The strategy does not scale well to non-directed
pickup. Are you suggesting to register for every phone
wishing to be pickup capable? Are you are assuming
a large memory capacity on each phone to monitor
so many call legs? Forking proxies have
trouble with PSTN gateways. The REGISTER
responses would grow very large with big
pickup groups, not fitting in unfragmented UDP.
The strategy totally breaks for redirect
servers or proxies which don't support
parallel forking.
Other options include ....
1) passing all calls through a B2BUA ahead of time.
Call it a PBX.
2) using a remote control protocol to transfer
the call. The command would
probably come from a centralized server
which the phones trust. See
http://phonectl.sfour.com/
--
Rick
3Com
On Wed, Feb 21, 2001 at 08:39:54AM +0000, James Undery wrote:
>
>
> "Parolkar, Satish" wrote:
>
> > Call Pickup enables a user to answer a ringing station of another user in
> > the pickup group (Centrex Group).
> > I was trying to draw up a message flow to help understand how this feature
> > could be implemented using SIP.
> > Can anyone help me understand how Call Pickup could be implemented using
> > SIP?
> >
>
> Section 4.2.6 of the bis draft describes this facility under the Contact
> header, it is achived through REGISTER.
>
> >
> > Satish Parolkar
> >
> > _______________________________________________
> > Sip-implementors mailing list
> > [EMAIL PROTECTED]
> > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
>
> _______________________________________________
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