Using Rfc 4240 - Netann 2-Party Conferencing - AudioCodes Mediant 3000 User Manual

33.2

Using RFC 4240 - NetAnn 2-Party Conferencing

Transcoding bridges (or translates) between two remote network locations, each of which
uses a different coder and/or a different DTMF and fax transport types. The device
supports IP-to-IP transcoding. It creates a transcoding call that is similar to a dial-in, two-
party conference call. The SIP URI in the INVITE message is used as a transcoding
service identifier. The transcoding identifier is configured by the 'Transcoding ID' parameter
(TranscodingID), located in the IP Media Settings page (Configuration tab > VoIP menu >
IP Media > IP Media Settings). For NetAnn transcoding, set the 'Transcoding ID'
parameter to "conf=".
It is assumed that the device is controlled by a third-party, Application server (or any SIP
user agent) that instructs the device to start an IP transcoding call by sending two SIP
INVITE messages with SIP URI that includes the transcoding identifier name. For example:
Invite sip:conf=123@audiocodes.com SIP/2.0
The left part of the SIP URI includes the transcoding ID ('conf=) and is terminated by a
unique number (123). The device immediately sends a 200 OK message in response to
each INVITE.
Each of the transcoding SIP call participants can use a different VoIP coder and a different
DTMF transport type, negotiated with the device using common SIP negotiation.
Sending a BYE request to the device by any of the participants, terminates the SIP session
and removes it from the Transcoding session. The second BYE from the second participant
ends the transcoding session and releases its resources.
The device uses two media (DSP) channels for each call, thereby reducing the number of
available transcoding sessions to 1008. To limit the number of resources for transcoding,
use the 'Number of Media Channels' parameter (MediaChannels), located in the IP Media
Settings page (Configuration tab > VoIP menu > IP Media > IP Media Settings). For
example, if 'Number of Media Channels' is set to "1008", only 504 transcoding sessions are
available.
User's Manual 500
Mediant 3000
Document #: LTRT-89729