AudioCodes Mediant 800B User Manual page 428

Parameter
RTCP Mux
sbc-rtcp-mux
[IPProfile_SBCRTCPMux]
RTCP Feedback
sbc-rtcp-feedback
[IPProfile_SBCRTCPFeedback]
User's Manual
entity, before sending the outgoing SDP offer to the SIP entity.
Note: As the RTCP attribute 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 685.
Enables interworking of multiplexing of RTP and RTCP onto a
single local port, between SIP entities. The parameter enables
multiplexing of RTP and RTCP traffic onto a single local port, for
the SIP entity associated with the IP Profile.
Multiplexing of RTP data packets and RTCP packets onto a single
local UDP port is done for each RTP session (according to RFC
5761). If multiplexing is not enabled, the device uses different (but
adjacent) ports for RTP and RTCP packets.
With the increased use of NAT and firewalls, maintaining multiple
NAT bindings can be costly and also complicate firewall
administration since multiple ports must be opened to allow RTP
traffic. To reduce these costs and session setup times, support for
multiplexing RTP data packets and RTCP packets onto a single
port is advantageous.
For multiplexing, the initial SDP offer must include the "a=rtcp-mux"
attribute to request multiplexing of RTP and RTCP onto a single
port. If the SDP answer wishes to multiplex RTP and RTCP, it must
also include the "a=rtcp-mux" attribute. If the answer does not
include the 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 685.
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
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Mediant 800B Gateway and E- SBC
Description
Document #: LTRT-10296