RE:

["Dana L. Blair" <dblair@cisco.com>]

>   -----Original Message-----
>   From: owner-more@ops.ietf.org [mailto:owner-more@ops.ietf.org]On Behalf
>   Of Atsushi Takeshita
>   Sent: Tuesday, July 24, 2001 4:50 PM
>   To: more@psg.com
>   Subject: Re:
>
>
>   Hi.
>
>   I'm reviewing the discussion.
>   Sorry for my non-timely reply.
>
>   >    Session Mobility
>   >    The wireless Internet framework needs to support the ability of the
>   >    user to maintain sessions, including continuity of
>   Internet sessions
>   >    (e.g., http, ssl, tcp, telnet, ftp), during any
>   discontinuity in the
>   >    access network and while changing between terminal devices and/or
>   >    access technologies. For example,
>   >    * the user of a mobile terminal needs to be able to transfer a
>   >    session to a laptop with DSL connection without losing a specific
>   >    session;
>   >    * as a session transfers from an IMT-IS-2000 RAN to an 802.11 LAN
>   >    via handoff from one access network to another, the wireless
>   >    Internet framework needs to support session continuity both within
>   >    the core and in interfaces to other networks.
>   >
>   > DLB:  If using Mobile IP, IP applications are unaware of
>   changes in the
>   > access link.
>
>   Session mobility means the mobility between two (or more)
>   terminals.
>   I don't think Mobile IP can be applied to this.

You'll see later that I ask for a definition of session.

The second example above seems to imply handoff from one
access network to another with the same terminal.  Mobile
IP works for this.

The first example and your definition suggests that a user
is using one terminal
then starts using another terminal and needs some mobility
between the useage of each terminal.  Can you provide
a specific application and usage scenario where this is
important ?

I can think of an example that is solved by
SIP registration:

  User wants to be contacted at terminal A.  Terminal
	sends a SIP register with IP reachability info
	for Terminal A.  User then picks up terminal B
	and wants to be contacted there.  User presses
	button a terminal B which sends a SIP registration
	with reachability info to terminal B.  This registration
	overrides the registration from terminal A.

Is this example appropriate ?
Are there other examples that better describe what session
	mobility requires ?

>
>   >  Accounting
>   >    * on a fixed charge basis, (e.g. fixed charge for an SMS message)
>   >
>   > DLB: I don't understand this.  If I have an always on IP
>   connection that
>   > I am paying for which uses yahoo instant messaging, why does the
>   > service provider need know about this.
>   >
>   > If the service provider, supports an instant messaging service, then
>   > they can bill based on the application accounting info.
>   >
>   >    * on the basis of access to the end service or content (e.g. micro-
>   >    charging)
>   >
>   > DLB:  Not sure I understand this.  Whoever owns the application server
>   > bill for the application usage.  Again if the service
>   provider, provides
>   > applications then they bill for them at the application level.
>
>   I agree with you.
>   The important thing is to keep appropriate application
>   account ing  information which enables various kinds of
>   charging.

Is accounting information for application usage an area that
you think the IETF should consider standardizing ?  I am not
aware of work in the IETF in this area, but I can check if needed.

thanks,
Dana

>
>   ------------------------------------------
>   TAKESHITA, Atsushi
>   DoCoMo Communications Laboratories USA, Inc.
>   takeshita@dcl.docomo-usa.com
>   Tel: 408-451-4705 / Fax: 408-573-1090
>   ------------------------------------------
>
>
>