Why is QoS important in a converged network?（）A、Because voice data packets must follow a single dedicated path through the networkB、Because voice data packets should arrive quickly and sequentially, and with no lost dataC、Because lost voice-data packets m

第1题：

Choose the false statement concerning the use of CiscoWorks Internetwork Performance Monitor (IPM) in a Teleworker deployment.（）

• A、IPM should not be run on a production network. 
• B、IPM helps verify if a Service Provider is meeting the Service Level Agreement. 
• C、IPM contains a database that can store data on latency, jitter, and drops of voice packets over a period of weeks or months. 
• D、The QoS service policy should contain an allocation of sufficient bandwidth in the priority queue (LLQ) for both the SAA probe simulating a voice call and the voice call. If not, voice quality will suffer.

第2题：

What ensures that voice packets are given priority throughout the network so that conversations arrive intact?（）

• A、Centrex
• B、Packet encryption
• C、Intelligent call routing
• D、QoS

第3题：

You work as a network technician at Company. Your boss， Mrs.， is interested in  LWAPP （Lightweight Access Point Protocol）.  What should you tell her regarding this technology？  （）

• A、 LWAPP is a proprietary protocol， and because of its very high overhead it is not widely adopted.
• B、 Control traffic is encapsulated in UDP packets with a source port of 1024 and a destination port  of 12223.
• C、 Layer 3 LWAPP is a UDP/IP Frame that requires a Cisco Aironet AP to obtain an IP address  using DHCP.
• D、 Data traffic is encapsulated in UDP packets with a source port of 1024 and a destination port of  12223.
• E、 Control traffic is encapsulated in TCP packets with a source port of 1024 and a destination port  of 12223.
• F、 Data traffic is encapsulated in TCP packets with a source port of 1024 and a destination port of  12223.

第4题：

When troubleshooting a network， the output of the command show interfaces indicates a large number of runts. What is a runt？（）

• A、the number of packets that are discarded because they exceed the maximum packet size of the medium
• B、errors created when the CRC generated by the originating LAN station or far-end device does not match the checksum calculated from the data received.
• C、the number of packets that are discarded because they are smaller than the minimum packet size of the medium
• D、the number of received packets that were ignored by the interface because the interface hardware ran low on internal buffers
• E、the number of times that the interface requested another interface within the router to slow down

第5题：

Why is QoS important in a converged network?（）

• A、Because data does not need to arrive intact, so data transfer rates can be variable
• B、Because lost voice-data packets must be retransmitted
• C、Because voice data packets should arrive quickly and sequentially, and with no lost data
• D、Because voice data packets must follow a single dedicated path through the network

第6题：

What ensures that voice packets are given priority throughout the network so that conversations arrive intact?（）

• A、QoS
• B、Centrex
• C、Packet encryption
• D、Intelligent call routing

第7题：

A stream of voice packets transmitted over a WAN network encounters differing queuing delays. One router in the path used by the voice packets delays some of the packets for 4 ms while transmitting a large video file， but delays other packets only 2 ms. Another router delays some packets 5 ms， but transmits others in 2 ms. How would you best describe this type of problem？（）

• A、end-to-end delay
• B、interference from bulk data traffic
• C、processing delays
• D、serialization delays
• E、jitter

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第13题：

Which two statements about the QoS policy generation phase of the Cisco SDM QoS wizard are true？ （）

• A、 The SDM QoS wizard will create two real-time traffic classes to handle VoIP and voice signaling packets.
• B、 The SDM QoS wizard will create three real-time traffic classes to handle VoIP， voice signaling， and video packets.
• C、 The SDM QoS wizard will create four real-time traffic classes to handle VoIP， voice signaling， video， and video streaming packets.
• D、 The SDM QoS wizard will create two business-critical traffic classes to handle transactional and network management packets.
• E、 The SDM QoS wizard will create three business-critical traffic classes to handle transactional， network management， and routing packets.
• F、 The SDM QoS wizard will create four business-critical traffic classes to handle transactional， network management， routing， and best-effort packets.

第14题：

Which two statements are true about Voice over IP （VoIP） packet delivery in a digital infrastructure？ （）

• A、 Packets can arrive out of order.
• B、 Packets must take the same path to the destination.
• C、 Once packets are received at the destination router， the router performs sampling to ensure the quality of the voice traffic.
• D、 Packets can experience varying delays across the network.
• E、 Packets containing voice samples are sequentially numbered by default， allowing for reordering upon arrival at the terminal router along the path.

第15题：

VOIP has been implemented at the main office of the Company network. Which two statements  are true about voice packets in a LAN？（）

• A、 Voice carrier stream utilizes Real-Time Transport Protocol (RTP) to carry the audio/media  portion of the VoIP communication.  
• B、 Voice traffic data flow involves large volumes of large packets.  
• C、 Because a packet loss involves a small amount of data, voice traffic is less affected by packet  losses than traditional data traffic is.  
• D、 Voice packets are encapsulated in TCP segments to allow for proper sequencing during  delivery. 
• E、 Voice packets are very sensitive to delay and jitter. 

第16题：

Which three practices are important to the implementation of a DiffServ QoS architecture？（）

• A、 Because services are allocated throughout the network before the transmission of data begins， traffic classes can be guaranteed QoS services.
• B、 Traffic classes are marked with Layer 2 markings to allow for more granularity in identifying traffic classes.
• C、 Traffic classes are marked with Layer 3 markings to allow them to traverse different network types without loss of QoS information.
• D、 Traffic classes allow networks to provide proper QoS treatment of packets without applications having to request services.
• E、 Based upon the network capabilities， QoS markings are placed on packets as needed throughout the network to allow for proper QoS treatment of packets.
• F、 QoS markings are placed on packets as close to the network edge as possible to allow distribution and core devices to determine QoS actions as quickly as possible.

第17题：

What are two major sources of delay that can be managed by QoS in voice-enabled networks？（）

• A、propagation delay
• B、voice packet serialization delay
• C、congested egress queues
• D、header overhead
• E、packets dropped because of CRC errors

第18题：

Authentication for user data traffic is important, but so is authentication for IP voice traffic. The Cisco 830 802.1 feature provides an easier method for allowing IP voice traffic through the VPN, because it（）.

• A、requires access lists to identify the voice traffic 
• B、can allow traffic from a device without 802.1X authentication, by MAC address
• C、can allow traffic from Cisco IP phones by listening to their CDP advertisements
• D、allows all packets marked with a ToS of 5 to bypass authentication
• E、allows all IP voice packets to bypass authentication via stateful inspection

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