1. A
302 Moved Temporarily tells the client that the user can be reached at an alternative contact.

2. B
SDP communicates media formats, codecs, and transport details necessary for session negotiation.

3. B
Live call flow demonstrations and captures help adults learn by applying concepts in practice.

4. B
UPDATE modifies session parameters without terminating the session.

5. B
407 Proxy Authentication Required means the client must include credentials in Proxy-Authorization.

6. B
Hands-on SIP troubleshooting labs provide assessments aligned with real-world curriculum goals.

7. C
MESSAGE is the SIP method specifically designed for instant messaging.

8. B
Visual aids such as annotated call-flow diagrams and traces enhance learner understanding.

9. B
Call-ID uniquely identifies SIP dialogs across multiple transactions.

10. B
HIPAA regulations demand secure signaling and media when SIP is used in healthcare.

11. B
Registrar servers maintain user location information for SIP communication.

12. B
Analyzing captured SIP errors builds deeper comprehension of error handling strategies.

13. B
100 Trying indicates the request is received and further processing is in progress.

14. A
A proxy forwards requests, while a redirect server informs the client of new addresses.

15. B
Practical labs with real SIP issues improve retention among adult learners.

16. C
SIP supports UDP and TCP, and may use TLS for security.

17. B
BYE terminates an established SIP session.

18. B
200 OK to INVITE typically contains SDP with negotiated session details.

19. B
Role-play exercises where learners act as SIP entities clarify dialog concepts.

20. A
NAT traversal is managed with STUN, TURN, and ICE extensions.

21. B
The Contact header specifies where a user can be directly reached.

22. A
Digest authentication securely validates clients in SIP.

23. C
SUBSCRIBE allows a client to request event state notifications.

24. B
CANCEL stops a pending INVITE before the session is established.

25. B
Secure RTP (SRTP) ensures that media is encrypted for compliance.

26. C
3xx response codes in SIP signal redirection.

27. B
OPTIONS checks the capabilities of SIP devices or servers.

28. A
Having learners explain call flows strengthens their communication skills.

29. D
Max-Forwards prevents routing loops by limiting the number of hops.

30. B
SIP scalability is achieved with proxies and redirect servers distributing traffic.

31. A
REFER is used for call transfer and conferencing.

32. B
Hands-on labs with error injection best assess SIP troubleshooting ability.

33. A
Encryption of signaling and media is essential for regulatory compliance in finance.

34. A
REGISTER updates the registrar with the client’s current IP and contact information.

35. B
200 OK confirms the call has been answered and the session can begin.

36. B
Delayed troubleshooting labs test whether learners retain SIP skills long term.