[Serusers] busy indicator

[Jiri Kuthan]

At 11:30 AM 5/4/2004, Richard wrote:
>Hi,
>
>In traditional PBX, there is a feature to indicate if
>another user (more precisely his phone) is being used
>or not. This would help before transfering a call.
>
>Is there a way to support this in ser? If record-route
>is used, ser knows that users are on the phone bewteen
>ACK and BYE methods. Is possible somehow tell other
>phones about the status?

No. SER is a proxy server (RFC3261), i.e., it keeps no
call state for scalability reasons. Learning if a phone
is already having conversation would take a B2BUA or
dialog statuus package 
http://www.ietf.org/internet-drafts/draft-ietf-sipping-dialog-package-04.txt
or asking the phone. There may be a feature interaction
with good phones being able to serve multiple calls.

-jiri