SIP Interoperability and Integration 2

Question 1

Which SIP header is used to indicate the protocol version and transport when a request traverses multiple proxies?

Accepted Answer

Via

Answer

Route

Answer

Contact

Answer

Record-Route

Question 2

When integrating SIP with H.323, which gateway function translates between the two signaling protocols?

Accepted Answer

Interworking function (IWF)

Answer

Media gateway controller

Answer

Border element

Answer

Session Border Controller

Question 3

Which IETF RFC defines the SIP-T framework for carrying ISUP information within SIP messages?

Accepted Answer

RFC 3372

Answer

RFC 3261

Answer

RFC 4474

Answer

RFC 3711

Question 4

A SIP UA sends an INVITE to a PSTN gateway that supports only G.711. The UA's SDP offer includes G.729 and G.711. What determines which codec is used?

Accepted Answer

SDP answer from the gateway selects the mutually supported codec

Answer

The UA always wins the codec negotiation

Answer

The gateway selects the first codec in the offer

Answer

RTCP negotiates the codec after the call is established

Question 5

In a SIP-to-WebRTC interworking scenario, which protocol adaptation is typically required for media?

Accepted Answer

RTP to SRTP with DTLS-SRTP keying

Answer

RTP to RTMP

Answer

G.711 to opus transcoding only

Answer

SDP to JSEP conversion only

Question 6

Which SIP mechanism allows a third-party call controller to set up calls between two endpoints without being in the media path?

Accepted Answer

3PCC (Third Party Call Control)

Answer

SIP REFER

Answer

SIP NOTIFY

Answer

SIP UPDATE

Question 7

When a SIP trunk interconnects two enterprises with overlapping private numbering plans, which element typically resolves number translation?

Accepted Answer

Session Border Controller with dial plan translation

Answer

DNS SRV record

Answer

SIP Registrar

Answer

STUN server