» Drag and Drop Questions

By | September 24, 2012

Here you will find answers to CVoice – Drag and Drop Questions

Question 1

The proper call-signaling term to the correct box in the diagram to establish RSVF-based Call Admission Control between the two Cisco Unifield Border Elements: Cisco UBEs. Some option is may be user more than once.

RSVF-based Call Admission.jpg




Here is how the call is established with RSVF-based Call Admission Control

1) The Cisco Unified Communications Manager (at the left-side) sends an H.225 setup to the Cisco UBE.
2) The Cisco UBE processes the call setup information and associates an outbound VoIP dial peer requiring an RSVP reservation. The Cisco UBE sends out an RSVP Reservation request to the remote Cisco UBE.
3) The remote Cisco UBE acknowledges the reservation and initiates the reservation for the return path, which is acknowledged by the local Cisco UBE.
4) The H.225 setup message is routed to the remote Cisco UBE, which then routes the call to the outbound VoIP dial peer pointing to Cisco Unified Communications Manager (at the right-side).
5) H.245 negotiation occurs with media flow-through enabled.
6) The call is established.

Question 2

Click and drag the type of call on the above to the type of voice port it applies to on the below.




1) T1 or E1 with CAS or PRI: PBX to PBX
2) FXO: off-net
3) FXS: local
4) FXS or switch: on-net


First let’s have a quick review of these types of calls:

Local calls are calls that occur when both the calling and called phones are attached to the same router.

On-net calls are calls that need more than one router. For example, the calling phone is from one router and the called phone attaches to another router. But notice that these routers are part of the same network.

Off-net calls are calls that originate on a router but terminate on the PSTN.

PLAR calls occur when a caller picks up a phone and the phone automatically dials a preconfigured number.

PBX to PBX calls are on-net calls, where the source and destination are PBXs.

Next we will explain the answers above:

PBX to PBX connections can use T1 or E1 with CAS or PRI: Nowadays, we often make PBX connections to a network through T1 or E1 lines with channel associated signaling (CAS) or Primary Rate Interface (PRI) signaling.

For off-net calls, the typical connection between the router and the PSTN is through FXO port.

A local call just need FXS ports so it is the only choice for this type of call.

We can make on-net calls through FXS port (phone directly connected to the router) or FXO port (phone connected to a PBX). The “switch” here means that we can connect an IP phone through a switch and place on-net calls through Cisco Unified Communications Manager.

A PLAR call can work with any type of signaling, including E&M, FXO, FXS interfaces.

Question 3

Assume a SIP voice network. Drag each characteristic to the type of SIP call setup the characteristics best describes.




Direct call setup:
+ Nonscalable
+ UA must keep data on large number of destinations
+ Relies on cached information to resolve addresses

Redirect Server Call Setup:
+ Server reports back to a UA with destination coordinates

Proxy Server Call Setup:
+ Most dynamic address resolution capability
+ All setup messages to through server
+ UA incapable of establishing its own sessions

Question 4

Which item correctly describes the relationships between the feature and the category it belongs?

1 Supports analog faxes and modems on a VoIP network
2 Performs call setup and teardown between VoIP networks and the PSTN
3 Interconnects segments of the same or different VoIP networks using different media types
4 Interconnects segments of the same or different VoIP networks using different signaling types

A. Gateway – 1 and 2
CUBE – 3 and 4

B. Gateway – 1 and 3
CUBE – 2 and 4

C. Gateway – 2 and 3
CUBE  – 1 and 4

D. Gateway – 2 and 4
CUBE – 1 and 3

(Note: In the real exam, this question may be represented as a drag and drop question)

Answer: A