is an open question to me whether we're going to
try to support it with a basic solution with Mobile IPv6 (and with no
routing protocol like ospf or rip).

What do you think, are there reasons to try to support this kinds of
configurations (that involve "cross-over" tunnels)?

> If that can happen, who handles the revision of routing? Are you 
> saying that the routing change has to go back to the HA?

If you want, may we try to draw lines and pictures, because I don't
understand if your various mobile networks have the same HA.  How were
those two mobile subnets configured when they were at home?

For example, if the two mobile networks have the same HA, and that
they are peers when they are at home (not aggregated one under the
other), then they can nest one under the other at any time; this will
involve updating the BC of the HA, but will not involve routing table
updates at HA.

> Can there ever be the case that a child in one nested net could 
> pass traffic directly to another child in the same nested net 
> without going back through the base-wired-landline net?

I don't think that the currently thought basic-type of solution looks
into that kind of problem.  At least not from what I've seen until now.

Is this "disconnected operation" problem one of the goals of a
basic-types of solutions?

Alex

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From: William D Ivancic <[email-masked]>
Date: Wed, 26 Mar 2003 13:50:56 -0500

>idea that they are behind a mobile router.

Agreed.  But nesting does not have to be static.  A nemo should be able to 
attach wherever it has permission to.

>why route optimization would be nice if it could

I think a picture from Sandy may clarify the question.  However, as I 
interpret this question,  both children are in the same nested 
network.  Thus, they are on the same LAN.  Therefore, there is no need to 
go home.   If fact, there should be no need to go back home unless you are 
attached to a different mobile router.  A mobile router with multiple LANs 
knows what LANs are attached to it.  Any node attached to that mobile 
router, should be to talk to another node on that router - so long as it 
isn't attached to a nested mobile router.

Will