Oracle Communications Session Border Controller — Question 29

You are examining a SIP packet. There is no final response to the ACK method.
What is the reason for this?

Answer options

• A. The ACK method was defined only in RFC 2543 and it has been deprecated.
• B. The ACK method is part of the INVITE transaction.
• C. The ACK method is an exception in RFC 3261.
• D. The ACK method is an optional SIP method.
• E. The ACK method was replaced with the CANCEL method in RFC 3261.

Correct answer: B

Explanation

The correct answer is B because the ACK method is indeed a part of the INVITE transaction and is used to confirm the receipt of a final response. The other options are incorrect as they either misstate the role of the ACK method or its relationship to other methods in the SIP protocol.