Nortel 920-803 Exam - Certifyme.com

Free 920-803 Sample Questions:

1. A video conference is in progress between two networked locations using gigabit Ethernet. The video conferencing application is using User Datagram Protocol (UDP) to transport the video and audio data. Why should UDP be used instead of Transmission Control Protocol (TCP)?
A. TCP CANNOT handle streaming data applications.
B. UDP is better than TCP at seamlessly synchronizing voice and video together.
C. UDP serves as an efficient transport for handling real-time application traffic.
D. UDP uses less bandwidth than TCP in a WAN, but more bandwidth than TCP in a LAN.
Answer: C

2. A customer reports that users are complaining about poor voice quality with VoIP calls. A technician has identified an Ethernet switch in the path for VoIP traffic that appears to be the cause of the poor voice quality. Which two configuration parameters, known to cause problems for VoIP traffic, should be checked on the Ethernet switch? (Choose two.)
A. Duplex setting
B. Autonegotiation
C. VLAN configuration
D. Spanning tree configuration
Answer: A, B

3. Given the following customer network information:
• The IP clients are located on a private network of 10.168.254.0/24 (site A) using many-to-one, port-based Network Address Translation (NAT).
• The H.323 gateway is located on the public network at 207.46.197.102 (site B) at a different location.
• The customer network between the IP clients and the H.323 gateway appears to be set up properly because you can ping from site A to site B.
A customer is complaining of a one-way speech path in this setup when calling from an IP client to the H.323 gateway. What is the most likely cause of this issue?
A. The IP clients on the private network need a gatekeeper on the private network to place calls to the H.323 gateway on the public network.
B. The IP clients on the private network need a media gateway on the public network to place calls to the H.323 gateway on the public network.
C. The H.323 gateway on the public network needs a media gateway on the private network to transcode the calls to the IP clients on the private network.
D. The IP clients on the private network use private addresses mapped to a single public address. The media path from the public address CANNOT reach the IP clients with the private address.
Answer: D

4. When a call is placed from an H.323 endpoint to another H.323 endpoint via an IP network, what is the function of the H.323 gatekeeper?
A. It maps the originating gateway IP address to destination gateway IP address.
B. It maps the originating telephone number to the originating gateway IP address.
C. It maps the destination telephone number to the destination gateway IP address.
D. It maps the destination telephone number to the destination endpoint IP address.
Answer: D

5. A customer wants to use VoIP on their LAN. They have deployed several H.323 endpoints. Which component is responsible for call control, media access, and bandwidth management between endpoints?
A. Proxy Server
B. H.323 Gateway
C. Media Gateway
D. H.323 Gatekeeper
Answer: D

6. A customer wants to implement VoIP on their LAN. What is the role of the gatekeeper in an IP network?
A. It converts media formats between divergent networks.
B. It performs address translation and bandwidth management.
C. It connects divergent networks by translating between signaling protocols for call setup and teardown.
D. It supports Internet Telephones with controller software acting as a Private Branch Exchange (PBX) to provide feature capabilities, and call setup through the use of a SIP INVITE to connect a call.
Answer: B

7. In an H.323 network the gatekeeper and the gateway work together to manage the interface between the VoIP network and the Public Switched Telephone Network (PSTN). Which two functions does the gatekeeper perform? (Choose two.)
A. determines call type
B. manages call routing
C. handles the dialing plan
D. manages the Call Detail Reporting (CDR)
Answer: B, C

8. VoIP requires an IP network to provide the following:
• end-to-end QoS
• low delay
• minimal jitter
• echo cancellation
• low packet loss
Which network devices should be deployed to achieve the "best" voice performance?
A. Layer 2/Layer 3 switches with 802.1q tagging enabled at the core network and managed hubs at the network edge.
B. Routers with filters at the network core and Layer 2 switches with Virtual LANs (VLANs) at the network edge.
C. Layer 2 switches at the core network with Differentiated Services (DiffServ) enabled and routers with 802.1p Class of Service (CoS) enabled at the network edge.
D. Layer 3 switches at the network core with DiffServ enabled and Layer 2 switches with 802.1p CoS enabled at the network edge.
Answer: D

9. In a Layer 3 IP LAN/WAN environment, which method provides the best control for managing applications with different types of QoS behaviors?
A. traffic shaping
B. platform queuing controls
C. Differentiated Services (DiffServ)
D. Internet Protocol (IP) fragmentation
E. Point-to-Point Protocol (PPP) fragmentation
Answer: C

10. A customer wants to implement VoIP on their LAN. Which two network devices should be used to avoid network congestion? (Choose two.)
A. routers
B. Ethernet hubs
C. Layer 2 switches
D. Layer 3 switches
E. shared-media Ethernet hubs
Answer: C, D


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