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

132 HP-UX C SIP Stack Programmer’s Guide

CSeq-Step

The CSeq-Step is either managed by the register-client (for stand-alone register-

clients) or by the Register-ClientMgr. Stand-alone register-clients increase the

CSeq-Step for every REGISTER request. Non-stand-alone register-clients

receive the CSeq-Step from the Register-ClientMgr each time they wish to send

a REGISTER Request. The Register-ClientMgr keeps a global CSeq and

increases it each time a new REGISTER request is sent.

You can access the CSeq-Step parameter only with a Get function. The CSeq-

Step parameter is not modifiable.

Call-ID

By default, the register-client gets its Call-ID from the Register-ClientMgr. This

Call-ID is global and generated once when the SIP Stack initializes. Stand-alone

alone register-client or the register-client will generate the Call-ID.

Outbound Address and Local Address

These are the addresses the register-client uses for sending requests. If you set

the register-client outbound address, all requests will be sent to this address

regardless of the message Request-URI. The local address defines the address

from which the Request will be sent (the network card). This is also the address

that will be placed in the top Via header of the Request message. If the local

address is not set, the register-client uses a default local address taken from the

SIP Stack configuration.

Outbound Message

The outbound message is a handle to a message that the register-client will use

for the next outgoing REGISTER request. Before calling an API function that

causes the request to be sent, the application can get the outbound message and

add headers and a body. (Note that at this stage, the object is empty.) You

cannot use the outbound message to set headers that are part of the register-

client transaction key such as To, From, Call-ID, CSeq and Via headers.

Received Message

The last response message that was received by the register-client. You can get

this response only in the context of the register-client state-changed callback

function when the new state indicates that the register-client received a

response.