M9 (QoS Concepts) 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 receieve 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 ta 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

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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

Classification

Traffic shaping

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

Speed mismatch

Jitter

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?

Jitter

Latency

Priority

Bandwidth

A

Latency

29
Q

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

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.

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.

A

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

30
Q

Which device would be classified as a trusted endpoint?

Switch

Router

Firewall

IP phone

A

IP phone

31
Q

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

If the request for bandwidth exceeds the amount of bandwidth available

If video traffic requests more bandwidth than voice traffic requests

If voice traffic latency begins to decrease across the network

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

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?

Video

Data

Voice

Management

A

Voice

33
Q

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

IntServ

DiffServ

Best-effort

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 sends the received traffic immediately.

The network device will drop the arriving packets.

The network device drops all traffic in the queue.

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

A

The netowk device will drop the arriving packets.

35
Q

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

It is delay sensitive.

It is bursty.

It can tolerate latency up to 400 ms.

It consumes few network resources.

It is insensitive to packet loss.

A

(It is delay sensitive) and (It consumes few network resources)

36
Q

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

DiffServ

Best-effort

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 forwarded along the pathway using a best-effort approach.

Data is forwarded along the pathway using DiffServ.

Data is not forwarded along the pathway.

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

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?

Voice traffic

Email

Web traffic

File transfers

A

Voice traffic

39
Q

Which queuing mechanism supports user-defined traffic classes?

FIFO

CBWFQ

WFQ

FCFS

A

CBWFQ

40
Q

What mechanism compensates for jitter in an audio stream by buffering packets and then replaying them outbound in a steady stream?

Digital signal processor

Playout delay buffer

Voice codec

WFQ

A

Playout delay buffer