A voice engineer is preparing to migrate from PRI to SIP.
Which three SIP request methods are available? (Choose three.)
Click on the arrows to vote for the correct answerA. B. C. D. E. F.
The correct answers to the question are B. PRACK, E. OPTIONS, and F. TRYING.
Here's a brief explanation of each SIP request method:
PRACK (Provisional Acknowledgement): This request method is used to acknowledge the receipt of a provisional response (1xx) to an INVITE request. PRACK is used to confirm that a provisional response was received, even though the final response has not yet been received.
OPTIONS: This request method is used to query a server about its capabilities. The server responds with information about the methods it supports, the codecs it can handle, and other relevant information.
TRYING: This response code is sent by a SIP server to indicate that it has received a request and is processing it. The TRYING response is used to acknowledge receipt of a request and to prevent retransmission of the request.
UNAUTHORIZED, USE PROXY, and NOTIFY are not request methods in SIP. UNAUTHORIZED is a response code used by SIP servers to indicate that authentication is required, USE PROXY is a header field used in SIP messages to indicate that the request should be forwarded to a proxy server, and NOTIFY is a request method used to send asynchronous notifications about the status of a subscription.
In summary, PRACK, OPTIONS, and TRYING are the correct SIP request methods available.