3. ____ is the signaling protocol used on SIP trunks to manage VoIP calls.

A. Signaling System 7 (SS7)

B. H.323

C. Integrated Services Digital Network (ISDN)

D. Session Initiation Protocol (SIP)

4. During the Busy Hour of a PBX system, a group of users made and received 15 calls and each call had an average duration (holding time) of 5 minutes. What's the traffic load of this PBX system?

A. 75 Erlangs

B. 15 Erlangs

C. 5 Erlangs

D. 1.25 Erlangs