M7Q36: Quality of Service

Question 1

QoS refers to the technologies used to reserve bandwidth and give priority to certain applications and specific network traffic. The term QoS means _________________________.

A. Queuing or Shaping
B. Quality of Service
C. Queue of Segments
D. Quantity of Streams

Answer 1

B. Quality of Service

Explanation: QoS is an acronym for “Quality of Service” which includes all of the technologies and protocols that are available for ensuring the quality of specific network services and traffic.

Question 2

Quality of Service is necessary for the proper function of Voice over IP.

A. True
B. False

Answer 2

A. True

Explanation: Voice over IP traffic is real-time and very sensitive to things like jitter, latency, and dropped packets. Networks with Voice over IP require QoS to make sure there is always bandwidth available for phone calls even during times of congestion, and that phone calls get priority over other data passing through the network.

Question 3

DSCP (DiffServ) is a mechanism for marking packets with QoS information so that routers are able to apply QoS controls such as prioritizing traffic and reserving bandwidth during time of congestion. DSCP works at which layer of the OSI model?

(choose one)

A. Layer 1
B. Layer 2
C. Layer 3
D. Layer 4
E. Layer 5
F. Layer 6
G. Layer 7

Answer 3

C. Layer 3

Explanation: DSCP is a marking for IP Packets which are recognized by routers. DSCP works at Layer 3 of the OSI Model.

Question 4

CoS (Class of Service) is a mechanism for marking packets with QoS information so that switches are able to apply QoS controls such as prioritizing traffic and reserving bandwidth during time of congestion. CoS works at which layer of the OSI model?

(choose one)

A. Layer 1
B. Layer 2
C. Layer 3
D. Layer 4
E. Layer 5
F. Layer 6
G. Layer 7

Answer 4

B. Layer 2

Explanation: CoS is a marking for Ethernet Frames which are recognized by switches. CoS works at Layer 2 of the OSI Model.

Question 5

Traffic Shaping is a term for defining the amount of network bandwidth reserved for specific protocols and applications. To enforce traffic shaping rules QoS mechanisms such as DSCP and CoS tags are used.

A. True
B. False

Answer 5

A. True

Explanation: Traffic Shaping is the concept of reserving bandwidth for specific applications and protocols and uses QoS technologies to implement the traffic shaping rules.