SIP Interoperability and Integration 4

Question 1

Which SIP response code indicates that the called party's endpoint is temporarily unavailable but the request should be retried later?

Accepted Answer

480 Temporarily Unavailable

Answer

480 Temporarily Unavailable means the called UA exists but is not currently reachable, and the caller may retry.

Question 2

In SIP trunking interoperability, Early Media is used to:

Accepted Answer

Carry media before a 200 OK is received, typically for ringback or announcements

Answer

Early Media allows RTP to flow before the 200 OK, enabling ringback tones or announcements during call setup.

Question 3

Which SIP mechanism is used to replace an existing dialog, such as when transferring a call that has already been answered?

Accepted Answer

REFER with Replaces header

Answer

The REFER method with a Replaces header allows a new INVITE to replace an existing confirmed dialog, implementing attended transfer.

Question 4

When a SIP proxy performs Record-Routing, what is the primary reason?

Accepted Answer

To remain in the signaling path for all subsequent requests within the dialog

Answer

Record-Routing ensures the proxy stays in the signaling path for all in-dialog requests such as re-INVITEs and BYEs.

Question 5

For SIP interworking with MGCP-controlled media gateways, which protocol carries the call control signaling to the gateway?

Accepted Answer

MGCP from a Media Gateway Controller

Answer

MGCP (Media Gateway Control Protocol) is used by a Media Gateway Controller (call agent) to control MGCP-based media gateways, while SIP handles the external signaling.

(SIP) Session Initiation Protocol Practice Test

(SIP) Session Initiation Protocol Practice Test

SIP Interoperability and Integration 4