AudioCodes Mediant 800B User Manual page 864

Parameter
Web: SBC Direct Media
[SBCDirectMedia]
User's Manual

[0] = (Default) Normal processing of REGISTER messages.

[1] = Registration method for BroadWorks server. In a failure
scenario with BroadWorks, the device acts as a backup SIP
proxy server, maintaining call continuity between the enterprise
LAN users (subscribers) and between the subscribers and the
PSTN (if provided).
Note: For a detailed description of this feature, see 'Auto-
Provisioning of Subscriber-Specific Information for BroadWorks
Server' on page 444.
Enables the No Media Anchoring feature (i.e., direct media) for all
SBC calls. No Media Anchoring uses SIP signaling capabilities
without handling the RTP/SRTP (media) flow between remote SIP
user agents (UA). The RTP packets do not traverse the device,
instead, the two SIP UAs establish a direct RTP/SRTP flow between
one another. Signaling continues to traverse the device with minimal
intermediation and involvement to enable certain SBC abilities such
as routing

[0] Disable = (Default) All SRD calls via SBC are not direct
media - internal SRD calls are according to SRD configuration.

[1] Enable = All SBC calls use the No Media Anchoring feature
(i.e., direct media).
Notes:

For more information on No Media Anchoring, see 'No Media
Anchoring (Anti Tromboning)' on page 429.

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)
864
Mediant 800B GW & E-SBC
Description
Document #: LTRT-10274