Introduction

When the option "Check availability" is enabled, the PBX will send every 45 seconds a SIP OPTIONS message to the platform. When there is no response from the platform, the PBX will recognise this and knows that this SIP trunk is not available so that a different outgoing trunk can be used if available.

Outgoing message: 2899 2015-02-02 11:44:38.181549 <IP address PBX> <IP address platform> SIP 596 Request: OPTIONS sip:<SIP provider> |

Response: 2900 2015-02-02 11:44:38.199990 <IP address platform> <IP address PBX> SIP 494 Status: 200 Ok |