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killexams.com


Nortel


920-803


Technology Standards and Protocol for IP Telephony Solutions


https://killexams.com/pass4sure/exam-detail/920-803

Which two statements accurately describe the G.107 E-Model? (Choose two.)


  1. The scale is typically from 1 to 5.

  2. The scale is typically from 50 to 94.

  3. It is a subjective model for use in transmission planning.

  4. It is a computational model for use in transmission planning.

  5. It is the numerical average of the voice quality ratings (scores) from all listeners.


Answer: B, D


QUESTION: 48

Click the calculator button. A customer with a low-speed, data - network link between two

locations wants to pass two concurrent VoIP calls between locations. Their top priority is the best possible voice quality to meet call requirements and network capacity. Typically, which CODEC should best meet their network requirements?


A. G.711 B. G.723.1 C. G.726

D. G.729A


Answer: D


QUESTION: 49

Which two items factor into VoIP delay, jitter, and packet loss on a QoS-enabled IP network?

(Choose two.)


  1. CODEC selection

  2. redundant H.323 gateway

  3. signaling protocol selection

  4. packetization rate selection

  5. 323 gatekeeper placement


Answer: A, D

Which queuing technique services the queues using a round-robin approach to prevent any one packet source from overusing its share of network capacity?


  1. Fair Queuing

  2. Priority Queuing

  3. Weighted Fair Queuing (WFO)

  4. First-In, First-Out (FIFO) Queuing


Answer: A


QUESTION: 51

A customer wants to connect a VoIP gateway from an IP-enabled Private Branch Exchange

(PBX) to its existing Ethernet Layer 2 switch. Internet Telephones will be directly attached to the Ethernet Layer 2 switch. In this situation using only Layer 2 technology, which two QoS methods should achieve the best voice quality using QoS prioritization? (Choose two.)


  1. Port-based Prioritization

  2. Socket-based Prioritization

  3. Traffic Separation using VLANs

  4. Differentiated Services (DiffServ)


Answer: A, C


QUESTION: 52

Which queuing technique: 1) classifies and places packets into queues according to the

information in the packets and 2) services packets from queues with the most important information first when congestions occurs?


  1. Fair Queuing

  2. Priority Queuing

  3. Class-Based Queuing (CBQ)

  4. Weighted Fair Queuing (WFQ)


Answer: B

Which statement best describes the operation used by an echo canceller to reduce echo in digital circuits?


  1. It places a large loss (attenuation) in the transmit path when it detects a signal on the receive path.

  2. It calculates an estimate of what the echo will be, and then subtracts this from the actual

    returned signal.

  3. It develops a mathematical model of the echo that will occur, and then adds this to the

    signal in the echo return path.

  4. It detects a signal on the incoming or outgoing path, and then switches gain into the other

path to increase the level of any returning signal.


Answer: B


QUESTION: 54

Click the calculator button. Given the following customer network information:

A fractional T1/E1 (384 kbps) is running between two sites. The data traffic peak usage is 80 kbps.

There are 24 Internet Telephones at each site with five calls expected to be traversing the T1/E1 WAN link at any one time.

A test across the WAN T1/E1 link shows a one-way delay of 125 ms.

Due to the network architecture calls from the Internet Telephones through the VoIP

gateways are incurring transcoding.

When Internet Telephones communicate with the VoIP gateway for calls traversing the WAN

router, what is the recommended CODEC for them to operate efficiently within the allotted WAN bandwidth and still provide good voice quality?


A. G.711 B. G.723.1 C. G.726

D. G.729A


Answer: D


QUESTION: 55

A customer is running voice and data traffic between two sites over a WAN. They are planning

to connect VoIP gateways in IP-enabled Private Branch Exchanges (PBXs) to existing Ethernet Layer 3 switches at each site. In this situation, which QoS method should achieve the best voice quality using QoS prioritization?


  1. Port Prioritization

  2. IP Address Prioritization

  3. Traffic Separation using VLANs

  4. Differentiated Services (DiffServ)


Answer: D