642-437 Implementing Cisco Unified Communications Voice over IP and QoS v8.0 (CVOICE v8.0)

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Question 1


Answer :

Question 2

What is the reason that an outgoing call succeeds when COR is applied to the incoming
dial peer, but no COR is applied to the outgoing dial peer?

  • A. The COR list for incoming calls on the incoming dial peer is a superset of COR lists for outgoing calls on the outgoing dial peer.
  • B. COR lists for incoming calls on the incoming dial peer are not a superset of COR lists for outgoing calls on the outgoing dial peer.
  • C. The outgoing dial peer, by default, has the lowest priority.
  • D. The incoming dial peer, by default, has the highest COR priority when no COR is applied.

Answer : C

Question 3

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

Answer :

Question 4

When deploying an 802.3af switch what is the default number of Watts consumed by each
port if 802.3af compliant devices are attached to the switch?

  • A. 4 Watts
  • B. 6.3 Watts
  • C. 7 Watts
  • D. 15.4 Watts
  • E. 22.3 Watts

Answer : D

Question 5

A small office needs to provide outbound dialing and in-bound DID without the cost of a T1
circuit. All signaling is loop start. Which analog port configuration will support these

  • A. voice-port 0/0/0 description fxs-did signal did loop-start ! voice-port 0/1/0 description fxo signal loop-start ! dial-peer voice 1 pots incoming called-number . direct-inward-dial port 0/0/0 ! dial-peer voice 90 pots destination-pattern 9T port 0/1/0
  • B. voice-port 0/0/0 signal loop-start ! voice-port 0/1/0 signal loop-start ! dial-peer voice 1 pots incoming called-number T direct-inward-dial ! dial-peer voice 90 pots destination-pattern 9T port 0/1/0
  • C. voice-port 0/1/0 signal did loop-start ! dial-peer voice 1 pots incoming called-number . ! dial-peer voice 90 pots destination-pattern 9T port 0/1/0
  • D. voice-port 0/0/0 signal did loop-start ! dial-peer voice 1 pots incoming called-number . direct-inward-dial ! dial-peer voice 90 pots destination-pattern 9T port 0/0/0

Answer : A

Question 6

How does LLQ ensure that voice traffic is always expedited?

  • A. LLQ adds WRED to CBWFQ. This allows delay-sensitive data such as voice to be dequeued and sent first.
  • B. LLQ uses CBWFQ to prioritize voice traffic and by dequeuing the voice packets so they can be handled first.
  • C. The strict priority queue has a higher weight than the queues in CBWFQ. This weight allows the delay-sensitive data such as voice to be dequeued and sent first.
  • D. The LLQ strict priority queue allows delay-sensitive data such as voice to be dequeued and sent first (before packets in other queues are dequeued), giving delay-sensitive data preferential treatment over other traffic.

Answer : D

Explanation: Without Low Latency Queueing, CBWFQ provides weighted fair queueing based on defined classes with no strict priority queue available for real-time traffic. This scheme poses problems for voice traffic that is largely intolerant of delay, especially variation in delay. For voice traffic, variations in delay introduce irregularities of transmission manifesting as jitter in the heard conversation. The Low Latency Queueing feature provides strict priority queueing for CBWFQ, reducing jitter in voice conversations. Configured by the priority command, Low Latency Queueing enables use of a single, strict priority queue within CBWFQ at the class level, allowing you to direct traffic belonging to a class to the CBWFQ strict priority queue. http://www.cisco.com/en/US/docs/ios/12_0t/12_0t7/feature/guide/pqcbwfq.html

Question 7

Answer :

Question 8

Which statement best describes dial peers in a voice gateway. (Choose two.)

  • A. Dial peers are call legs that are used to identify call source and destination endpoints and to define the characteristics that are applied to each call leg in the call connection.
  • B. Dial peers are configured with call legs that are essential to implementing dial plans and providing voice services over an IP packet network.
  • C. A dial peer is a physical addressable endpoint in a voice gateway.
  • D. Dial peers create physical connections called call legs to complete an end-to-end call.

Answer : A,C

Question 9

Refer to the exhibit.

How does a switch port that receives marked traffic from a Cisco IP phone use the mls qos
trust cos command?

  • A. The CoS setting is modified according to the CoS-to-DSCP map.
  • B. CoS is used to select the ingress and egress queues.
  • C. For non-IP packets, the CoS is set to 7 and DSCP-to-CoS mapping is not applied.
  • D. The DSCP-to-CoS map is applied.

Answer : A

Question 10

Refer to the exhibit. When an inbound PSTN call to 4087071222 is received by the router
that is shown in the exhibit, what is the resulting called number?

  • A. 14087071222
  • B. 11222
  • C. 14081222
  • D. 1222
  • E. 4087071222

Answer : D

Explanation: /^.*\(.$\) Truncates Numbers down to the last 4 digits. http://www.cisco.com/en/US/tech/tk652/tk90/technologies_tech_note09186a0080325e8e.s html

Question 11

Refer to the exhibit. What will the class map do if a packet arrives that is marked with a
CoS of 6 and a DSCP value of EF?

  • A. The class map will match the packet and forward it to the policy map to be marked.
  • B. The class map will not map the packet and no QoS will be applied
  • C. The class map will wait for the next packet in the stream to see if it has a CoS marking of 5 and then forward both packets to the policy map.
  • D. For the packet to be forwarded to the policy map, it must have either a CoS of 5 or a DSCP value of EF.

Answer : B

Explanation: If there is no match for a packet, no QoS processing occurs on the packet and the switch offers best-effort service to the packet. http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_25_see/ configuration/guide/swqos.html

Question 12

Which codec complexity type will offer the greatest number of voice channels, provided that
the complexity type is compatible with the particular codecs that are in use?

  • A. low complexity
  • B. medium complexity
  • C. high complexity
  • D. flex complexity

Answer : A

Explanation: Codec complexity refers to the amount of processing required to perform voice compression. Codec complexity affects the call densitythe number of calls reconciled on the DSPs. With higher codec complexity, fewer calls can be handled. Select a higher codec complexity if that is required to support a particular codec or combination of codecs. Select a lower codec complexity to support the greatest number of voice channels, provided that the lower complexity is compatible with the particular codecs in use. http://www.cisco.com/en/US/docs/ios/12_3t/voice/command/reference/vrht_c6_ps5207_TS D_Products_Command_Reference_Chapter.html

Question 13

Which type of voice port supports immediate-start, wink-start, and delay-start followed by
pulse or DTMF tones?

  • A. FXS
  • B. FXS-DID
  • C. FXO
  • D. E&M

Answer : D

Question 14

Refer to the exhibit. Which type of ephone-dn is configured for the two ephones that are

  • A. single-line-octo
  • B. hunt line
  • C. shared-line, nonexclusive
  • D. two directory numbers with one telephone number
  • E. shared-line, overlay
  • F. octo-line

Answer : E

Explanation: The above exhibit shows the configuration for a simple shared-line overlay set. The primary ephone-dn that is configured for each phone is unique while the remaining ephone-dns 10, 11, and 12 are shared in the overlay set on both phones. The primary ephone-dn in a shared-line overlay set is configured unique to the phone to guarantee that the phone has a line available for outgoing calls, and to ensure that the phone user can obtain dial-tone even when there are no idle lines available in the rest of the shared-line overlay set. Using a unique ephone-dn also provides a unique calling party identity on outbound calls made by the phone so that the called user can see which specific phone is calling. http://www.cisco.com/en/US/docs/voice_ip_comm/cucme/admin/configuration/guide/cmeco ver.html#wp1099687

Question 15

Refer to the exhibit. Your company's QoS policy states that all traffic that is arriving at
access layer switches from IP phones should be marked with a DSCP value of 46 and that
all untagged traffic that is arriving from a PC that is attached to an IP phone should be
marked with a CoS value of 1. Which two options will satisfy the requirements for the CoS-
to-DSCP map and are the correct QoS commands? (Choose two.)

  • A. mls qos 1
  • B. mls qos map cos-dscp 0 10 18 26 34 46 48 56
  • C. mls qos cos 1
  • D. mls qos map dscp 0 8 16 26 32 40 48 56
  • E. mls qos map cos 0 8 18 26 40 48 50 56
  • F. mls qos dscp 1

Answer : B,C

Explanation: To define the ingress Class of Service (CoS)-to-differentiated services code point (DSCP) map for trusted interfaces, use the mls qos map cos-dscp command in global configuration mode. mls qos map cos-dscp dscp1...dscp8 dscp1...dscp8 - Defines the CoS-to-DSCP map. For dscp1...dscp8, enter eight DSCP values that correspond to CoS values 0to 7. Separate consecutive DSCP values from each other with a space. The supported DSCP values are 0, 8, 10, 16, 18, 24, 26, 32, 34, 40, 46, 48, and 56. To define the default multilayer switching (MLS) class of service (CoS) value of a port or to assign the default CoS value to all incoming packets on the port, use the mls qos cos command in interface configuration mode. mls qos cos cos-value cos-value - Assigns a default CoS value to a port. If the port is CoS trusted and packets are untagged, the default CoS value is used to select one output queue as an index into the CoS-to-DSCP map. The CoS range is 0 to 7. The default is 0. http://www.cisco.com/en/US/docs/ios/qos/command/reference/qos_m2.html#wp1041343

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