System interfaces
35
System functions and features as of R4.1
syd-0570/1.2 – R4.1 – 08.2016
System components
SIP is based on a client-server architecture. Components may include a User Agent,
Registrar Server, Proxy Server and Redirect Server. The three servers are located at
the SIP provider and may be installed on the same system.
Fig. 11 SIP components
• User Agent
User Agents are applications at SIP endpoints, i.e. software or hardware-based
components. The caller is referred to as the User Agent Client; the called party, as
the User Agent Server.
• Registrar Server
An SIP subscriber regularly sends his registration data and his IP address to the
Registrar Server. This information is stored in a database (Location Service).
• Proxy Server
The Proxy Server is responsible for contacts between the subscribers. Following a
request from a User Agent Client, the Proxy Server contacts the Registrar Server to
determine the current IP address of the User Agent Server. It then tries to make
contact with the User Agent Server.
• Redirect Server
The Redirect Server works in a way similar to the Proxy Server. However it hands
over the IP address of the User Agent Server directly to the User Agent Client, who
then takes charge of the connection setup.
SIP provider
Location Service
Registrar server
Proxy server
Redirect server
User Agent
User Agent
To Next Page
Loading...
