AlphaNet Received RTP Supervision

When in conversation with SIP the SIP link from SIPD to the SIP equipment has no "audio path check" frame system during connection. If the SIP device reset or the Ethernet link is lost the call will hang until reset is initiated from AlphaCom side.
If a SIP device has called for instant a door station the call will hang forever....

To avoid this issue a monitoring of received RTP audio is added for AMCD 1043x0521.

Functionality

• Every 10 sec after call connection the number of received RTP frames is compared with the number from last check. If the number is increasing the RX_RTP state is TRUE else it is FALSE.
• When AlphaNet message AUDIO_PATH_CHECK is sent/received (every 30 second) the audio path router is checking the RX_RTP state. (AUDIO_PATH_CHECK is also sent between SIPD and AlphaCom but not sent to the SIP device itself)
• If the RX_RTP state is FALSE during two following checks the link is reset.

The check is preformed in both start and end node in an AlphaNet connection. The check will also cancel AlphaCom to AlphaCom connections if a firewall is blocking the RTP Audio.