AudioCodes Mediant 2000 User Manual page 562

Parameter
Web: Enable History-Info
Header
EMS: Enable History Info
[EnableHistoryInfo]
Web: Use Tgrp
Information
EMS: Use SIP Tgrp
[UseSIPTgrp]
User's Manual
Enables usage of the History-Info header.

[0] Disable (default)

[1] Enable
User Agent Client (UAC) Behavior:

Initial request: The History-Info header is equal to the Request-URI.
If a PSTN Redirect number is received, it is added as an additional
History-Info header with an appropriate reason.

Upon receiving the final failure response, the device copies the
History-Info as is, adds the reason of the failure response to the last
entry, and concatenates a new destination to it (if an additional
request is sent). The order of the reasons is as follows:
a. Q.850 Reason
b. SIP Reason
c. SIP Response code

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 Trunk 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'
562
Description
ISDN Redirecting Reason
Call Forward Universal (CFU)
Call Forward No Answer (CFNA)
Call Forward Busy (CFB)
Document #: LTRT-68822
Mediant 2000