Configuring General Sbc Settings; Interworking Dialog Information In Sip Notify Messages - AudioCodes Mediant 500L User Manual

User's Manual
33

Configuring General SBC Settings

This section describes configuration of various SBC features.
33.1 Interworking Dialog Information in SIP NOTIFY
Messages
You can enable the device to interwork dialog information (XML body) received in SIP
NOTIFY messages from a remote (WAN) application server. The NOTIFY message is sent
by application servers to notify a SIP client, subscribed to a service and located behind the
device (LAN), of the status of another SIP client in the LAN. For example, user B can
subscribe to an application server for call pick-up service, whereby if user A's phone rings,
the application server notifies user B. User B can then press a pre-configured key
sequence to answer the call.
The NOTIFY message contains the XML body with call identifiers (call-id and tags).
However, as the application server is located in the external network WAN and the SIP
clients behind the device, the call dialog information sent by the application server reflects
only the dialog between the device and itself; not that of the involved SIP clients. This is
due to, for example, the device's topology hiding (e.g., IP address) of its LAN elements.
The device resolves this by replacing the call identifiers received from the application
server with the correct call identifiers (e.g., user A and user B). Thus, users subscribed to
the service can receive relevant NOTIFY messages from the device and use the service.
Figure 33-1: Interworking NOTIFY XML Body for Application Server

To enable the feature:

Configure the 'SBC Dialog-Info Interworking' (EnableSBCDialogInfoInterworking)
parameter to Enable.
When the feature is disabled, the device forwards the NOTIFY message as is, without
modifying its XML body.
Below is an example of an XML body where the call-id, tags, and URIs have been replaced
by the device:
<?xml version="1.0"?>
<dialog-info xmlns="urn:ietf:params:xml:ns:dialog-info"
version="10" state="partial"
entity="sip:alice@example.com">
<dialog id="zxcvbnm3" call-id="67402270@10.132.10.150"
local-tag="1c137249965"
Version 7.2
33. Configuring General SBC Settings
671 Mediant 500L Gateway & E-SBC