Infrastructure Services

Question 1

What type of protocol is HSRP

Answer 1

First Hop Redundancy Protocol FHRP

Question 2

What are the 3 main FHRPs

Answer 2

HSRP hot standby router protocol
VRRP virtual router redundancy protocol
GLBP gateway load balancing protocol

Question 3

What are the default HSRP hello/dead timers

Answer 3

3/10

Question 4

How does HSRP work

Answer 4

By using a virtual IP and MAC

Question 5

What is GARP

Answer 5

Gratuitous ARP - an arp message that wasn;t asked for

Question 6

What do all 3 FHRPs have in common

Answer 6

Redundancy focused
Virtual ip and macs
Keep alive timers

Question 7

Which two FHRPs are cisco proprietary

Answer 7

HSRP

GLBP

Question 8

What is the virtual mac address of HSRP ver 1

Answer 8

0000.0c09.ac–

Question 9

What is the virtual mac address of HSRP ver 2

Answer 9

0000.0c9f.f—

Question 10

What is the difference between HSRP ver 1 & 2

Answer 10

With ver 2, the hello timer can be set in milliseconds, ver 1 can’t.

Ver 1 and 2 are not compatible with each other

Question 11

How is HSRP configured

Answer 11

• Go to interface
• Standby version 2
• Standby 1 ip 10.1.55.1
• Standby 1 priority 150
• Standby 1 preempt

Question 12

What is preemption

Answer 12

it means that router regains primary router status should failover occur and issue be fixed.

Question 13

In HSRP, how is the primary router elected

Answer 13

By setting a higher priority

Question 14

What is Qos

Answer 14

Quality of service

The ability to dictate traffic treatment
o	Prioritization
o	Shaping / policing
o	Advanced strategies (WRED)
Strategies to fight the enemy
o	Delay
o	Jitter (differing delay between packets)
o	Packet loss

Question 15

What are the Qos audio requirements

Answer 15

• Jitter < 30ms
• Delay < 150 ms
• Loss < 1%
• Qos: dscp ef
• Bandwidth:little

Question 16

What are the Qos video requirements

Answer 16

• Jitter < 30ms
• Delay < 150 ms
• Loss < 1%
• Qos: dscp af41
• Bandwidth: lots

Question 17

What are some QOS tools that can be used.

Answer 17

Methods available
o	Classification and marking
o	Queueing (congestion management)
o	Congestion avoidance
o	Shaping and policing
Understand trust boundary

Question 18

What is classification

Answer 18

identifying what the traffic is.

Question 19

What is marking

Answer 19

= figures what the traffic is and puts a class of service (L2) or type of service (L3) in header

Question 20

What is taildrop

Answer 20

when packets are dropped because devices queue is full

Question 21

What is congestion avoidance

Answer 21

tries to prevent queueing in first place e.g WRED, when router selectively drops certain pieces of web traffic to stop queue from filling up, to allow mission critical traffic

Question 22

What is shaping

Answer 22

takes traffic that you want and curve it down, stops from consuming whole bandwidth

Question 23

what is Policing

Answer 23

dropping traffic we don’t like

Question 24

What are the identification tools and what are the action tools

Answer 24

Classification and marking = identification tools

Queueing, congestion avoidance, shaping & policing = action tools

Question 25

Why is it beneficial to move the network trust boundary closer to the end device?

Answer 25

• Because more devices perform the work of classification and marking

Question 26

What are the main queueing strategies

Answer 26

WFQ Weighted fair queueing
CB-WFQ classed based WFQ
LLQ low latency queueing

Question 27

What is WFQ

Answer 27

Weighted fair queueing (WFQ) – low traffic senders get priority over high traffic senders

Question 28

What is CB-WFQ

Answer 28

Class based WFQ – divides bandwidth among classes you define

Question 29

What is LLQ

Answer 29

Low latency queueing (LLQ) – combo of CB-WFQ, but adds a strict priority element, also called PQ-CBWFQ (Priority queue – class based weighted fair queueing)

Question 30

Where should a standard ACL be placed

Answer 30

Close to destination

Question 31

Where should an extended ACL be place

Answer 31

Close to source