SSCA Registration Process 2

Question 1

Which SIP header in a REGISTER request identifies the Address-of-Record (AOR) being registered?

Accepted Answer

To

Answer

The To header identifies the AOR — the public address the UA wants to make reachable.

Question 2

What is the purpose of the Contact header in a SIP REGISTER request?

Accepted Answer

To provide the UA's actual device URI for routing incoming calls

Answer

The Contact header carries the device-specific URI (e.g., sip:alice@192.168.1.5:5060) that the registrar will bind to the AOR.

Question 3

Which response code does a SIP registrar return upon successful registration?

Accepted Answer

200 OK

Answer

A 200 OK response confirms the registration was accepted and includes the current binding list in Contact headers.

Question 4

What does the CSeq header contain in a SIP REGISTER request?

Accepted Answer

A session identifier and the method name REGISTER

Answer

CSeq contains a monotonically increasing sequence number followed by the method name, e.g., 'CSeq: 1 REGISTER'.

Question 5

Which header uniquely identifies a SIP registration dialog across all REGISTER transactions from a UA?

Accepted Answer

Call-ID

Answer

Call-ID combined with the From tag uniquely identifies a registration; the registrar uses Call-ID to detect retransmissions.

(SSCA) Sip School Certified Associate Practice Test