HP-UX Java SIP Stack Programmer's Guide (February 2008)

ACK Confirms that the client has received a final response to an INVITE
request.
BYE
Indicates to the server that the client wants to release the call.
CANCEL
Cancels a pending user agent client request.
INVITE
Indicates that the user or service is being invited to participate in a session.
OPTIONS
Queries a server with regard to its capabilities.
REGISTER
Registers contact information with a SIP server.
JAIN SIP also supports the following request method name extensions:
INFO
Carries session-related control information that is generated during a
session, as specified in RFC 2976 (The SIP INFO Method).
PRACK Confirms that the client has received a final response to an INVITE.
PRACK is similar to ACK, but specific to the reliability of provisional
responses. The PRACK functionality is defined in RFC 3262 (Reliability
of Provisional Response in the Session Initiation Protocol (SIP)).
UPDATE
Enables a client to update parameters of a session without impacting
the state of a dialog. This functionality is defined in RFC 3311 (The
Session Initiation Protocol (SIP) UPDATE Method).
SUBSCRIBE
Provides an extensible framework by which SIP nodes can request
notification from remote nodes indicating that certain events have
occurred. This functionality is defined in RFC 3265 (Session Initiation
Protocol (SIP) - Specific Event Notification).
NOTIFY
Provides an extensible framework by which SIP nodes can receive
notifications from remote nodes indicating that certain events have
occurred. This functionality is defined in RFC 3265 (Session Initiation
Protocol (SIP) - Specific Event Notification)).
MESSAGE
Used for sending instant messages. This functionality is defined in RFC
3428 (Session Initiation Protocol (SIP) Extension for Instant Messaging).
REFER
Requests that the recipient must refer to a resource provided in the
request. This functionality is defined in RFC 3515 (The Session Initiation
Protocol (SIP) Refer Method).
A Response Message
A response is a message sent by the recipient of a request after it has received and
interpreted the request. A response contains the following information:
Status Code Specifies a 3-digit integer that indicates the result of the response.
Reason phrase Provides a short textual description of the status code.
Headers Specifies the header information.
Message body Contains the actual information sent in the response.
Following is a sample response message:
24 Introduction