Specifications

1725-86914-000_C.docx
September 2013 19
Chapter 2: What the Mediant Gateway
Does
In a typical deployment, the Spectralink 84-Series Wireless Handsets use 802.11 a/b/g/n Wi-Fi
with the open-standard Session Initiated Protocol (SIP) for telephony signaling to and from the
call server (i.e. PBX). In a facility where the call server does not recognize the SIP protocol, the
Mediant Gateway provides protocol translation for smooth call operations. The Mediant
Gateway and handsets communicate using SIP and the handsets are configured to register with
the Mediant Gateway . The Mediant Gateway communicates with the PBX via the signaling
protocol supported by the telephony lines.
Fundamentally, the SIP User Agent in the Spectralink 84-Series Wi-Fi handset must register
with a SIP Proxy for operation, and this SIP Proxy must provide routing capability for both
outgoing calls from the handsets as well as incoming calls to them. For this solution, a SIP
Proxy within the Mediant Gateway serves this role. This proxy is a component of a feature
called Standalone Survivability (SAS). The primary application of SAS is to provide routing
capability to SIP handsets that register to a Hosted SIP Proxy when connectivity to that SIP
Proxy becomes unavailable.
In our application of this feature, the Mediant Gateway is configured for continual SAS operation
and the Mediant Gateway permanently operates in Standalone Mode with its local SIP Proxy
enabled.
The Mediant Gateway creates a database of user Registrations as handsets contact the
Mediant Gateway. It uses this database to function as a local SIP Proxy and facilitate user-to-
user calls.
On the other side of the translation, the Mediant Gateway operates as a PRI gateway providing
connectivity to the PBX.
Consequently, configuration options for the SAS component and the PRI component of the
Mediant Gateway must be configured.