Local Handling Of Sip 3Xx; Interworking Sip Diversion And History-Info Headers - AudioCodes Mediant 1000B User Manual

1. The device receives the Redirect server's SIP 3xx response (e.g., Contact:
<sip:User@IPPBX:5060;transport=tcp;param=a>;q=0.5).
2. The device replaces the Contact header value with the special prefix and database
key value as user part, and with the device's URL as host part (e.g., Contact:
<sip:Prefix_Key_User@SBC:5070;transport=udp>;q=0.5).
3. The device sends this manipulated SIP 3xx response to the Far-End User (FEU).
4. The FEU sends a new request with the Request-URI set to the value of the received
3xx
sip:Prefix_Key_User@SBC:5070;transport=udp).
5. Upon receipt of the new request from the FEU, the device replaces the Request-URI
with
sip:Prefix_User@IPPBX:5070;transport=tcp;param=a).
6. The device removes the user prefix from the Request-URI, and then sends this
Request-URI
sip:User@IPPBX:5070;transport=tcp;param=a).

28.8.1.2 Local Handling of SIP 3xx

The device can handle SIP 3xx responses on behalf of the dialog-initiating UA and retry the
request (e.g., INVITE) using one or more alternative URIs included in the 3xx response.
The new request includes SIP headers from the initial request such as Diversion, History-
Info, P-Asserted-Id, and Priority. The source and destination URIs can be manipulated
using the regular manipulation mechanism.
The device sends the new request to the alternative destination according to the IP-to-IP
Routing table rules. (where the 'Call Trigger' field is set to 3xx). It is also possible to specify
the IP Group that sent the 3xx request as matching criteria for the re-routing rule in this
table ('ReRoute IP Group ID' field).

28.8.2 Interworking SIP Diversion and History-Info Headers

This device can be configured to interwork between the SIP Diversion and History-Info
headers. This is important, for example, to networks that support the Diversion header but
not the History-Info header, or vice versa. Therefore, mapping between these headers is
crucial for preserving the information in the SIP dialog regarding how and why (e.g., call
redirection) the call arrived at a certain SIP UA. If the Diversion header is used, you can
specify the URI type (e.g., "tel:") to use in the header, using the SBCDiversionUriType
parameter.
This feature is configured in the IP Profile table (IPProfile parameter) using the following
parameters:

SBCDiversionMode - defines the device's handling of the Diversion header

SBCHistoryInfoMode - defines the device's handling of the History-Info header
The handling of the SIP Diversion and History-Info headers is described in the table below:
Table 28-1: Handling of SIP Diversion and History-Info Headers
Parameter Value
HistoryInfoMode = Add
DiversionMode = Remove
User's Manual
response's Contact
the new destination
to the
SIP Header Present in Received SIP Message
Diversion
Diversion
converted to
History-Info.
Diversion removed.
502
Mediant 1000B Gateway & SBC
header
address
new destination
History-Info Diversion and History-Info
Not present Diversion removed.
(e.g., RequestURI:
(e.g., RequestURI:
(e.g., RequestURI:
Document #: LTRT-27034