SIP forking enables an extension number to be registered by multiple SIP endpoints (i.e. devices) simultaneously. A single call can ring multiple endpoints at the same time. This makes it possible for your desk phone ring and mobile softphone ring at the same time, and for you enjoy the convenience of taking calls from either device.

SIP Forking can be configured under extension settings. The value of Concurrent Registrations limits how many SIP endpoints the extension can be registered on.


  • The limit of Concurrent Registrations is 4.
  • By default, if one SIP endpoint is busy, other SIP endpoints can still receive calls made to the extension. To restrict other endpoints from receiving calls when the extension is busy, you can enable All Busy Mode for SIP Forking (Settings > PBX > General > SIP > Advanced).