Internet Communications Using SIP : Delivering VoIP and Multimedia Services With Session Initiation Protocol {2Nd Ed.}

Figure 12.4 Message waiting notification using SIP events

Writing out in full the first three messages from Figure 12.4 will explain the

use of SIPSUBSCRIBE, 200 OK, and NOTIFY[8] messages. Note the use of the

Secure SIP (sips) URI scheme in this example.

1. Subscriber (Henry’s PC) to Notifier (Henry’s voicemail server) Sub-
   scribe to Henry’s message summary status for one day:
   SUBSCRIBE sips:[email protected] SIP/2.0
   Via: SIP/2.0/TLS 192.0.2.1:5060;branch=z9hG4bK83
   To: <sips:[email protected]>
   From: <sips:[email protected]>;tag=312

1 SUBSCRIBE

Subscribe to mailbox status changes for one day

Immediate synchronization of current state

Notification of new message

Refresh subscription (next day)

Immediate synchronization of current state

Un-subscribe (log out)

Immediate synchronization of current state

(can be ignored by subscriber)

Subscriber Notifier

2 200 OK

7 SUBSCRIBE

8 200 OK

11 (un)SUBSCRIBE

12 200 OK

3 NOTIFY

4 200 OK

9 NOTIFY

10 200 OK

13 NOTIFY

14 200 OK

5 NOTIFY

6 200 OK

218 Chapter 12