Question : Looking for the right format of SIP keepalive message

Hello

There is a VOIP application I write.  I need to send once in a few seconds a SIP message just to check the the other side is available and functioning.

The message can be a dummy one just to let the other side to reply with "OK".

I cannot use the received RTP messages as an indicator.  

Your comments please.

Thanks
Eli

Answer : Looking for the right format of SIP keepalive message

The response you get back will depend on the device that you are pinging. Remember too that even a 481 response tells you that the remote device is listening and responding - you can't really expect much more than that. If the remote device has a problem, then it is unlikely it will be able to tell you.