QOS

Question 1

Define Classification (QoS)

Answer 1

Packet ID and classification determines which treament that traffic should receive.

Question 2

Define Marking (QoS)

Answer 2

Packets are marked based on classification, metering, or both.

Question 3

CoS (QoS)

Answer 3

Used with Ethernet 802.1q and contains 3 bits

Question 4

ToS (QoS)

Answer 4

L3 IPv4 packet field and contains 8 bits

Question 5

DSCP (QoS)

Answer 5

6 bit value that describes the meaning of the L3 ToS Field

Question 6

TID (QoS)

Answer 6

Term used to describe a QoS field of wireless frames.

Question 7

Policers vs Shapers

Answer 7

Policiers - perform checks for traffic violations.

Shapers - Traffic smoothing tools.

Question 8

FIFO

Answer 8

First in, First Out

Single Queue of QoS packets

Question 9

PQ

Answer 9

Priority Queuing - Set of 4 queues that are served in strict priority queuing.

Question 10

CQ

Answer 10

Custom Queueing - Set of 16 queues

Question 11

WFQ

Answer 11

Weighted Fair Queueing. - algorithm to divide.

Question 12

CBWFQ

Answer 12

New QoS queuing with dynamic fairness of other flows.

Question 13

LLQ

Answer 13

CBQFW with strict prioirty.

Question 14

Which QoS mechanism will delay traffic if a session uses more than the allotted bandwidth?

Answer 14

Shaping

Question 15

Which queuing mechanism has a single queue and sends packets in the exact order that they arrived?

Answer 15

FIFO

Question 16

Which QoS mechanism is a congestion avoidance mechanism?

Answer 16

WRED

Question 17

What are the different QoS models?

Answer 17

1. Best-Effort - Used today
2. IntServ - sets aside bandwidth for apps that need it. Provides QoS to IP
3. DiffServ - Provides greater scalability.

Question 18

Pros and Cons of DiffServ

Answer 18

Pros:
High Scalable
Provides many different levels of quality.

Cons:
No absolute guarantee of service
Requires a set of complex mechanisms to work.

Question 19

BA

Answer 19

Behavior Aggregate

DiffServ Term

Collection of packets with the same DSCP value crossing a link in a particular direction.

Question 20

DSCP

Answer 20

DiffServ Term

Value in IP header that is used to select a QoS treatment for a packet.

Question 21

PHB

Answer 21

Per-Hop Behavior

DiffServ Term

Externally observable forwarding behavior.

Question 22

PHB EF

Answer 22

Used for low-delay service

101

Question 23

PHB AF

Answer 23

Used for guarantee bandwidth service

Question 24

Steps to ID Network Traffic in QoS

Answer 24

1. Network Audit
2. Business Audit
3. Sevice Level Review

Question 25

Where in an enterprise network should classification and marking be performed?

Answer 25

Access Layer

Question 26

Services are provided to which entities in the DiffServ model?

Answer 26

Classes of traffic