IP Station Supervision
From Zenitel Wiki
The IP substation is supervised in three different ways.
- Each IP-sub-station has its own unique TCP socket for data communication. This socket send keep-alive frames every 5 second. If no answer, four new attempts are made at one second interval. Thus a broken socket is discovered within 10 seconds and reported as line error from AlphaCom. The keep-alive test is done on the operative system (Linux) level.
- From the Application layer AlphaCom is sending a "PING" approximately every 90 second. The station reply with a "PONG". If one PONG is missing the station is reported as line fault. The purpose of this test is to verify that the application in the IP station is running.
- Group Audio can be transmitted using IP Multicast. See Multicast in AlphaCom for more details. AlphaCom uses a "mping" test to that stations can receive multicasted DIP messages. This test is only done on stations using multicast or relayed multicast for Group Audio. The "mping" message is transmitted the same way as the "agc" group audio message.
The tests above are reported on syslog and the current status is displayed in the AlphaWeb station status list. The tests only supervises DIP connectivity. They do not check that the station can actually receive RTP audio. Usually, if the DIP signaling channel is OK, the audio will also be OK. But a misconfigured firewall may block the RTP audio.
To cover that, the IP station will send a "err rtp" DIP message if a connection or Groupcall is set up, and no RTP audio arrives. This is reported on syslog. This applies both to normal conversations and Group audio functions.
IP station down
IP station down is reported on the log port in the two following ways (Data communication is lost, no PING reply or socket closed):
930: Feb 13 16:17:58 src@Node1 AlphaLog: N001.D065:.Exch:@D65.B25-1 Line Down: IP ST Data Com St 20 "1001 -"
IP station down is also reported to the event handler "faulty station line" ON/OFF.
No license
If a new license key is entered with no IP station licenses or not enough licenses, then some stations will be out of business:
933: Feb 13 16:21:34 src@Node1 AlphaLog: N001.D065:.Exch:@D65.B25-1 Line Down: IP ST License St 20 "1001 -"
The system station will report like ordinary line faults with reference to master board and first port (B25-1) since the IP station is not related to any physical AMC board position.