Subject: (ION) Mobile solution

From: Albert Manfredi <[email-masked]>
Date: Thu, 26 Feb 1998 11:23:24 -0500

I have a proposal for a mobile ATM (or mobile IP?) system that rids
itself of all the kludginess of the current methods. I think you'll
see that it draws on existing concepts. Any comments welcome.

The system is compatible with mobile and geographically fixed
stations. Uses no "home switch" or any such concept. A mobile host
is it own entity, on equal footing with all other stations.

In brief, the system uses TERRESTRIAL links for communications, and
a GEOSYNCHRONOUS satellite net only for the Directory Service. So
delays in the satellite links are easily accommodated. At the same
time, the small number of required satellites guarantees quick
settling of the global directory. And the large bandwidth and short
latency needed for interactive and data transfers are the
responsibility of terrestrial links, i.e. realistic.

1. Each mobile host is assigned a globally unique, flat-space
address. Call this ESI for simplicity (ESI is 6 bytes long, like a
MAC address).

2. When you activate the mobile host, it finds its cell as cell
phones do. The cell provides this host a prefix.

3. Now the mobile host has a complete, hierarchical address so
anyone can place a call to it.

4. When the cell base has assigned the prefix, it simultaneously
transmits to the satellite the prefix+ESI of this new arrival.

5. Calls placed to a mobile host are identified by something in the
number, e.g. AFI (the first byte of the ATM address). But the only
number sent with the request is the globally-unique ESI.

6. The request is routed up to the satellite-based Directory
Service, where the database is searched on the ESI, and the complete
number is returned. If the mobile station is off line, an "off line"
response is provided. And the telephone service _can_, if desired,
take a phone-mail message for that subscriber.

7. From now on, call setup and routing is accomplished as it is for
fixed stations.

8. As the mobile station moves, it will be handed off to a new cell.
This will result in the re-assignment of prefix. Motion vectors can
be used to predict this shift, so the transition to the new link can
be accomplished smoothly.

This is basically ATM or IPV6-style autoconfiguration, with the only
difference being that the time lags in normal autoconfiguration are
not allowable. So the Directory Service must depend on very few
servers, hence the space-based service. This guarantees rapid
synchronization among servers. But the data transfer is always
terrestrial, guaranteeing short delays and more realistic bandwidth
availability.

Temporary non-synchronization of the satellite network is no
problem. At worst, a call is retried. The reason it's no problem is
that the ESI is globally unique. So no one gets a call by mistake.

What do you think? Is this better than mobile IP or mobile ATM or
what?

Thanks.

Bert
[email-masked]
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