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Cisco TelePresence IP Gateway Series

MCU/IP VCR/IP GW or Cisco TelePresence Serial Gateway become unregistered from an ECS gatekeeper after network problems

Why does my Cisco TelePresence MCU/IP VCR/IP GW or Cisco TelePresence Serial Gateway become unregistered from an ECS gatekeeper after network problems?

If the network connection between the Cisco TelePresence MCU/IP VCR/IP GW/Serial Gateway and ECS drops for several minutes, ECS sees that the MCU/IP VCR/IP GW/Serial Gateway is no longer responding to heartbeats, sends an unregister message and removes the MCU/IP VCR/IP GW/Serial Gateway from its gatekeeper table.

The Cisco TelePresence MCU/IP VCR/IP GW/Serial Gateway does not see this message and believes that its registration to the gatekeeper is still valid. Therefore, the MCU/IP VCR/IP GW/Serial Gateway 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 Cisco TelePresence MCU/IP VCR/IP GW/Serial Gateway does not. This means the Cisco TelePresence MCU/IP VCR/IP GW/Serial Gateway 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 Cisco TelePresence 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 or Serial Gateway.

This article applies to the following products:

  • Cisco TelePresence IP GW 3500 / MSE IPGW blade
  • Cisco TelePresence IP VCR 2200 / MSE VCR blade
  • Cisco TelePresence ISDN GW 3200 and 3241 / MSE 8310 and 8321 ISDN blades
  • Cisco TelePresence MCU 4200 / MSE 8420
  • Cisco TelePresence MCU 4500
  • Cisco TelePresence MSE 8510 blade
  • Cisco TelePresence Serial GW 3340 / MSE 8330 blade

May 11th, 2012 TAA_KB_91