RE: [Sip] Re: Callerprefs: Mobility tag

["Drage, Keith (Keith)" <[e-mail]>]

I think I agree with Paul on this one.

Unless someone comes up with a single set of semantics of what it means, it should go away.

What makes it useless is that the explanation below gives two, possibly mutually incompatible, semantics for the same parameter.

I would also point out that the charging characteristics (in Europe) for mobile and fixed line calls are so completely different that it is difficult to conclude on the basis of a single call whether one is cheaper or not. Yes, roaming will maked the roaming user (who could either be calling or called) incur call charges, but the roaming user makes a personal choice to turn their phone on when they are roaming. And the bulk of subscribers making lots of calls are not roaming.

Keith

Keith Drage
Lucent Technologies
Tel: [phone]
Email: [e-mail] 

> -----Original Message-----
> From: Henning Schulzrinne [mailto:[e-mail]]
> Sent: 23 April 2003 02:51
> To: Paul Kyzivat
> Cc: Mary Barnes; Jonathan Rosenberg; '[e-mail]'
> Subject: [Sip] Re: Callerprefs: Mobility tag
> 
> 
> I think this is useful. Yes, having something like "don't call if it 
> costs extra" or "don't call if the person is in a car or 
> meeting" would 
> be better, but until everybody uses RPIDS, 'no mobile phone' 
> is a pretty 
> good approximation and actually implementable. (In European 
> countries, 
> the *caller* pays more for mobile calls, so this is a real 
> concern. And 
> mobile is indeed the distinction that matters, not something else.)
> 
> Paul Kyzivat wrote:
> 
> > I've always had trouble with the semantics of this feature. All the 
> > examples I can think of for using it really depend of coincidental 
> > association between mobility and other features.
> > 
> > For instance, *why* would I prefer to call someone on their 
> fixed phone 
> > rather than their mobile phone?
> > 
> > - because use of the mobile phone is expensive?
> > 
> > - because I know the fixed phone is in a particular location
> >   and I only want to reach them if they are there.
> > 
> > Neither of these are really directly related to the fixed 
> nature of the 
> > phone.
> > 
> > I think I asked Jonathan about this and he felt it should be kept 
> > because it had been around for a long time and we didn't have 
> > justification for removing it. Personally I think it could 
> just go away.
> > 
> >     Paul
> > 
> > Mary Barnes wrote:
> > 
> >> In section 9.9, the mobility tag is described as 
> "indicates whether the
> >> device is fixed, wireless or somewhere in-between", 
> however, there is no
> >> definition for the somewhere in-between. 
> >> So, my initial reaction would be to reword this as 
> "indicates whether the
> >> device is fixed or wireless", but then I got to thinking 
> about what could
> >> have been meant by some in-between and I think there might be some 
> >> value in
> >> defining some of those now. 
> >> One term I had considered was "nomadic" as the 
> "in-between".  But, then I
> >> also got to thinking that perhaps "WiFi" is a good example of the
> >> "in-between".  The usefulness of these really depends upon how they
> >> would/could be used.  The one example I saw in the 
> usecases draft was 
> >> around
> >> wanting to contact someone only on their mobile phone.  
> The inverse of 
> >> this
> >> could be that you absolutely don't want to contact them on 
> their mobile
> >> phone, but would want to contact them on anything else or 
> perhaps only if
> >> they're "fixed" or "WiFi". "Nomadic" might be useful for scenarios 
> >> whereby
> >> one's network connectivity is via tunneling, thus it's 
> indicative not 
> >> being
> >> reachable at the "fixed" device (eg. the hard SIP client), 
> but you are
> >> available on your soft SIP client working from home.   I 
> haven't thought
> >> this all the way through, but I do think additional terms could be 
> >> extremely
> >> useful.
> >>
> >> Mary H. Barnes
> >> [e-mail]
> >>
> >>
> 
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