RE: [More] Session Mobility

[Burke Chris-CCB007 <Chris.Burke@motorola.com>]

There are various ways of implementing mobility.

Consider a cell phone - it has a kind of session mobility in that the route used by the voice traffic virtual circuit changes as the user moves among cell sites. Currently the cell sites are homogeneous but theoretically a mix of different technologies could be used (e.g. GSM and 802.11) and similar hand-off techniques could be employed regardless of the access technology. There's still only one administrative domain ("the carrier") and the entire system looks like "one network". Handoff would be under control of infrastructure equipment, but would require coordinated execution of handoff protocols within the subscriber equipment. This scheme is appealing to some carriers.

One can also, as you suggest, make session mobility the responsibility of the subscriber equipment and design the solution for multiple administrative domains and multiple access technologies using multi-homing etc.

Research effort (and even product development) is ongoing at various companies and universities around both approaches.

Chris

-----Original Message-----
From: amish.chana@orange.co.uk [mailto:amish.chana@orange.co.uk]
Sent: Wednesday, September 19, 2001 2:52 AM
To: more@psg.com
Subject: [More] Session Mobility



Hi,

With reference to the section on session mobility, which requires the ability to
transfer and maintain sessions across different access technologies. What
thoughts do others on this mailing list have with respect to the requirements
and complexity potential solutions may have on the network?
Are these requirements really necessary?
Should session mobility (depending on the type of service) not be the
responsibility of the mobile terminal rather than the network?

IMHO somes of these requirements could be addressed and realised by some of the
work on end-point multi-homing being performed by other WGs. SCTP,
draft-ohta-e2e-multihoming-02.txt and the multi6 WG may offer solutions to the
Session Mobility requirments without requiring the need for additional network
functionality.

As an example, the application sessions mentioned in the draft (http, ssl, tcp,
telnet, ftp) and the ability to transfer them from
a IMT-2000 RAN to a 802.11 LAN or other access technology could be achieved with
 multi-homing. Supporting, session
transfers within the network requires a network element to maintain session
state information. Failure of this element
would impact all currently active sessions. In a multi-homed end-point scenario
the failure of the access network elements
does not impact sessions.


Regards,
Amish




*******************************************************************************
Important. This E-mail is intended for the above named person and may be
confidential and/or legally privileged. If this has come to you in error you
must take no action based on it, nor must you copy or show it to anyone; please
inform the sender immediately.
*******************************************************************************