Unit 4

Question 1

The default behavior on the network is process traffic
on a “first come, first serve” basis. This is called:

Answer 1

First In, First Out (FIFO)

Question 2

___ provides different priority to different applications, users, or data flows, to guarantee a certain level of performance.

Answer 2

Quality of Service (QoS)

Question 3

What are the QoS Principles?

Answer 3

Latency -Time it takes for packet to reach destination

Jitter -Variation in delay that effects video/audio quality

Dropped Packets -Packets that do not make it to destination

Low Throughput - Data stream too low for real-time media services from devices using the same resources

Out-of-Order Delivery - packets arrive out of order

Question 4

Today’s wired Ethernet networks are ___-duplex, while wireless Ethernet networks are ___-duplex.

Answer 4

full-duplex
half-duplex

Question 5

____ is a field in an IP packet that enables different levels of service in network traffic.

Answer 5

Differentiated Services Code Point (DSCP)

Question 6

In DSCP, There are two service types called:

Answer 6

guaranteed service and control load service.

Question 7

In DSCP, ___ ___ provides high-quality quantifiable guarantees with bounded (guaranteed minimum) latency.

Answer 7

Guaranteed service

Question 8

In DSCP, ___ ___ ___ provides high-quality quantifiable guarantees without bounded latency.

Answer 8

Controlled load service

Question 9

DSCP has two methods of filtering:

Answer 9

port number
deep packet inspection

Question 10

The following describes which DSCP filtering type?

 Fast
 Low resource-consuming
 Supported by many network devices
 Does not implement the application-layer payload, so user privacy is not compromised
 Useful only for the applications and services, which use fixed port numbers
 Easy to cheat by changing the port number in the system

Answer 10

Port Number

Question 11

The following describes which DSCP filtering type?

 Inspects the actual payload of the packet
 Detects the applications and services regardless of the port number used in the packet
 Lacks support for many applications, like Skype, which is poorly supported by most
classifiers
 Slow
 Requires a lot of processing power
 Signatures must be kept up to date, as the applications change frequently
 Applications that use encryption makes deep packet inspection nearly impossible

Answer 11

Deep Packet Inspection

Question 12

There are three different types of traffic classification. These traffic classes determine the priority they receive in a network.

Answer 12

Sensitive Traffic
Best Effort Traffic
Undesired Traffic

Question 13

The following describes which type of DSCP traffic?

___ ___ is data traffic that the operator has an expectation of being delivered on time. This includes VoIP, online gaming, video conferencing, and some web browsing.

Answer 13

Sensitive Traffic

Question 14

The following describes which type of DSCP traffic?

___ ___ ___ is all other kinds of non-detrimental traffic. This is traffic that the Internet Service Provider (ISP) deems isn’t sensitive to QoS metrics (jitter, packet loss, latency). A typical example would be peer-to-peer and email applications. Traffic management schemes are generally tailored so that best-effort traffic gets what is left after sensitive traffic.

Answer 14

Best Effort Traffic

Question 15

The following describes which type of DSCP traffic?

___ ___ is generally limited to the delivery of spam and traffic created by worms, botnets, and other malicious attacks. In some networks, this definition can include such traffic as non- local VoIP (for example, Skype) or video streaming services to protect the market for the ‘in- house’ services of the same type. In these cases, traffic classification mechanisms identify this traffic, allowing the network operator to either block this traffic entirely or severely hamper its operation.

Answer 15

Undesired traffic