SSCA Session Management 3

Question 1

What does the 'Min-SE' header in SIP Session Timers indicate?

Accepted Answer

The minimum session expiry the UA will accept

Answer

The Min-SE header advertises the minimum value a UA will accept for the Session-Expires interval, preventing excessively short refresh periods.

Question 2

In a SIP call transfer using REFER, what does the Refer-To header contain?

Accepted Answer

The SIP URI of the transfer target

Answer

The Refer-To header in a REFER request contains the SIP URI identifying the target to which the recipient should direct a new request.

Question 3

Which SIP response code indicates that the session description offered in an INVITE is not acceptable?

Accepted Answer

488 Not Acceptable Here

Answer

488 Not Acceptable Here indicates that the session description (SDP) in the request is not acceptable at this time, often due to codec mismatch.

Question 4

What is the purpose of the PRACK method in SIP?

Accepted Answer

To provision reliable transmission of provisional responses (1xx)

Answer

PRACK (Provisional ACKnowledgement) provides reliable delivery of provisional responses when the 100rel option tag is used, as defined in RFC 3262.

Question 5

During early dialog SIP negotiation, which header signals that a UAC requires reliable provisional responses?

Accepted Answer

Require: 100rel

Answer

Including 'Require: 100rel' in an INVITE mandates that the UAS send provisional responses reliably using the PRACK mechanism defined in RFC 3262.

(SSCA) Sip School Certified Associate Practice Test