Samsung Ubigate iBG2016, Configuration Manual

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CHAPTER 3. SIP Gateway Management
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© SAMSUNG Electronics Co., Ltd.
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Handles the transfer and termination of calls
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SIP supports the transfer of calls from one endpoint to another. During a
call transfer, SIP simply establishes a session between the transferee and
a new endpoint(specified by the transferring party) and terminates the
session between the transferee and the transferring party. At the end of a
call, SIP terminates the sessions among all parties.
SIP Components
SIP is a peer-to-peer protocol. The peers in a session are called user agents.
A user agent can function in one of the following roles:
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User-agent client(UAC)
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A UAC is capable of generating a request based on some external
stimulus(the user clicking a button, or a signal on a PSTN line) and
processing a response.
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User-agent server(UAS)
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A UAS is capable of receiving a request and generating a response
based on user input, external stimulus, the result of a program
execution, or some other mechanism.
Typically, a SIP endpoint is capable of functioning as both a UAC and a UAS, but
functions only as one or the other per transaction. Whether the endpoint functions as
a UAC or a UAS depends on the user agent that initiated the request.
Figure 3.1 Architecture of SIP Network
SIP
RTP
SIP SIP
SIP proxy and
redirect servers
SIP user
Agents(Uas)
SIP gateway
PSTN
Legacy PBX