Three-Way Conferencing - AudioCodes MediaPack MP-124 User Manual

SIP User's Manual
8.2.7.9

Three-Way Conferencing

The device supports three-way conference calls. These conference calls can also occur
simultaneously.
The following example demonstrates three-way conferencing. This example assumes that
a telephone "A" connected to the device wants to establish a three-way conference call
with two remote IP phones "B" and "C":
1. User A has an ongoing call with IP phone B.
2. User A places IP phone B on hold (by pressing the telephone's flash hook button,
defined by the parameter HookFlashCode).
3. User A hears a dial tone, and then makes a call to IP phone C.
4. IP phone C answers the call.
5. User A can now establish a three-way conference call (between A, B and C) by
pressing the flash-hook button, defined by the parameter ConferenceCode (e.g.,
regular flash-hook button or "*1").
Notes:
The device supports the following conference modes (configured by the parameter
3WayConferenceMode):
Conferencing controlled by an external AudioCodes Conference (media) server:
The Conference-initiating INVITE sent by the device uses the ConferenceID
concatenated with a unique identifier as the Request-URI. This same Request-URI is
set as the Refer-To header value in the REFER messages that are sent to the two
remote parties. For this mode, the 3WayConferenceMode parameter is set to 0
(default.)
Conferencing controlled by an external, third-party Conference (media) server:
The Conference-initiating INVITE sent by the device uses only the ConferenceID as
the Request-URI. The Conference server sets the Contact header of the 200 OK
response to the actual unique identifier (Conference URI) to be used by the
participants. This Conference URI is included (by the device) in the Refer-To header
value in the REFER messages sent by the device to the remote parties. The remote
parties join the conference by sending INVITE messages to the Conference server
using this conference URI. For this mode, the 3WayConferenceMode parameter is set
to 1.
Local, on-board conferencing, whereby the conference is established on the device
without the need for an external Conference server. This feature includes local mixing
and transcoding of the 3-Way Call legs on the device, and even allowing multi-codec
conference calls. The device utilizes resources from idle ports to establish the
conference call. The number of simultaneous on-board conferences can be limited
using the parameter MaxInBoardConferenceCalls. In addition, you can designate
ports that can't be used as a resource for conference calls initiated by other ports,
using the parameter 3WayConfNoneAllocateablePorts. Ports that are not configured
with this parameter (and that are idle) are used by the device as a resource for
establishing these type of conference calls. For this mode, the 3WayConferenceMode
parameter is set to 2.
Version 6.2
•
Instead of using the flash-hook button to establish a three-way
conference call, you can dial a user-defined hook-flash code (e.g., "*1"),
configured by the HookFlashCode parameter.
•
Three-way conferencing is applicable only to FXS interfaces.
265
8. IP Telephony Capabilities
February 2011