Detecting the Connection to the IP PBX

The Vocera SIP Telephony Gateway does not have a direct physical connection to the IP PBX (or VoIP gateway). However, some IP PBXs support using the OPTIONS message to ping the PBX to determine if the SIP trunk is up. The following parameters are for sending an OPTIONS message to the IP PBX to determine if the SIP trunk is still alive or not. If the connection goes down (perhaps due to a network problem), an email notification is sent to the Vocera administrator.

Note: If you have set up a VSTG server array and one of the servers stops responding, the Vocera Voice Server automatically redirects outbound calls to another available VSTG server for uninterrupted service. If the connection goes down (perhaps due to a network problem), an email notification is sent to the Vocera administrator.
Table 1. Connection status properties

Property

Description

VTGUseOPTIONSForKeepAlive

Whether to use the OPTIONS message to ping the IP PBX to determine if the SIP trunk is up. The default is TRUE.

Note: You should only set this property to TRUE if your PBX supports using an OPTIONS message as a keep-alive mechanism.

VTGOPTIONSKeepAliveInterval

Specifies the time interval between pings of the IP PBX in seconds. The default is 30, but you can set it as low as 5.

VTGOPTIONSKeepAliveToUser

Specifies the number for the user part of the To header and for the Request URI. The default is "trunk_status". In most cases, you should not change this value. You can specify a null string (""). Do NOT change the default value to a real user number.

VTGUseOPTIONSKeepAliveText

Whether to include the text "keepalive" in the OPTIONS message payload. The default is TRUE, which is appropriate for most IP PBXs.

Note: If you are connecting to a PBX using Dialogic Media Gateway, set this property to FALSE.