AudioCodes Mediant 3000 User Manual

Version 7.0 567 Mediant 3000
User's Manual 28. SBC Overview
This DTMF interworking feature is enabled using IP Profiles (ini file parameter IPProfile):

SBCRFC2833Behavior - affects the RFC 2833 SDP offer-answer negotiation:
• [0] (default): the device does not intervene in the RFC 2833 negotiation.
• [1]: each outgoing offer-answer includes RFC 2833 in the offered SDP (the
device adds RFC 2833 only if the incoming offer does not include RFC 2833).
• [2]: the device removes RFC 2833 from the incoming offer.

SBCAlternativeDTMFMethod – the device's first priority for DTMF method at each leg
is RFC 2833. Therefore, if a specific leg negotiates RFC 2833 successfully, then the
chosen DTMF method for this leg is RFC 2833. For legs where RFC 2833 is not
negotiated successfully, the device uses the parameter to determine the DTMF
method for the leg.
The chosen DTMF method determines (for each leg) which DTMF method is used for
sending DTMF’s. If the device interworks between different DTMF methods and one of the
methods is In-band\RFC 2833, detection and generation of DTMF methods requires DSP
allocation.
28.5.9.2 Interworking RTP Redundancy
The device supports interworking of RTP redundancy (according to RFC 2198) between
SIP entities. Employing IP Profiles, you can configure RTP redundancy handling per SIP
entity:

Generate RFC 2198 redundant packets (IpProfile_RTPRedundancyDepth parameter).

Determine RTP redundancy support in the RTP redundancy negotiation in SDP
offer/answer (IpProfile_SBCRTPRedundancyBehavior parameter). If not supported,
the device discards RTP redundancy packets (if present) received from or sent to the
SIP entity.
For more information, see the above parameters in ''Configuring IP Profiles'' on page 391.
28.5.9.3 Interworking RTCP Attribute in SDP
The device supports interworking the RTCP attribute 'a=rtcp' in the SDP between SIP
entities. Employing IP Profiles, you can configure RTCP attribute handling (add, remove or
transparent) per SIP entity, using the IpProfile_SBCSDPHandleRTCPAttribute parameter
(see ''Configuring IP Profiles'' on page 391).
28.5.9.4 Interworking Crypto Lifetime Field
The device supports interworking the lifetime field in the 'a=crypto' attribute of the SDP,
between SIP entities. Employing IP Profiles, you can configure the lifetime field handling
(remove or retain) per SIP entity, using the IpProfile_SBCRemoveCryptoLifetimeInSDP
parameter (see ''Configuring IP Profiles'' on page 391).
28.6 Fax Negotiation and Transcoding
The device can allow fax transmissions to traverse transparently without transcoding or it
can handle the fax as follows:

Allow interoperability between different fax machines, supporting fax transcoding if
required.

Restrict usage of specific fax coders to save bandwidth, enhance performance, or
comply with supported coders. These coders include G.711 (A-Law or Mu-Law), VBD
(G.711 A-Law or G.711 Mu-Law), and T38.

AudioCodes Mediant 3000 Specifications

General

Brand	AudioCodes
Model	Mediant 3000
Category	Gateway
Language	English