Version 7.2 451 Mediant 800B Gateway & E-SBC
User's Manual 20. Coders and Profiles
Parameter Description
attribute, the offerer must not multiplex RTP and RTCP packets. If
both ICE and multiplexed RTP-RTCP are used, the initial SDP offer
must also include the "a=candidate:" attribute for both RTP and RTCP
along with the "a=rtcp:" attribute, indicating a fallback port for RTCP in
case the answerer does not support RTP and RTCP multiplexing.
[0] Not Supported = (Default) RTP and RTCP packets use different
ports.
[1] Supported = Device multiplexes RTP and RTCP packets onto a
single port.
Note: As RTP multiplexing has been defined by the WebRTC
standard as mandatory, the support is important for deployments
implementing WebRTC. For more information on WebRTC, see
WebRTC on page 774.
RTCP Feedback
sbc-rtcp-feedback
[IPProfile_SBCRTCPFeedba
ck]
Enables RTCP-based feedback indication in outgoing SDPs sent to
the SIP entity associated with the IP Profile.
The parameter supports indication of RTCP-based feedback,
according to RFC 5124, during RTP profile negotiation between two
communicating SIP entities. RFC 5124 defines an RTP profile
(S)AVPF for (secure) real-time communications to provide timely
feedback from the receivers to a sender. For more information on RFC
5124, see http://tools.ietf.org/html/rfc5124.
Some SIP entities may require RTP secure-profile feedback
negotiation (AVPF/SAVPF) in the SDP offer/answer exchange, while
other SIP entities may not support it. The device indicates whether or
not feedback is supported on behalf of the SIP entity. It does this by
adding an "F" or removing the "F" from the SDP media line ('m=') for
AVP and SAVP. For example, the following shows "AVP" appended
with an "F", indicating that the SIP entity is capable of receiving
feedback
m=audio 49170 RTP/SAVPF 0 96
[0] Feedback Off = (Default) The device does not send the
feedback flag ("F") in SDP offers/answers that are sent to the SIP
entity. If the SDP 'm=' attribute of an incoming message that is
destined to the SIP entity includes the feedback flag, the device
removes it before sending the message to the SIP entity.
[1] Feedback On = The device includes the feedback flag ("F") in
the SDP offer sent to the SIP entity. The device includes the
feedback flag in the SDP answer sent to the SIP entity only if it was
present in the SDP offer received from the other SIP entity.
[2] As Is = The device does not involve itself in the feedback, but
simply forwards any feedback indication as is.
Note:
As RTCP-based feedback has been defined by the WebRTC
standard as mandatory, the support is important for deployments
implementing WebRTC. For more information on WebRTC, see
WebRTC on page 774.
RTCP-based feedback is required for the VoIPerfect feature (see
VoIPerfect on page 788).
Voice Quality Enhancement
sbc-voice-quality-
enhancement
Enables the device to detect speech and network quality (packet loss
and bandwidth reduction) and triggers the device to overcome
conditions to ensure high call quality.
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