SSCA SIP Headers 2

Question 1

Which SIP header is used to indicate the maximum number of times a request can be forwarded by proxies?

Accepted Answer

Max-Forwards

Answer

The Max-Forwards header limits the number of hops a SIP request can traverse, preventing infinite loops.

Question 2

What is the purpose of the Record-Route header in SIP?

Accepted Answer

To record the path taken by a request so proxies remain in the signaling path

Answer

Record-Route is inserted by proxies to ensure they remain in the signaling path for subsequent requests within a dialog.

Question 3

Which header field carries the SIP address of the party sending the request?

Accepted Answer

From

Answer

The From header identifies the logical originator of the request and includes a tag parameter after the dialog is established.

Question 4

What does the Expires header specify in a REGISTER request?

Accepted Answer

The time until the registration binding expires

Answer

The Expires header in a REGISTER request indicates how long the binding between the AOR and Contact URI should remain valid.

Question 5

Which SIP header is used by a UAC to list the supported SIP extensions?

Accepted Answer

Supported

Answer

The Supported header (formerly called Allow-Events in some contexts) lists option tags for extensions the UAC supports but does not require.

(SSCA) Sip School Certified Associate Practice Test