SIP MESSAGES

SIP messages are in form of request message (s) and Response message(s) as shown below, these type of messages constitute the SIP Call Flow and has similar translation as the ISUP based message/call flow. The details of each message is not covered in this document.

 

-          SIP request Message

INVITE: To invite someone to a session, Caller requests callee to join a call (e.g. A Sub calls B Sub)

ACK: It is the confirmation of the final response to the INVITE message

CANCEL: It is used to cancel a request before the final response to the request is received.

BYE: It is used to terminate an established call

REGISTER: It is used to register the current location of the subscriber on the register server

OPTIONS: It is used to query the capabilities of the peer device

INFO: It is used to transfer the information exchanged during the call.

MESSAGE: It indicates a message.

SUBSCRIBE: It is used to subscribe to an event notification

NOTIFY: It is used to send an event notification.

UPDATE: It is used to modify attributes of a session before or after the session is established.

REFER: It is used to request the peer device to perform a specified operation.

 

-          SIP response Message

–      1XX  : provisional response//informational (e.g. 100, 180, 181, 182 & 183)

–      2XX  : Successful (e.g. 200 )

–      3XX  : Redirection (e.g. 300, 301)

–      4XX  : Request Failure (e.g. 400, 401, 407 etc.)

–      5XX  : Server Failure

–      6XX  : Global Failure

CALL FLOW:

 

BASIC TEST CASES (Upon successful deployment):

          Test cases

1.       Basic Call Setup (duration check, CLI test, Call clearing tests etc.)

2.       Unsuccessful call set-up

3.       Fax sending (not common)

4.       DTMF

5.       Call Forwarding/Call Waiting

useful document, thanks