Subject: RE: Multiple Levels of LMM agents (was: RE: [mobile-ip] Revised L ocalized Mobility Management Requirement s)

From: [email-masked]
Date: Wed, 25 Apr 2001 08:35:45 -0500

> > Ulimately, the issue is one of deployment. The worst possible case
> > is we cycle an LMM protocol without multiple levels of hierarchy
> > to proposed and discover during deployment that we need it. 
> 
> Jim,
> 
> You are stating the design philosophy that leads to kitchen sink
> protocols - put in as much as possible to make sure nothing we can
> ever imagine has been left out.
> 
> I much prefer the opposite philosophy - only include what we know for 
> sure will be needed.
> 
>    Erik

What we do not want to see is another IN (Intelligent network) type of
solution,
and cram a lot of smarts about mobility and optimization in the network by
introducing multiple levels of smart routers/agents. After all "the stupid
network"
does have it's merits :)
There are enough compelling reasons to add one LMM agent, but more than
one ....? Or let's put it this way, how many levels of hierarchy would be
optimal?

So if we were to deploy this solution (since we agree that the issue is one
of 
deployment) today, how would you propose changing existing routers in the
operator's network which may have to become mobility aware? You could
potentially
add one more new router/LMM into the network quite easily as opposed to 
introducing new functionality into an operator's existing network and
equipment.

-Basavaraj

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From: Theo Pagtzis <[email-masked]>
Date: Wed, 25 Apr 2001 10:57:59 -0700

Hi Raj,

> introducing multiple levels of smart routers/agents. After all "the stupid

I do not think that anybody talked about intelligent networks in the
slightest..so I cannot follow your thinking here..

> one ....? Or let's put it this way, how many levels of hierarchy would be

Personally I have provided reasons that are compelling enough to think twice
_before_ trying to even consider droping the proposed requirement.

How many levels of hierarchy would be required at the very least? At least
two...this is "previous and next" this to me is the _fundamental_ notion and
requirement for a multi-level (that is more than _one_) hierarchy.... look all
the MIPv6 scheme that claim speedups...they talk about previous and next...why
can't you think that as a hierarchy...or can you argue that it isn't?

Increasing the cardinality of the depth does not mean that it will grow to
hunderds of hops...do a traceroute from your lab...how many hops do you see
within _your_ admin domain for a route to  London (say). I gather that it is
not more than 4-5 before bordering..

So I think that we are not talking about hierarchies that will grow by the
tenths or hunderds here...

> introducing new functionality into an operator's existing network and

Who said that all routing element have to LMM-aware? I think Phil Roberts
needs to make a serious requirement statement on that here...in the reqs set.

But at the same time who said that a network operator will only buy only a
single LMM-aware router? It is, clearly, a mistake to assume such thing. So
what happens when it has more than one (just say two for the sake of the
argument, although it could be more)...if you want to cater for resiliency to
failures you NEED AT LEAST TWO........so there you have a resiliency fallback
hierarchy,....why is it impossible to see such hierarchy working for other
purposes AS WELL....?????

You may want to pay attentiion to the fact that I said NOTHING about having to
upgrade existing equipment..since you suggest purchasing new equipment (which
I think will be more expensive but nevertheless arguable)

If it scares people to see a multi-level (with an upper boundary of say 4-5)
hierarchy on its own, I would urge people to consider such hierarchy in the
face of resiliency (with a _lower_ boundary of 2)...

Resiliency in the book of LMMs so far IS a requirement...transitively you will
see where I am heading at...

Theo

UCL/ Mobile Systems

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From: Charlie Perkins <[email-masked]>
Date: Wed, 25 Apr 2001 12:57:18 -0700

> one ....? Or let's put it this way, how many levels of hierarchy would be

One thing that the network is supposed to do is route packets.
Everything about this discussion has to do with routing packets.
Thus, comparison to IN is misleading at best.

There is no single answer for the number of levels of hierarchy.
My guess is that at least for now it will be no more than low single digit.
For some installations it will be one.  For some installations
it will be zero.

> introducing new functionality into an operator's existing network and

This really misses the point.  No one is claiming that all installations would
have to have multiple levels of hierarchies.  I only claim that some will, and
that the ones that will want multiple levels will represent many millions (if
not billions) of mobile nodes, in the not-so-distant future.  Furthermore,
the upgrade is not a forklift upgrade.  One can put in regional-aware routers
wherever they are needed, and not disturb the other configuration.

We know that the code to do multiple levels is small, and that the
protocol isn't bad at all.

Regards,
Charlie P.

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From: Behcet Sarikaya <[email-masked]>
Date: Wed, 25 Apr 2001 15:19:52 -0400

Hi Charlie,
  I have a feeling that you are talking about regreg6. Is regreg6 still a
candidate protocol, i.e. after the requirements will the protocol selection
process for LMM  restart?

Charlie Perkins wrote:

>  Furthermore,

Regards,

--
Behcet