Dynamic Routing Protocols

Question 1

What are the two distance vector protocols?

Answer 1

RIP and EIGRP

Question 2

What is an example of a link state protocol

Answer 2

OSPF or IS-IS

Question 3

What is an example of a path vector protocol

Answer 3

BGP

Question 4

Give an exampe of an EGP

Answer 4

BGP

Question 5

Give an exampe of an IGP

Answer 5

OSPF, RIP or EIGRP

Question 6

What are two routes that are automatically added when you connect two routers?

Answer 6

Connected and Local

Question 7

What is a “Connected” route

Answer 7

A route to a directly connected network

Question 8

What is a “Local” Route?

Answer 8

A route to a specific host. (The neighbour’s NIC)

Question 9

How do distance vectors algorithms work?

Answer 9

They send information about a known destination network and the metric to reach it.

Question 10

What is “routing by rumour”?

Answer 10

In distance vector algorithms, routers only know what they are told by other routers.

Question 11

How do link state protocols work?

Answer 11

Each router creates the same map of the network. Each router makes its own calculation to find the best route.

Question 12

What is an advantage of link state protocols over distance vector protocols?

Answer 12

They are faster to react to changes in the network.

Question 13

What is an advantage of distance vector protocols over link state protocols?

Answer 13

Requires less CPU of the router due to not calculating as much information.

Question 14

A router dynamically learns two routes. Which does it consider the best?

Answer 14

The route with the lowest metric.

Question 15

What happens if two routes to the same destination have the same cost?

Answer 15

Both routes will be added to the routing table and the traffic will be load-balanced. This is called ECMP (Equal Cost Multi Path) load balancing.

Question 16

What is ECMP load balancing?

Answer 16

Equal Cost Multi Path load balancing.

Question 17

A route’s cost is listed as [110/3] in the routing table. Which is the metric and which is the administrative distance?

Answer 17

AD= 110
Metric = 3

Question 18

What is a metric?

Answer 18

The cost of a route to a specified network or host

Question 19

What is administrative distance?

Answer 19

A way for the router to select the best route prior to calculating the metric.

Question 20

What type of metric does RIP use?

Answer 20

Hop count (links of all speeds are equal).

Question 21

What type of metric do OSPF and IS-IS use?

Answer 21

Cost (bandwidth based)

Question 22

What type of metric does EIGRP use?

Answer 22

A complex formula based on bandwidth and delay.

Question 23

What is the administrative distance of OSPF?

Answer 23

110

Question 24

What is the administrative distance of static routes?

Answer 24

1

Question 25

What is the administrative distance of directly connected routes?

Answer 25

0

Question 26

What is the administrative distance of EIGRP routes?

Answer 26

90

Question 27

What is the administrative distance of RIP routes?

Answer 27

120

Question 28

What is the administrative distance of IGRP (old EIGRP) routes?

Answer 28

100

Question 29

What is the administrative distance of IS-IS routes?

Answer 29

115

Question 30

Is lower or higher Administrative Distance preferred?

Answer 30

Lower

Question 31

What is the command to change a route’s administrative distance? And why would you do this?

Answer 31

IP Route ‘network’ ‘subnet mask’ ‘next-hop-ip’ ‘AD’

To make one static route more or less preferred over an another.

Question 32

What is a floating static route?

Answer 32

A static route which has been configured to have a higher administrative distance than another. Making it the “backup” route.