IP Services Q/A's

Question 1

What is Quality of Service (QOS) used for?

Answer 1

prioritize data traffic

Question 2

The standard traditional values for an acceptable video quality call for latency, jitter, loss are?

Answer 2

< 150ms Latency (delay)
< 30ms Jitter (variation in delay)
< 1% Loss

Question 3

In packet switching data packets are sent out in what order?

Answer 3

First in First Out (FIFO)

Question 4

When packets size limit is depleted what happens to new packets?

Answer 4

dropped

Question 5

What is Class of service in QOS used for?

Answer 5

prioritize data traffic

Question 6

What does NBAR stand for?

What is NBAR responsible for in QOS between layers 3 - 7?

Answer 6

Network-Based Application Recognition

deep packet inspection - marks and monitors data traffic

Question 7

Class Based Weighted Fair Queuing is used to do what in QoS?

Answer 7

divide bandwidth amongst different classes

Question 8

What is Low Latency Queuing used for?

Answer 8

add a strict priority to data traffic

Question 9

Class Maps specify what two things?

Answer 9

Class name and class type

Question 10

The service policy in QoS is also know as what type of Map?

Answer 10

Policy Map

Question 11

Service policy in QoS can only operate when it is enabled where?

Answer 11

interface

Question 12

What is Traffic shaping in QoS used for?

Answer 12

delaying traffic of certain threshold “buffer excess packets”

Question 13

When the rate limit is exceeded in QOS policing what happens?

Answer 13

packets drops

Question 14

The two things that syslogs manage are?

Answer 14

system logs and alert messages

Question 15

The command IP helper address forwards what information, where?

Answer 15

DHCP server information to another router not within it’s own network

Question 16

Dynamic Host Control Protocol DHCP is a centralized server that automates what?

Answer 16

auto configuration of IP addresses for hosts

Question 17

What are the four DHCP states (DORA) in order?

Answer 17

Acronym (DORA)

DCHP Discover (Broadcast)
DHCP Offer (Unicast/Broadcast)
DHCP Request (Broadcast)
DHCP Acknowledgement

Question 18

DNS Domain Name System is to resolve what?

Answer 18

IP address to host names

Question 19

What port does DNS use?

Answer 19

53

Question 20

DHCP snooping inspects and stop…?

DHCP snooping is enabled needs to be enabled on a?

Answer 20

malicious DHCP packets

Trusted Port

Question 21

What information does SNMP Simple Network Management Protocol collects?

Answer 21

network monitoring and management information

Question 22

The data variable in SNMP are organized into what type of Information base?

Answer 22

(MIB) Management Information Base

Question 23

What is Per-hop behavior (PHB)?

Answer 23

packets marked with forwarding precedence

Question 24

Trivial File Transfer Protocol TFTP is used to do what with remote host?

Answer 24

send or retrieve a single files

Question 25

TFTP is more or less secure over FTP

Answer 25

Less secure

Question 26

What port is TFTP?

Answer 26

port 69

Question 27

What two things is TFTP commonly used for?

Answer 27

hardware maintenance

system updates

Question 28

Does TFTP require authentication?

Answer 28

no

Question 29

There are how many connections established using TFTP for file transfer?

Answer 29

single connection

Question 30

With FTP what two things can you do between remote hosts?

Answer 30

File transfers and uploads

Question 31

What is the control port for FTP?

What is the data port for FTP?

Answer 31

port 20

Port 21

Question 32

What layer of DSCP in QOS typically does marking occur?

Answer 32

IP Header of Layer 3

Question 33

What does DSCP stand for in Qos?

DSCP is used to do what what with network traffic?

Answer 33

Differentiated Services Code Point

classify and manage traffic

Question 34

What type of service is used by a LAN in QoS?

Answer 34

(COS) Class of Service

Question 35

QOS Capabilities Syntax X(p), T(q), Z(t) mean what?

Answer 35

p = number of priority queues (max 1)
q = number of standard queues
t  = bandwidth thresholds

example 1p 4q 4t

Question 36

The two primary functions used by QoS in order to handle traffic are?

Answer 36

Classification and Queuing

Question 37

The type of memory buffers are used in QoS queues?

Answer 37

high-performance memory buffers

Question 38

What is the queuing scheduler called for congestion avoidance?

Answer 38

Weighted Random Early Detection (WRED)

Question 39

QoS when policing drops excess packets in what direction?

Answer 39

inbound and outbound

Question 40

How does QoS handle delayed shaped data traffic?

The direction of QoS shaping is applicable in what direction?

Answer 40

drops it

outbound direction

Question 41

CIR in QoS stand for?

The CIR from a service provider means what?

Answer 41

Committed Information Rate

Guaranteed bandwidth

Question 42

What is the formula for CIR?

What is the Bc?

What is the Tc?

Answer 42

CIR = Bc / Tc

Bc = Committed Burst number of bits for shaping or bytes for policing

Tc = Timing Interval

Question 43

What are the three sections listed in Cisco Modular Quality of Service CLI command line?

Answer 43

Class Map
Policy Map
Service Policies

Question 44

What is a Class Map?

Answer 44

type of traffic mapped to a policy

Question 45

The Policy Map is?

Answer 45

Set of defined policies