Subject: Re: (ION) Mobile solution

From: "Greg Zhang" <[email-masked]>
Date: Thu, 5 Mar 1998 15:45:42 -0800

Bert,

I second Pedro's comment that what you are proposing looks very
attractive. Breaking away from "other similar proposals", shedding
its inherent handicaps adds a dimension of freedom that is not otherwise
possible.

>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.

One of most frequently used services in a cellular network is voice mail.
With the new approach, when the called mobile station is off line,  how
does the subscriber profile get retrieved and voice mail taken and stored?
Can this be done on a server (different from the directory server)?

Best regards,

- Greg
____________________________________________________
Greg Zhang    [email-masked]    WACOS, Inc.    (408) 871-3982

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From: Albert Manfredi <[email-masked]>
Date: Fri, 06 Mar 1998 10:10:28 -0500

> Can this be done on a server (different from the directory server)?

Thanks, Greg.

Yes, I've thought about this some, and no doubt other people would
come up with clever solutions. The most realistic solution I can
think of is that the phone mail server is fixed, but an appropriate
one can be chosen by the mobile user at any time.

Here's the scheme.

When someone places a call to a mobile unit, he sends out the flat
ESI field to the Directory Service, expecting back a complete
hierarchical address. Under normal circumstances (no phone mail
service requested), three events can result:

1. The call is placed.

2. The Directory Service has no prefix to assign to that ESI, either
because the old prefix timed out (timing out is absolutely _not_ a
necessity), because the Directory Service was recently down and
rebooted, or because the mobile unit is brand new and has not yet
registered with any local service. This results in a "no link
available" message.

3. The Directory Service does have the prefix assigned to that ESI,
but the mobile unit has since moved on while it was powered down.
Again, you would get this service unavailable indication.

Now, if the mobile user elects to have phone mail service, one
straightforward scheme would be that the Directory Service returns
two numbers when the caller places a call to this mobile ESI. The
first number returned is the prefix to the mobile ESI. The second
number is the prefix of the phone mail server.

Now the caller operates much like a PC with primary and alternate
DNS addresses configured. If the direct number doesn't work, the
call shifts over to the phone mail prefix, with the ESI that goes to
this mobile unit's phone mail.

I'm sure that Grenville could easily come up with a standard message
format to allow mobile units to select mobile servers at any time.
This would be good when traveling, to avoid long distance charges
every time you need to access your phone mail.

Bert
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