QoS Flashcards

1
Q

What is the variable amount of time it takes for a frame to traverse the links between the source and destination?

Serialization delay.
Propagation delay.
Code delay.

A

Propagation delay.

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2
Q

What happens when congestion occurs?

Packet Loss.
Jitter.
Code delay.

A

Packet Loss.

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3
Q

What is the fixed amount of time it takes to transmit a frame from the NIC to the wire?

Serialization delay.
Jitter.
Code delay.

A

Serialization delay.

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4
Q

What is caused by variation in delay?

Congestion.
Packet loss.
Jitter.

A

Jitter.

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5
Q

Which type of traffic tends to consume a large portion of network capacity?

Voice.
Video.
Data.

A

Data.

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6
Q

Which type of traffic requires at least 384 Kbs of bandwidth?

Voice.
Video.
Data.

A

Video.

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7
Q

Which type of traffic is unpredictable, inconsistent, and bursty?

Voice.
Video.
Data.

A

Video.

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8
Q

Which type of traffic can be predictable and smooth?

Voice.
Video.
Data.

A

Voice.

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9
Q

Which type of traffic cannot be retransmitted if lost?

Voice.
Video.
Data.

A

Voice.

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10
Q

Which type of traffic must receive a higher UDP priority?

Voice.
Video.
Data.

A

Voice.

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11
Q

Which queuing algorithm simultaneously schedules interactive traffic to the front of a queue to reduce response time?

FIFO.
WFQ.
CBWFQ.
LLQ.

A

WFQ.

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12
Q

Which queuing algorithm provides support for user-defined traffic classes?

FIFO.
WFQ.
CBWFQ.
LLQ.

A

CBWFQ.

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13
Q

Which queuing algorithm is effective for large links that have little delay and minimal congestion?

FIFO.
WFQ.
CBWFQ.
LLQ.

A

FIFO.

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14
Q

Which queuing algorithm classifies traffic into different flows based on packet header addressing?

FIFO.
WFQ.
CBWFQ.
LLQ.

A

WFQ.

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15
Q

Which queuing algorithm allows delay-sensitive data such as voice to be sent before packets in other queues?

FIFO.
WFQ.
CBWFQ.
LLQ.

A

LLQ.

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16
Q

Which queuing algorithm applies priority, or weights, to identify traffic and classify it?

FIFO.
WFQ.
CBWFQ.
LLQ.

A

WFQ.

17
Q

Which QoS model provides per-request policy admission control?

Best effort.
Integrated services.
Differential services.

A

Integrated services.

18
Q

Which QoS model requires no special QoS mechanisms?

Best effort.
Integrated services.
Differential services.

A

Best effort.

19
Q

Which QoS model provides many different levels of quality?

Best effort.
Integrated services.
Differential services.

A

Differential services.

20
Q

Which QoS model uses explicit end-to-end resource admission control?

Best effort.
Integrated services.
Differential services.

A

Integrated services.

21
Q

Which QoS model is the most scalable?

Best effort.
Integrated services.
Differential services.

A

Differential services.

22
Q

Which detects when traffic rates reach a configured maximum rate and drops excess traffic?

Traffic policing.
Traffic shaping.
Classification.

A

Traffic policing.

23
Q

Which determines what class of traffic packets or frames belong to.

Marking.
Traffic shaping.
Classification.

A

Classification.

24
Q

Which adds a value to the packet header?

Marking.
Classification.
802.1Q

A

Marking.

25
Q

Which provides buffer management and allows TCP traffic to throttle back before buffers are exhausted?

Traffic policing.
802.1Q.
WRED.

A

WRED.

26
Q

Which retains excess packets in a queue and then schedules the excess for later transmission over increments of time?

WRED.
Traffic policing.
Traffic shaping.

A

Traffic shaping.

27
Q

What is the term used to indicate a variation of delay?

Latency.
Serialization delay.
Jitter.
Speed mismatch.

A

Jitter.

28
Q

A 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?

Bandwidth.
Jitter.
Priority.
Latency.

A

Latency.

29
Q

What role do network devices play in the IntServ QoS model?

Network devices are configured to service multiple classes of traffic and handle traffic as it may arrive.

Network devices use QoS on a hop-by-hop basis to provide excellent scalability.

Network devices ensure that resources are available before traffic is allowed to be sent by a host through the network.

Network devices provide a best-effort approach to forwarding traffic.

A

Network devices are configured to service multiple classes of traffic and handle traffic as it may arrive.

30
Q

Which device would be classified as a trusted endpoint?

Firewall.
Router.
IP phone.
Switch.

A

IP phone.

31
Q

Under which condition does congestion occur on a converged network with voice, video, and data traffic?

If video traffic requests more bandwidth than voice traffic requests.

If the request for bandwidth exceeds the amount of bandwidth available.

If a user downloads a file that exceeds the file limitation that is set on the server.

If voice traffic latency begins to decrease across the network.

A

If the request for bandwidth exceeds the amount of bandwidth available.

32
Q

Which type of traffic does Cisco recommend be placed in the strict priority queue (PQ) when low latency queuing (LLQ) is being used?

Voice.
Management.
Data.
Video.

A

Voice.

33
Q

Which model is the only QoS model with no mechanism to classify packets?

Best-effort.
DiffServ.
IntServ.
Hard QoS.

A

Best-effort.

34
Q

What happens when the memory queue of a device fills up and new network traffic is received?

The network device queues the received traffic while sending previously received traffic.

The network device sends the received traffic immediately.

The network device drops all traffic in the queue.

The network device will drop the arriving packets.

A

The network device will drop the arriving packets.

35
Q

What are two characteristics of voice traffic? (Choose two.)

It is bursty.
It consumes few network resources.
It can tolerate latency up to 400 ms.
It is insensitive to packet loss.
It is delay sensitive.

A

It consumes few network resources.
It is delay sensitive.

36
Q

Which QoS model is very resource intensive and provides the highest guarantee of QoS?

Best-effort.
DiffServ.
IntServ.
Soft QoS.

A

IntServ.

37
Q

What happens when an edge router using IntServ QoS determines that the data pathway cannot support the level of QoS requested?

Data is not forwarded along the pathway.

Data is forwarded along the pathway using intServ but not provided preferential treatment.

Data is forwarded along the pathway using DiffServ.

Data is forwarded along the pathway using a best-effort approach.

A

Data is not forwarded along the pathway.

38
Q

In QoS models, which type of traffic is commonly provided the most preferential treatment over all other application traffic?

File transfers.
Voice traffic.
Email.
Web traffic.

A

Voice traffic.

39
Q

Which queuing mechanism supports user-defined traffic classes?

FCFS.
CBWFQ.
FIFO.
WFQ.

A

CBWFQ.