Configure WAN/Provider-Side Gatekeeper Mode Settings

WAN/Provider-Side Gatekeeper Mode

Allows LAN side devices to forward H.323 Remote Access Services (RAS) and Q.931 signaling messages to a WAN gatekeeper for registration and call processing.

Use this mode when designing a centralized gatekeeper solution in which the headquarters location provides the H.323 gatekeeper functionality; all remote locations can deploy the system configured for WAN-side gatekeeper to the headquarters location for call control. H.323 registration and call setup messages are processed by the headquarters gatekeeper, while the RTP media takes the shortest and most direct path between the two WAN-side gatekeeper locations.

WAN/Provider-side GK address

Gatekeeper reachability

Displays whether the gatekeeper specified can be reached.

Registration refresh interval

Enter the registration refresh interval or time to live (TTL) field in the RAS RCF message sent to the LAN side client.

The client sends keepalive registrations to reset the gatekeeper client entry from becoming stale and being deleted from the gatekeeper Clients List. Endpoints typically send a keep-alive registration before this value.

For example, if you enter 30 seconds, most endpoints will send a keep-alive registration at 29 seconds or as early as 19 seconds. The endpoint keepalive registration interval minus the value set in this field can vary depending on the endpoint vendor.

The default value of 0 is used to pass through the original value set from the WAN side gatekeeper. Most WAN side gatekeepers set the TTL field to 300 seconds when deploying the system in WAN-side gatekeeper mode.

Enter the time a client entry is valid on the system.

Each LAN side endpoint has a system client list entry with activity timers to determine if the client is actively sending keepalive registration messages. When a LAN side client fails to update its registration entry on the system within the time specified in this field, the system removes the client from the H.323 Clients List and sends an unregistration request (URQ) to the WAN side gatekeeper.

Listen to multicast messages

Select the Listen to multicast messages checkbox to enable the system LAN side UDP 1718 multicast listener for gatekeeper discovery and registration procedures described in H.225.0.

Enter the port that will be returned in Admission Confirm (ACF) messages. If no Custom Q.931 port is set, the default port of 1720 is used.

Remote NAT devices can intercept H.323 messages and modify these messages which results in call failure. Changing the TCP call setup port to something other than TCP 1720 can help with call completion in these cases. For example, modifying this field to port 5000 modifies the RCF message to instruct the registered WAN side clients to use this port for call signaling. TCP 1720 will still be a system listening port for B2B calls.

Note: Ensure the alternate port is not being used for other services.

Enter the time in seconds between TCP keep-alive messages. If this value is zero, no keep-alive messages are sent.

If no response is received, the TCP stack assumes the connected endpoint is no longer listening, and ends the connection. This field sends TCP keepalives to clients connected to the systems well known TCP 1720 port.

Default is 0 (disabled); the minimum setting is 120 seconds.