AudioCodes Mediant 4000 SBC User Manual page 429

User's Manual
Parameter
Preferred Ptime
sbc-preferred-ptime
[IpProfile_SBCPreferredPTi
me]
Use Silence Suppression
sbc-use-silence-supp
[IpProfile_SBCUseSilenceSu
pp]
RTP Redundancy Mode
sbc-rtp-red-behav
[IpProfile_SBCRTPRedunda
ncyBehavior]
Version 7.2
is configured for the 'Preferred Ptime' parameter (see below), it is used
as the ptime in the SDP offer.
Defines the packetization time (ptime) in msec for the SIP entity
associated with the IP Profile, in the outgoing SDP offer.
If the 'SDP Ptime Answer' parameter (see above) is configured to
Preferred Value [2] and the 'Preferred Ptime' parameter is configured
to a non-zero value, the configured ptime is used (enabling ptime
transrating if the other side uses a different ptime).
If the 'SDP Ptime Answer' parameter is configured to Remote Answer
[0] or Original Offer [1] and the 'Preferred Ptime' parameter is
configured to a non-zero value, the configured value is used as the
ptime in the SDP offer.
The valid range is 0 to 200. The default is 0 (i.e., a preferred ptime is
not used).
Defines silence suppression support for the SIP entity associated with
the IP Profile

[0] Transparent = (Default) Forward as is.

[1] Add = Enable silence suppression for each relevant coder listed
in the SDP.

[2] Remove = Disable silence suppression for each relevant coder
listed in the SDP.
Note: The parameter requires DSP resources.
Enables interworking RTP redundancy negotiation support between
SIP entities in the SDP offer-answer exchange (according to RFC
2198). The parameter defines the device's handling of RTP
redundancy for the SIP entity associated with the IP Profile. According
to the RTP redundancy SDP offer/answer negotiation, the device uses
or discards the RTP redundancy packets. The parameter enables
asymmetric RTP redundancy, whereby the device can transmit and
receive RTP redundancy packets to and from a specific SIP entity,
while transmitting and receiving regular RTP packets (no redundancy)
for the other SIP entity involved in the voice path.
The device can identify the RTP redundancy payload type in the SDP
for indicating that the RTP packet stream includes redundant packets.
RTP redundancy is indicated in SDP using the "red" coder type, for
example:
a=rtpmap:<payload type> red/8000/1
RTP redundancy is useful when there is packet loss; the missing
information may be reconstructed at the receiver side from the
redundant packets.

[0] As Is = (Default) The device does not interfere in the RTP
redundancy negotiation and forwards the SDP offer/answer
(incoming and outgoing calls) as is without interfering in the RTP
redundancy negotiation.

[1] Enable = The device always adds RTP redundancy capabilities
in the outgoing SDP offer sent to the SIP entity. Whether RTP
redundancy is implemented depends on the subsequent incoming
SDP answer from the SIP entity. The device does not modify the
incoming SDP offer received from the SIP entity, but if RTP
redundancy is required, it will be supported. Select the option if the
429
20. Coders and Profiles
Description
Mediant 4000 SBC