AudioCodes Mediant 800B User Manual page 802

Parameter
Web: Use Tgrp Information
EMS: Use SIP Tgrp
CLI: use-tgrp-inf
[UseSIPTgrp]
User's Manual

Upon receiving the final response (success or failure), the device
searches for a Redirect reason in the History-Info (i.e., 3xx/4xx SIP
reason). If found, it is passed to ISDN according to the following
table:
SIP Reason Code
302 - Moved Temporarily
408 - Request Timeout
480 - Temporarily Unavailable
487 - Request Terminated
486 - Busy Here
600 - Busy Everywhere

If history reason is a Q.850 reason, it is translated to the SIP
reason (according to the SIP-ISDN tables) and then to ISDN
Redirect reason according to the table above.
User Agent Server (UAS) Behavior:

The History-Info header is sent only in the final response.

Upon receiving a request with History-Info, the UAS checks the
policy in the request. If a 'session', 'header', or 'history' policy tag is
found, the (final) response is sent without History-Info; otherwise, it
is copied from the request.
Determines whether the SIP 'tgrp' parameter is used. This SIP
parameter specifies the Trunk Group to which the call belongs
(according to RFC 4904). For example, the SIP message below
indicates that the call belongs to Trunk Group ID 1:
INVITE sip::+16305550100;tgrp=1;trunk-
context=example.com@10.1.0.3;user=phone SIP/2.0

[0] Disable = (Default) The 'tgrp' parameter isn't used.

[1] Send Only = The Trunk Group number or name (configured in
the Hunt Group Settings) is added to the 'tgrp' parameter value in
the Contact header of outgoing SIP messages. If a Trunk Group
number / name is not associated with the call, the 'tgrp' parameter
isn't included. If a 'tgrp' value is specified in incoming messages, it
is ignored.

[2] Send and Receive = The functionality of outgoing SIP
messages is identical to the functionality described for option [1]. In
addition, for incoming SIP INVITEs, if the Request-URI includes a
'tgrp' parameter, the device routes the call according to that value (if
possible). The Contact header in the outgoing SIP INVITE (Tel-to-
IP call) contains "tgrp=<source trunk group ID>;trunk-
context=<gateway IP address>". The <source trunk group ID> is
the Trunk Group ID where incoming calls from Tel is received. For
IP-Tel calls, the SIP 200 OK device's response contains
"tgrp=<destination trunk group ID>;trunk-context=<gateway IP
address>". The <destination trunk group ID> is the Trunk Group ID
used for outgoing Tel calls. The <gateway IP address> in "trunk-
context" can be configured using the SIPGatewayName parameter.

[3] Hotline = Interworks the hotline "Off Hook Indicator" parameter
between SIP and ISDN:

For IP-to-ISDN calls:
- The device interworks the SIP tgrp=hotline parameter
(received in INVITE) to ISDN Setup with the Off Hook Indicator
802
Mediant 800B Gateway and E-SBC
Description
ISDN Redirecting Reason
Call Forward Universal (CFU)
Call Forward No Answer (CFNA)
Call Forward Busy (CFB)
Document #: LTRT-10286