User's Manual
Avaya Branch Gateway Manager 10.0 Page 254
15-601011 Issue 29r (Friday, November 02, 2012)B5800 Branch Gateway
· VoIP Silence Suppression: Default = Off
When selected, this option will detect periods of silence on any call over the line and will not send any data during
those silent periods. This feature is not used on IP lines using G.711 between systems. On trunk's between networked
systems, the same setting should be set at both ends.
· Fax Transport Support: Default = Off.
This option is only available if Re-Invite Supported is selected. When enabled, the system performs fax tone
detection on calls routed via the line and, if fax tone is detected, renegotiates the call codec as configured below. The
SIP line provider must support the selected fax method and Re-Invite. The system must have available VCM resources
using an IP500 VCM, IP500 VCM V2 or IP500 Combo base card.
· None
Select this option if fax is not supported by the line provider.
· G.711
G.711 is used for the sending and receiving of faxes.
· T38
T38 is used for the sending and receiving of faxes.
· T38 Fallback
When you enable this option, T38 is used for sending and receiving faxes on a SIP line. If the called destination
does not support T38, the system will send a re-invite to change the transport method to G.711. This option is not
supported by Linux based systems.
· Allow Direct Media Path: Default = On
This settings controls whether IP calls must be routed via the system or can be routed alternately if possible within the
network structure.
· If enabled, IP calls can take routes other than through the system. This removes the need for a voice compression
channel. Both ends of the calls must support Direct Media and be using the same protocol (H.323 or SIP). Enabling
this option may cause some vendors problems with changing the media path mid call.
· If disabled or not supported at on one end of the call, the call is routed via the system. RTP relay support allows
calls between devices using the same audio codec to not require a voice compression channel.
· RE-Invite Supported: Default = Off.
When enabled, Re-Invite can be used during a session to change the characteristics of the session. For example when
the target of an incoming call or a transfer does not support the codec originally negotiated on the trunk. Requires the
ITSP to also support Re-Invite.
· Use Offerer's Preferred Codec: Default = Off.
Normally for SIP calls, the initiator of the calls sends a SIP offer which includes the codecs that they support in order of
preference. The SIP response includes the codec the remote end wants to use for the call. This option can be used to
override that behaviour and use the codec preference offered by the caller. This option is only used when the IP Office
sends INVITES.
· Codec Lockdown: Default = Off.
Supports RFC 3264 Section 10.2 when RE-Invite Supported and Codec Lockdown are enabled. In response to a
SIP offer with a list of codecs supported, some SIP user agents supply a SDP answer that also lists multiple codecs.
This means that the user agent may switch to any of those codecs during the session without further negotiation. The
system does not support multiple concurrent codecs for a session, so loss of speech path will occur if the codec is
changed during the session. If codec lockdown is enabled, when the system receives an SDP answer with more than
one codec from the list of offered codecs, it sends an extra re-INVITE using just a single codec from the list and
resubmits a new SDP offer with just the single chosen codec.