HP-UX C SIP Stack Programmer's Guide (Novembery 2007)

Working with Register-Clients 129
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WORKING WITH REGISTER-CLIENTS
INTRODUCTION The SIP REGISTER request allows a client to inform a Proxy or redirect server
of the addresses at which the client can be reached.
The Register-Client API of the SIP Stack enables you to register with a Proxy or
a SIP server, refresh registration when needed, and send authentication
information to the server, as required.
The Register-Client API relates to the following two entities:
REGISTER-CLIENT
The register-client (register-client) enables your application to register with
several alternative addresses, each with a unique expiration time, and to refresh
old registrations. A register-client is a stateful object which can assume any state
from a set defined in the Register-Client API. A register-client state represents
the state of the registration process.
REGISTER-CLIENT MANAGER
The Register-Client Manager (Register-ClientMgr) manages the collection of all
register-clients and is mainly used for creating new register-clients. In
applications that register a single user to a particular registrar, all registrations
from the UA should use the same Call-ID value. For this purpose, the Register-
ClientMgr generates and holds the Call-ID that is shared by all register-clients
and is unique to a reboot cycle. The Register-ClientMgr also manages the CSeq-
Step counter, which increases every time the client sends a REGISTER request.