AudioCodes Mediant 4000 SBC User Manual page 538

CHAPTER 22 SBC Overview
■ Avoids interference in SDP negotiation and header manipulation on RTP/SRTP
Direct media is typically implemented for calls between users located in the same LAN or domain,
and where NAT traversal is not required and other media handling features such as media
transcoding is not required. The following figure provides an example of direct media between LAN
IP phones, while SIP signaling continues to traverse the device between LAN IP phones and the
hosted WAN IP-PBX.
➢
To enable direct media:
■ For all calls: Use the global parameter, SBCDirectMedia (overrides all other direct media
configuration).
■ For specific calls:
● SIP Interface: You can enable direct media per SIP Interface (in the SIP Interfaces table),
whereby calls (source and destination) associated with this same SIP Interface are
handled as direct media calls. The SIP Interface can also enable direct media for users
located behind the same NAT. For more information, see
● Direct Media Tag: You can enable direct media between users that are configured with the
same Direct Media tag value. The tag is configured using the IP Profiles table's IPProfile_
SBCDirectMediaTag parameter (see
The device employs direct media between endpoints under the following configuration conditions
(listed in chronological order):
1. Direct media is enabled by the global parameter (SBCDirectMedia).
2. IP Groups of the endpoints are associated with IP Profiles whose 'Direct Media Tag' parameter
has the same value (non-empty value).
3. IP Groups of the endpoints have the 'SBC Operation Mode' parameter set to Microsoft Server
(direct media is required in the Skype for Business environment). For more information, see
Configuring IP
4. IP Groups of the endpoints use the same SIP Interface and the SIP Interface's 'SBC Direct
Media' parameter is set to Enable (SIPInterface_SBCDirectMedia = 1).
Groups.
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Mediant 4000 SBC | User's Manual
Configuring SIP
Configuring IP Profiles).
Interfaces.