Call Forking; Initiating Sip Call Forking; Configuring Sip Forking Initiated By Sip Proxy - AudioCodes E-SBC User Manual

CHAPTER 37 Advanced SBC Features
ISUP data, received in the MIME body of the incoming SIP message is parsed according to the
ISUP variant (SPIROU itu or ansi), indicated in the SIP Content-Type header. The device supports
the following ISUP variants (configured by the 'ISUP Variant' parameter in the IP Profile table):
■ French (France) specification, SPIROU (Système Pour l'Interconnexion des Réseaux
OUverts), which regulates Telecommunication equipment that interconnect with networks in
France. For SPIROU, the device sets the value of the SIP Content-Type header to
"version=spirou; base=itu-t92+".
■ ITU-92, where the device sets the value of the SIP Content-Type header to "version=itu-t92+;
base=itu-t92+".
To configure interworking of SIP and SIP-I endpoints, using the 'ISUP Body Handling' parameter
(IpProfile_SBCISUPBodyHandling) in the IP Profile table (see
You can manipulate ISUP data, by configuring manipulation rules for the SIP Content-Type and
Content-Disposition header values, in the Message Manipulations table (see
Message Manipulation). For a complete description of the ISUP manipulation syntax, refer to the
Syntax for SIP Message Manipulation Reference Guide. In addition, you can use the AudioCodes
proprietary SIP header X-AC-Action in Message Manipulation rules to support the various call
actions (e.g., SIP-I SUS and RES messages) for the ISUP SPIROU variant. For more information,
see Using the Proprietary SIP X-AC-Action

Call Forking

This section describes various Call Forking features supported by the device.

Initiating SIP Call Forking

The SBC device supports call forking of an incoming call to multiple SBC users (destinations). Call
forking is supported by the device's capability of registering multiple SIP client user phone contacts
(mobile and fixed-line extensions) under the same Address of Record (AOR) in its registration
database. This feature can be implemented in the following example scenarios:
■ An enterprise Help Desk, where incoming customer calls are simultaneously sent to multiple
customer service agent extensions.
■ An employee's phone devices, where the incoming call is simultaneously sent to multiple
devices (e.g., to the employee's office phone and mobile SIP phone).
■ An enterprise reception desk, where an incoming call is simultaneously sent to multiple
receptionists.
The device supports various modes of call forking. For example, in Parallel call forking mode, the
device sends the INVITE message simultaneously to all the users registered under the same AOR,
resulting in the ringing of all extensions; the first extension to pick up the call receives the call, and
all other extensions stop ringing. The Call Forking feature is configured by creating a User-type IP
Group and configuring the IP Groups table's parameter, 'SBC Client Forking Mode' (see
Configuring IP
The device can also fork INVITE messages received for a Request-URI of a specific contact
(user), belonging to the destination IP Group User-type, registered in the database to all other users
located under the same AOR as the specific contact. This is configured by the
[SBCSendInviteToAllContacts] parameter.

Configuring SIP Forking Initiated by SIP Proxy

The device can handle the receipt of multiple SIP 18x responses as a result of SIP forking initiated
by a proxy server. This occurs when the device forwards an INVITE, received from a user agent
(UA), to a proxy server and the proxy server then forks the INVITE request to multiple UAs. Several
UAs may answer and the device may therefore, receive several replies (responses) for the single
INVITE request. Each response has a different 'tag' value in the SIP To header.
Groups).
Mediant 1000 Gateway & E-SBC | User's Manual
Configuring IP
Header.
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Profiles).
Configuring SIP