Call Survivability - AudioCodes Mediant 800B User Manual

27.9

Call Survivability

This section describes various call survivability features supported by the SBC device.
27.9.1 Auto-Provisioning of Subscriber-Specific Information for
BroadWorks Server for Survivability
This feature enables SBC user registration for interoperability with BroadSoft BroadWorks
server to provide call survivability in case of connectivity failure with the BroadWorks
server, for example, due to a WAN failure. This feature enables local users to dial a local
extension (or any other configured alias) that identifies another local user, in survivability
mode. This feature is enabled using the SBCExtensionsProvisioningMode parameter.
In normal operation, when subscribers (such as IP phones) register to the BroadWorks
server through the device, the device includes the SIP Allow-Events header in the sent
REGISTER message. In response, the BroadWorks server sends the device a SIP 200 OK
containing an XML body with subscriber information such as extension number, phone
number, and URIs (aliases). The device forwards the 200 OK to the subscriber (without the
XML body).
Figure ‎ 2 7-9: Interoperability with BroadWorks Registration Process
The device saves the users in its registration database with their phone numbers and
extensions, enabling future routing to these destinations during survivability mode. When in
survivability mode, the device routes the call to the Contact associated with the dialed
phone number or extension number in the registration database.
Below is an example of an XML body received from the BroadWorks server:
<?xml version="1.0" encoding="utf-8"?>
<BroadsoftDocument version="1.0" content="subscriberData">
<phoneNumbers>
<phoneNumber>2403645317</phoneNumber>
<phoneNumber>4482541321</phoneNumber>
</phoneNumbers>
<aliases>
<alias>sip:bob@broadsoft.com</alias>
<alias>sip:rhughes@broadsoft.com</alias>
</aliases>
<extensions>
<extension>5317</extension>
<extension>1321</extension>
</extensions>
</BroadSoftDocument>
27.9.2 BroadSoft's Shared Phone Line Call Appearance for SBC
Survivability
The device can provide redundancy for BroadSoft's Shared Call Appearance feature.
When the BroadSoft application server switch (AS) fails or does not respond, or when the
network connection between the device and the BroadSoft AS is down, the device
manages the Shared Call Appearance feature for the SIP clients.
User's Manual 444
Mediant 800B GW & E-SBC
Document #: LTRT-10274