Cell Relay Archive

[albert.e.manfredi@boeing.com]

In article <199802271958.LAA16630@thranduil.trillium.com.trillium.com>,
  rajeev@trillium.com (Rajeev Gupta) wrote:
>
> > The biggest problem with "home server" is that if I am traveling in
> > Keflavik, I sure as hell don't want someone from Helsinki have to call
> > me via a server in Johannesburg. I want to achieve a true mobile
> > capability, where calls are placed as efficiently as stationary unit
> > telephone calls.
>
> This has more to do with the economics of charging and billing
> (particulalry across international boundaries) than technology.
> Certainly the network has the information to route the call efficiently,
> which is fine in a private network. But if you have public networks that
> charge for usage, and the call crosses multiple networks, then every
> operator needs to be compensated.

Let's say I have a mobile phone, I land at the Rome airport, and I call
someone in Rome with my cellular phone. In principle, there should be no
reason why I should have to "belong" to any other service provider, for that
call, than Telecom Italia. And there is so reason why Telecom Italia cannot
identify my source ID (ESI) and send me a bill to whatever home address is
stored in the database. Or, for that matter, to refuse to place the call if
my ESI is in poor standing.

> It is technically possible to route the call without going through the
> home network, but then all transit networks have to establish and
> transact billing information with the home network - again, possible to
> do but potentially expensive to implement.

I think the billing part is not so hard to surmount. But routing the call
without going through the home network is difficult, unless you can use a
scheme such as I suggested (where you have a prefix assigned to you
temporarily as soon as you switch on the mobile phone, and unless the global
directory service can quickly propagate that temporary address of yours).

> Nevertheless, you cannot get around the fact that the home network has
> to be contacted to get the subscriber service and billing data.

I don't think this is so difficult. A global database of all mobile users
ought not be something outrageously intractable these days. A binary search
on a flat address space (the "ESI" address of each mobile phone) should not
be such a difficult task?

> It would not be very scalable to require that all
> networks/switches store the subscriber data for all mobile terminals -
> not to mention the political-ecomonic infeasibility of this in
> international public network scenarios.

I truly wonder. Thinking vagabond-style, there should be no compelling reason
anymore to force people to belong to some "home" network, should there?

> > 1. Dial the unique, flat, address of a mobile unit, from anywhere on the
> > planet (request for mobile location could be identified with an AFI),
>
> Flat addresses are not scalable or routable. You have earlier suggested
> having a permanent prefix -- that makes the address hierarchical and
> assuming that the prefix is routable, no different from a regular
> directory number.

I think you missed the critical point: the ESI is flat and unique, and is
used only to identify your mobile phone gloablly. The _prefix_ is temporary,
and this temporary prefix is used to route calls to you. A permanent prefix
cannot work if you move around. Not if the hierarchical address is to be of
any use.

> Here you gloss over the fact that every terminal (mobile or stationary)
> needs to be connected to a service provider.

Why? Why can't the global mobile database be available to all telcos around
the world?

> Service providers will be very unwilling to
> share their subscriber data with others, without specific bilateral
> arrangements.

Of course, everything would be multilateral.

> In your model, who would own the satellites?

The satellite net already exists, although I don't know that bandwidth is
available and so on. The cost of using it and of maintaining these database
servers around the world would perhaps follow the Intelsat model or such. The
Telcos would all be paid according to how many mobile phones place calls
through them, and they could contribute funds accordingly.

> I think your proposal is not very different from what occurs now
> anyway, except that you want to put location registers in satellites.
> You still have to account for how public networks operate, how charging
> and billing will occur, how subscriber data will be shared, how
> to build large,scalable networks and how to build large, scalable
> databases.

True, but I think it can be done. I think that "mobile" and "static"
telephones should be able to operate almost the same. Placing a call to a
mobile phone should simply require that small first access to the global
mobile phone directory, after which everything procedes as usual.

Bert
manfredi@arl.bna.boeing.com

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