AudioCodes Media 800 MSBR - Page 975

Version 6.6 975 Mediant 800 MSBR
User's Manual 66. Configuration Parameters Reference
Parameter Description

When No Media Anchoring is enabled:

Manipulation is not done on SDP data (offer/answer
transaction) such as ports and IP addresses.

Opening voice channels and allocation of IP media ports are
not required.

Forced Transcoding and Extension Coders features are
disabled for No Media Anchoring calls.

The Coder Restriction feature (Allowed Coders List) operates
simultaneously with No Media Anchoring calls. Restricted
coders are removed from the SDP offer message.
 No Media Anchoring is typically implemented in the following
scenarios:

SBC device is located in the LAN.

Calls between two SIP UAs in the same LAN and signals are
sent to a SIP proxy server that is located in the WAN.

SBC device does not do NAT traversal (for media) and all the
users are in the same domain.
 The benefits of implementing the No Media Anchoring feature
includes the following: saves network bandwidth, reduces CPU
usage (no RTP/SRTP handling), and avoids interference in SDP
negotiation and header manipulation on RTP/SRTP.
 The process for handling the No Media Anchoring feature is as
follows:

Identifying a No Media Anchoring call according to
configuration and the call’s properties (such as source,
destination, IP Group, and SRD).

Handing the identified No Media Anchoring call.
 You can enable No Media Anchoring per SRD (using the
IntraSRDMediaAnchoring parameter), whereby calls between two
UAs that pertain to the same SRD (source and destination) are
handled as a No Media Anchoring (direct media) call.
 Chosen configuration can’t handle call from any UA to a foreign
UA (vice versa) but both UAs belong to the same SRD and the
parameter IntraSRDMediaAnchoring for that specific SRD is > 0.
 When this parameter is disabled, No Media Anchoring calls
between two UAs that belong to separate SRDs cannot be
configured. No Media Anchoring calls between two UAs that
belong to the same SRD is configurable only (in this case).
Web: Transcoding Mode
CLI: transcoding-mode
[TranscodingMode]
Defines the voice transcoding mode (media negotiation) between the
two SBC legs for the SBC application.
 [0] Only if Required = (Default) Do not force transcoding. Many of
the media settings (such as gain control) are not implemented on
the voice stream. The SBC application passes packets RTP to
RTP without any processing.
 [1] Force = Forces transcoding on the outgoing SBC leg. The
device's SBC application interworks the media by implementing
DSP transcoding.
Note: This parameter can also be configured in an IP Profile.
Web: SBC Preferences
Mode
[SBCPreferencesMode]
Determines the order of the Extension coders (coders added if there
are no common coders between SDP offered coders and Allowed
coders) and Allowed coders (defined in the Allowed Coders Group
table) in the outgoing SIP message (in the SDP).

[0] Doesn’t Include Extensions = (Default) Extension coders are