This article relates to the Cisco TelePresence MCU 4203, Cisco TelePresence MCU MSE 8420, Cisco TelePresence IP VCR 2210, Cisco TelePresence VCR MSE 8220, Cisco TelePresence ISDN GW 3241, Cisco TelePresence ISDN GW MSE 8321, Cisco TelePresence IP GW 3510, Cisco TelePresence MCU 4505 and Cisco TelePresence MCU MSE 8510 products.
Q. Why does my Codian MCU / IP VCR / IP GW become unregistered from an ECS gatekeeper after network problems?
A. If the network connection between the Codian MCU / IP VCR / IP GW and ECS drops for several minutes, ECS sees that the MCU / IP VCR / IP GW is no longer responding to heartbeats, sends an unregister message and removes the MCU / IP VCR / IP GW from its gatekeeper table.
The Codian MC / IP VCR / IP GW does not see this message and believes that its registration to the gatekeeper is still valid. Therefore, the MCU / IP VCR / IP GW does not re-register - but ECS does not route new calls to it.
ECS normally uses the "time to live" setting in registration messages to detect these temporary problems. The gatekeeper lets the registrant know that its registration will only be held for some time, say 5 minutes. The registrant then needs to re-register. Because the registrant regularly re-registers, even if there are network problems, the registration is not lost.
Unfortunately ECS only uses the time to live setting if the registrant includes a time to live in its registration message, and currently the Codian MCU / IP VCR / IP GW does not. This means the Codian MCU / IP VCR / IP GW thinks the registration is permanent and does not re-register after network problems, and its registration can be lost.
One way round this on the MCU is to create a conference on the MCU which repeats daily and is registered with the gatekeeper. That way, whenever this conference becomes active/inactive it will change the MCU's registration with the gatekeeper, thus renewing the registration. There is no equivalent workaround on the IP VCR or IP GW.