Exam for Voice over IP (VoIP) Introduction
1. VoIP technologies or methods can be used as a substitute or replacement for which of the following? Select all that apply. a. Transmission facilities b. Switches c. Routers d. Telephones
2.
IP Telephony digitizes the voice, using an analog to digital conversion into a 64 kilobit stream. You may have heard that called____________________ with a standard G.711. a. Packetization b. Pulse Code Modulation c. Time Division Multiplexing d. Statistic Multiplexing
3.
When a vendor talks about compression, they are generally talking about transmission of voice at or below which of the following bit rates: a. 32 kilobits b. 64 kilobits c. 16 kilobits d. 8 kilobits.
4.
In the data world, voice calls or data, are all handled as data in the network. Everything is transmitted in envelopes. Those envelopes are called ___________. Some people call them data-grams. a. Boxes b. Packets c. Channels d. Routes
5.
The envelope consumes bandwidth called overhead in addition to the voice payload. It is not unusual for Voice over IP to use __% of the bandwidth for the voice call and __% of the bandwidth packet overhead. Select the correct proportions. a. 20% and 80% b. 30% and 70% c. 40% and 60% d. 50% and 50%
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6.
CODEC stands for? a. Complex/Decomplex b. Code/Decode c. Coach/Decoach d. Compose/Decompose
7.
Which is a network layer protocol? a. MGCP b. H.323 c. IP d. SIP
8.
The electrical power for LAN Telephones can be provided by: a. External AC adapter b. Power over the LAN via IEEE 802.3af c. Power over the LAN by vendor proprietary methods d. All of the above
9.
Ordinary uncompressed PCM digital voice channel bandwidth is: a. 32 Kilobits per second (Kbps) b. 8 Kbps c. 64 Kbps d. 16 Kbps
10.
What is the main benefit of the silence suppression technique applied in IP Telephony environment? a. It forces the end caller to be silent b. It can reduce the errors in voice transmission c. The bandwidth is compressed d. It reduces the amount of bandwidth required
11.
Select the closest estimate for the percent of installed PBXs (all vendors) that can be IPenabled? a. less than 10% b. over 60% c. over 95% e. less than 40%
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12.
The three different types of IP-PBXs are called: a. IP-enabled, Converged (or Hybrid), and Client/Server b. Voice-Centric, Data-Centric and E-Centric c. Avaya, Nortel, and Cisco d. Small, Medium, and Large
13.
The H.323 standard for signaling uses the following for call set-up: a. E911 b. 802.11 c. H.248 d. Q.931
14.
The function in the H.323 architecture that performs call control, routing and PBX-like capabilities is called the: a. MCU b. Gatekeeper c. Terminal d. Gateway
15.
The function in H.323 that connects packet-based IP networks to circuit-switched networks and telephones is called the: a. MCU b. Gatekeeper c. Terminal d. Gateway
16.
Variations in the delay of packets sent over an IP network are called: a. Jitter b. Compression c. Echo d. Buffer
17.
Which of the following contains all the elements required for any legacy PBX or voice switch? a. T1s and PRIs and Phones b. Computer (Stored Program Control) and Switch Matrix c. Line Cards and Trunk Cards d. Computer, Switch Matrix, Line and Trunk Cards
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18.
The part of the voice packet that contains routing and control information is called the: a. Codec b. Link c. Header d. Payload
19.
Which of the following does not apply to packet switching? a. Uses statistical multiplexing b. Constant, short delay between routers c. No guaranteed bandwidth d. Bandwidth assigned when packet is produced
20.
An important VoIP management goal is restoring service quickly when there are failures. A typical software reboot time for a router is: a. 6 milliseconds b. 6 seconds c. 6 minutes d. 60 minutes
21.
The following are a list of VoIP Management goals. Select the goal that is not on the IT Manager’s list. a. Provide high reliability b. Produce toll quality voice calls c. Diagnose to prevent recurring problems d. Maintain privacy and security e. Eliminate the need to check backup systems
22.
VoIP uses two transport protocols. TCP offers guaranteed delivery, error detection/correction, and retransmission. UDP does not. In H.323 the: a. Talk path (or voice bearer content) uses TCP and signaling uses UDP b. Talk and signaling paths use TCP c. Talk and signaling paths use UDP d. Talk path uses UDP and signaling path uses TCP
23.
Real Time Protocol (RTC) provides what function for the packets? a. Quality of Service monitoring b. Includes time stamping c. Provides the clocking synchronization d. Controls the network
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24.
Choose the telephones or terminals that can operate in a VoIP network. Select all that apply: a. IP or Ethernet telephones b. "Softphone"-PC telephone software application or client c. Legacy telephone connected to IP network via gateway d. Any of the above
25.
When migrating from legacy to IP phones, which of the following is an incorrect statement regarding cabling and closets: a. There are more closets per area b. Single pair voice-grade cable cannot be retained c. Cabling run limits are reduced from 1000-2000 meters to 100 meters d. There are increased air conditioning requirements
26.
In general, IP networks have which of the following attributes: a. Cannot support peer-to-peer paths b. Do not share bandwidth among users c. Permits geographic-independence of elements/components d. Allows shared use of centralized resources
27.
Which of the following best describes the difference between Class of Service (CoS) and Quality of Service (QoS): a. QoS provides guaranteed bandwidth and performance, CoS does not b. Both provide priority access, hence they are equivalent c. CoS can be built-in, QoS can only be obtained by adding it later d. QoS applies only to WANs, CoS applies only to LANs Select the all the correct issues that effect an IP network’s performance. a. Available band width b. Class of Service c. Delay d. Packet Loss e. Transmission Errors
28.
29.
The primary signaling protocols for VoIP in the enterprise are: a. IP, TCP, and UDP b. H.323, SIP, and MGCP c. SIP, MEGACO, and H.248 d. RSVP, MPLS, and DiffServ
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