RE: [RRG] Re: Supposed impossibility of scaling for mobility

[<louise.burness@bt.com>]

Hi
 
  Whilst I agree that if you have a new feature, it will aid deployment, I am very unsure that global mobility is it. I think this because there is a lack of global mobility within the voice world, and I have a suspision that this is partly due to the time to build security associations making handover (as opposed to portability) technically dificult, and partly due to a business model that holds customers to you - the easier you make handover the easier it is for someone to start using a different network
 
What I would really like though is to understand what the trade-offs are - if we support mobility what will it add in terms of system complexity or cost. 
 
and also a better definition of mobility - if we are looking at several seconds, are we really talking "portability" ie no session continuation across the mobility event, even if the IP address stays the same some session types will drop with that type of time lag - I know I hit reload on a web page if it seems sluggish to respond and I suspect I only wait a few seconds; are the mobility events being essentially quite rare (crossing borders) ? The idea of holding your IP address whilst going between home and work raises a load of associated questions about security and accountability. 
 
Also intersting to ask why the phone networks chose to use "nasty routing inefficincies" Also interesting to wonder why, if mobility is that important to you, you dont use existing solutions? 
 
Louise
 

________________________________

From: owner-rrg@psg.com on behalf of William Herrin
Sent: Wed 12/03/2008 21:30
To: Joel M. Halpern
Cc: Routing Research Group
Subject: Re: [RRG] Re: Supposed impossibility of scaling for mobility



On Wed, Mar 12, 2008 at 8:43 AM, Joel M. Halpern <jmh@joelhalpern.com> wrote:
>  1) Solving problems that we don't need to solve is going to weaken a
>  solution.


I'm with Robin on this one. If our solution solves the routing portion
of the mobility problem, it will by its nature solve the multihoming
and system capacity problems as well.

At least as important: the new capability that didn't previously exist
and doesn't otherwise exist will give operators a reason to deploy it
beyond reducing the cost of a DFZ router. Folks aren't real good about
spending more money now in order to spend less later. Damn lousy at it
actually. A valuable new feature like mobility could get us over that
hump.

And for the record, I take my laptop back and forth to work every day.
You probably do too. When I do so, it travels between and through
networks which are administratively and topologically distant. It
would be awfully nice if it could keep its "number" the same way my
cell phone does without the nasty routing inefficiencies that had to
be introduced into the telephone network... Nice enough that I could
see buying service from companies who could do it in preference to
those who couldn't.

As I'm sure you gathered from the above, I'm much more interested in
working on solution trees which also address the routing portion of
the mobility problem than I am in working on solution trees which
don't.

Regards,
Bill Herrin


--
William D. Herrin herrin@dirtside.com bill@herrin.us
3005 Crane Dr. Web: <http://bill.herrin.us/>
Falls Church, VA 22042-3004

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