Time limit: 0
Quiz-summary
0 of 21 questions completed
Questions:
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
Information
Good luck!
You have already completed the quiz before. Hence you can not start it again.
Quiz is loading...
You must sign in or sign up to start the quiz.
You have to finish following quiz, to start this quiz:
Results
0 of 21 questions answered correctly
Your time:
Time has elapsed
You have reached 0 of 0 points, (0)
Average score |
|
Your score |
|
Categories
- Not categorized 0%
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- Answered
- Review
-
Question 1 of 21
1. Question
1 pointsWhen QoS is implemented in a converged network, which two factors can be controlled to improve network performance for real-time traffic? (Choose two.)Correct
Incorrect
Hint
Delay is the latency between a sending and receiving device. Jitter is the variation in the delay of the received packets. Both delay and jitter need to be controlled in order to support real-time voice and video traffic. -
Question 2 of 21
2. Question
1 pointsA network engineer performs a ping test and receives a value that shows the time it takes for a packet to travel from a source to a destination device and return. Which term describes the value?Correct
Incorrect
Hint
Latency refers to the time it takes for a packet to travel from a source device to a destination device. Jitter is the variation in the latency values of received packets. Bandwidth is the measurement of how much traffic is transmitted in a single second. Priority is the preferential treatment of specific classes of traffic. -
Question 3 of 21
3. Question
1 pointsWhat are two characteristics of voice traffic? (Choose two.)Correct
Incorrect
Hint
Voice traffic does not consume a lot of network resources, such as bandwidth. However, it is very sensitive to delay and dropped packets cannot be retransmitted. For good voice quality, the amount of latency should always be less than 150 milliseconds. -
Question 4 of 21
4. Question
1 pointsHow does a Cisco router using tail drop handle congestion when a traffic queue becomes full?Correct
Incorrect
Hint
Tail drop is also known as packet drop and is used by a router to discard any packet that arrives at the tail end of a queue. Tail drop treats all traffic equally and does not differentiate between delay-sensitive data and other traffic. -
Question 5 of 21
5. Question
1 pointsFor classifying packets into classes with CBWFQ, what is the purpose of configuring a maximum packet limit for a class?Correct
Incorrect
Hint
The maximum packet limit characteristic is the maximum number of packets allowed to accumulate in the queue for a specific class that is defined using CBWFQ. -
Question 6 of 21
6. Question
1 pointsA network engineer is selecting a QoS method to control congestion on a VPN tunnel link between the headquarters site and a branch office. Which queuing method cannot be used to classify and control VPN traffic?Correct
Incorrect
Hint
Weighted fair queuing (WFQ) does not support tunneling and encryption because these features modify the packet content information required by WFQ for classification. -
Question 7 of 21
7. Question
1 pointsAn administrator has mastered the use of access control lists (ACLs) and wants to deploy QoS by defining different traffic classes through the use of ACLs. Which queuing method provides this functionality?Correct
Incorrect
Hint
Class-based weighted fair queuing (CBWFQ) provides support for user-defined traffic classes. CBWFQ allows an administrator to define traffic classes based on match criteria such as protocols, access control lists (ACLs), and input interfaces. -
Question 8 of 21
8. Question
1 pointsWhich queuing algorithm has only a single queue and treats all packets equally?Correct
Incorrect
Hint
FIFO queuing sends packets out an interface in the order that they had arrived and does not make a decision about packet priority. All packets are treated equally. -
Question 9 of 21
9. Question
1 pointsA network administrator is deploying QoS with the ability to provide a special queue for voice traffic so that voice traffic is forwarded before network traffic in other queues. Which queuing method would be the best choice?Correct
Incorrect
Hint
Low latency queuing (LLQ) allows delay-sensitive data, such as voice traffic, to be defined in a strict priority queue (PQ) and to always be sent first before any packets in any other queue are forwarded. -
Question 10 of 21
10. Question
1 pointsWhat are two characteristics of DiffServ QoS model? (Choose two.)Correct
Incorrect
Hint
The DiffServ QoS model is commonly used in modern networks and is the easiest QoS model to deploy. TCP flows are grouped into a single class. Network devices are setup to service multiple classes of traffic where each class of traffic has different QoS requirements. -
Question 11 of 21
11. Question
1 pointsWhat are two characteristics of the best-effort QoS model? (Choose two.)Correct
Incorrect
Hint
The best-effort QoS model provides no guarantees and it is commonly used on the Internet. The best-effort QoS model treats all network packets in the same way. -
Question 12 of 21
12. Question
1 pointsWhat role do network devices play in the IntServ QoS model?Correct
Incorrect
Hint
The IntServ QoS model uses resource reservation to guarantee bandwidth and packet-loss rates from end to end. IntServ uses a connection-oriented approach to ensure that available resources are sufficient in the network for the traffic to have a specific level of QoS. -
Question 13 of 21
13. Question
1 pointsWhich QoS model is very resource intensive and provides the highest guarantee of QoS?Correct
Incorrect
Hint
The IntServ QoS model uses resource reservation and admission control mechanisms to schedule network resources. -
Question 14 of 21
14. Question
1 pointsIn QoS models, which type of traffic is commonly provided the most preferential treatment over all other application traffic?Correct
Incorrect
Hint
Voice traffic from IP phones is commonly provided preferential treatment over all other application traffic such as email, web traffic, and file transfers. -
Question 15 of 21
15. Question
1 pointsWhat are two approaches to prevent packet loss due to congestion on an interface? (Choose two.)Correct
Incorrect
Hint
There are three approaches to prevent sensitive traffic from being dropped: Increase link capacity to ease or prevent congestion. Guarantee enough bandwidth and increase buffer space to accommodate bursts of traffic from fragile flows. Prevent congestion by dropping lower-priority packets before congestion occurs. -
Question 16 of 21
16. Question
1 pointsWhat two fields are available in IPv4 and IPv6 headers to mark packets for QoS? (Choose two.)Correct
Incorrect
Hint
IPv4 uses an 8-bit Type of Service field to mark packets at Layer 3 and IPv6 uses an 8-bit Traffic Class field to mark packets at Layer 3. The fields are used by receiving devices to forward the packets based on the appropriate assigned QoS policy. -
Question 17 of 21
17. Question
1 pointsWhat is the benefit of deploying Layer 3 QoS marking across an enterprise network?Correct
Incorrect
Hint
Marking traffic at Layer 2 or Layer 3 is very important and will affect how traffic is treated in a network using QoS. Layer 2 marking of frames can be performed for non-IP traffic. Layer 2 marking of frames is the only QoS option available for switches that are not “IP aware.” Layer 3 marking will carry the QoS information end-to-end. -
Question 18 of 21
18. Question
1 pointsWhich QoS technology provides congestion avoidance by allowing TCP traffic to be throttled before buffers become full and tail drops occur?Correct
Incorrect
Hint
The weighted random early detection (WRED) algorithm provides congestion avoidance on network interfaces by allowing TCP traffic to be throttled before buffers are exhausted. This maximizes network use and TCP-based application performance while minimizing tail drop. -
Question 19 of 21
19. Question
1 pointsRefer to the exhibit. As traffic is forwarded out an egress interface with QoS treatment, which congestion avoidance technique is used?Correct
Incorrect
Hint
Traffic shaping buffers excess packets in a queue and then forwards the traffic over increments of time, which creates a smoothed packet output rate. Traffic policing drops traffic when the amount of traffic reaches a configured maximum rate, which creates an output rate that appears as a saw-tooth with crests and troughs. -
Question 20 of 21
20. Question
1 pointsWhich QoS model uses the DSCP bits to mark packets and provides 64 possible classes of service?Correct
Incorrect
Hint
The DiffServ model uses 6-bits known as the DiffServ Code Point (DSCP) bits to mark traffic and offers a maximum of 64 possible classes of service. Diffserv-aware routers can then implement per-hop behaviors (PHBs) that can control packet forwarding based on the specified class of service. -
Question 21 of 21
21. Question
1 pointsWhich QoS technique retains excess packets in a separate queue for later transmission?Correct
Incorrect
Hint
As network traffic exits an interface it is queued and then shaped to smooth out the packet output rate. Classification and marking should occur early on to identify traffic and classify how the traffic should be treated.