Missed Calls Notification
Presented by...
SIPKnowledge, Inc. 
Motivation:
How many times has it happened to you that your cell phone was either off or in no-reception area/mod; an important call came in, and you wouldn’t even know about it ?! How annoying!
(Remember: currently missed calls notification works only if the missed call(s) arrived when your phone was ON and in a reception area/mod)
Feature:
Under certain conditions, such as No answer or No registration, the SIP network will forward incoming missed calls to a Unified messaging server. Later on when the user shows “signs of life” the Unified messaging server will notify the user for the missed calls.
How this can be accomplished:
The following scheme illustrates how this can be accomplished.

SIPKnowledge, Inc. 
SIPKnowledge pursue research combined with actual product (and standard) work and provide its outcome in a shape of self paced eLearning courses, seminars (on-site training) and actual products. The courses and seminars offer information/self-training on SIP, IP telephony (VoIP) and 3G IMS. Products include:
- Consulting
- SIP/IMS training courses
1. SIP Illustrated - SIP eLearning course
2. 3G IMS Illustrated - 3G IMS eLearning course
- SIP developers aid tools
1. SIP RFC (3261) navigator and clarifier tool
http://www.sipcenter.com/goto/sipcenter-sipknowledge