The following table lists the SIP requests.
Table A–1 SIP Request Methods
SIP Request |
Description |
---|---|
INVITE |
A client is being invited to participate in a call. |
ACK |
The client has confirmed the INVITE request. |
BYE |
The call has been terminated by either the caller or callee. |
CANCEL |
Cancel any pending requests. |
OPTIONS |
Queries the server for its capabilities. |
REGISTER |
Registers the client with the server according to the address in the To header. |
PRACK |
Similar to ACK, but a provisional confirmation. |
SUBSCRIBE |
Subscribes the device for an event notification. |
NOTIFY |
Notifies all subscribers of an event. |
PUBLISH |
Publishes an event to a server. |
INFO |
Sends information in the middle of a session that doesn't modify the session's state. |
REFER |
Asks the client to issue a SIP request, typically a call transfer. |
MESSAGE |
Sends an instant message using SIP. |
UPDATE |
Modifies a session's state without altering the dialog state. |
For a list of all SIP requests and links to their definitions in their respective RFCs, see the SIP requests Wikipedia entry.