Configuring Coder Groups; Configuring Allowed Audio Coder Groups - AudioCodes Mediant 1000B User Manual

User's Manual
33

Configuring Coder Groups

33.1

Configuring Allowed Audio Coder Groups

The Allowed Audio Coders Group table lets you configure up to 10 Allowed Audio Coders
Groups. For each Allowed Audio Coders Group, you can configure up to 10 audio coders,
which can include default coders and user-defined (string) coders for non-standard or
unknown coders.
Allowed Audio Coders Groups restrict coders used for SIP entities. Only coders listed in
the Allowed Audio Coders Group (i.e., allowed coders) that is associated with the SIP entity
can be used. If the coders in the SDP offer ('a=rtpmap' field) of the incoming SIP message
are not listed in the Allowed Audio Coders Group, the device rejects the calls, unless
transcoding is configured, whereby extension coders are added to the SDP, as described
in Coder Transcoding on page 599. If the SDP offer contains some coders that are listed in
the Allowed Audio Coders Group, the device manipulates the SDP offer by removing the
coders that are not listed in the Allowed Audio Coders Group, before routing the SIP
message to its destination. Thus, only coders that are common between the coders in the
SDP offer and the coders in the Allowed Audio Coders Group are used. For more
information on coder restriction, see 'Restricting Audio Coders' on page 598.
For example, assume the following:

The SDP offer in the incoming SIP message contains the G.729, G.711, and G.723
coders.

The allowed coders configured for the SIP entity include G.711 and G.729.
The device removes the G.723 coder from the SDP offer, re-orders the coder list so that
G.711 is listed first, and sends the SIP message containing only the G.711 and G.729
coders in the SDP.
To apply an Allowed Audio Coders Group for restricting coders to a SIP entity:
1. Configure an Allowed Audio Coders Group in the Allowed Audio Coders Group table
(see description below).
2. In the IP Profile associated with the SIP entity (see 'Configuring IP Profiles' on page
385):
•
Assign the Allowed Audio Coders Group (using the
IpProfile_SBCAllowedCodersGroupID parameter).
•
Enable the use of Allowed Audio Coder Groups (by configuring the
IpProfile_SBCAllowedCodersMode parameter to Restriction or Restriction and
Preference).
The device also re-orders (prioritizes) the coder list in the SDP according to the order of
appearance of the coders listed in the Allowed Audio Coders Group. The first listed coder
has the highest priority and the last coder has the lowest priority. For more information, see
'Prioritizing Coder List in SDP Offer' on page 603.
Notes:
•
For configuring coders (extension coders) to add to the SDP offer for audio
transcoding, you need to use the Coder Group Settings table (see Configuring
Coder Groups on page 379).
•
The Allowed Audio Coders Group for coder restriction takes precedence over the
Coder Group for extension coders. In other words, if an extension coder is not
listed as an allowed coder, the device does not add the extension coder to the
SDP offer.
Version 7.0 631 Mediant 1000B Gateway and E- SBC
33. Configuring Coder Groups