Module 4: Practice Quiz

Question 1

What has the internet topology evolved from and to?

Answer 1

From a hierarchical structure to a flat structure

This reflects changes in how networks are organized and interconnected.

Question 2

In a peering relationship, the traffic exchanged between the two peers must be highlyasymmetricso that there is enough incentive for both parties topeer with each other.

True/False

Answer 2

False

Asymmetry in traffic can motivate peers to maintain their connection.

Question 3

Acustomer-providerrelationship betweenASesis based on a financial settlement, which determines how much thecustomer will pay the provider. The providertakes care of connecting the customernetwork withdestinations found in the provider’s routingtable.The customer pays regardless of the direction of the traffic.

True/False

Answer 3

True

Question 4

There is no incentive for smaller ISPs to peer with each other.

True/False

Answer 4

False

Question 5

Provider ASes have a financial incentive to forward as much of their customers’ traffic as possible.

True/False

Answer 5

True

This is crucial for maintaining revenue in a customer-provider relationship.

Question 6

What is the correct order for an AS to import its routes based on their incentive?

Answer 6

Routes learned from: customers -> peers -> providers

This order reflects the hierarchy of route preference.

Question 7

What is the difference between iBGP and eBGP?

Answer 7

eBGP is established between routers from different ASes; iBGP is between routers in the same AS

This distinction is important for understanding BGP routing.

Question 8

What is the role of IGP-like protocols in relation to AS internal routers?

Answer 8

Establish paths based on specific costs within the AS

This contrasts with iBGP, which focuses on external route dissemination.

Question 9

A router within an AS applies \_____ policies to exclude routes from further consideration.

Answer 9

import

This helps in managing route selection effectively.

Question 10

The LocalPref attribute is used to prefer routes learned through a specific AS for _______ traffic.

Answer 10

Outbound

This attribute plays a key role in route selection.

Question 11

If AS X prefers to route traffic through AS Z over AS Y, what can it do with the LocalPref value?

Answer 11

Assign a higher LocalPref value to routes from Z

This allows AS X to control traffic exit points.

Question 12

What does the MED (Multi-Exit Discriminator) value designate?

Answer 12

Preferred links for Inbound traffic

This is crucial for ASes connected by multiple links.

Question 13

For AS Y to prefer R1 over R2 to forward traffic to AS X, what must R1 have?

Answer 13

A lower MED value

This assumes all other attributes are equal.

Question 14

One of the services offered by IXPs is protection against what type of attacks?

Answer 14

DDoS attacks

This is critical for maintaining network security.

Question 15

Participation of an AS in an IXP is free.

True/False

Answer 15

False

There are typically costs associated with participation.

Question 16

IXPs handle large volumes of traffic.

True/False

Answer 16

True

This is part of their role in the internet ecosystem.

Question 17

One of the reasons why networks choose to peer at IXPs is because critical players in today’s Internet ecosystem often “incentivize” other networks to connect at IXPs.

True/False

Answer 17

True

These incentives can include better connectivity and reduced costs.

Question 18

Private peering PIs do not use the IXP’s _______.

Answer 18

public peering infrastructure

This indicates a more exclusive arrangement.

Question 19

IXPs users may use Route Servers for an additional cost.

True/False

Answer 19

False

This highlights the potential for additional expenses in IXP participation.

Question 20

Route Servers keep track of BGP sessions they maintain with each participant AS through _______.

Answer 20

RIBs

RIBs are essential for managing routing information.

Question 21

\_____ filters are applied to ensure that each member AS only advertises routes that it should advertise.

Answer 21

import

This is vital for maintaining the integrity of route announcements.