Week 10

Question 1

When encountering an IPv4-only router, an IPv6 datagram is dropped (T/F)

Answer 1

False

Question 2

When encountering an IPv4-only router, an IPv6 datagram is _____ an IPv4 datagram, with the _______ as its destination

Answer 2

encapsulated in, next in line IPv6 router

Question 3

::ffff:ffff:fffff is a valid prefered format IPv6 address (T/F)

Answer 3

False

Question 4

The method by which a MAC protocol coordinates access to a broadcast medium to prevent and/or reduce collisions is most commonly called:

Answer 4

multiple access

Question 5

A network with a ____ topology must terminate the endpointe, but with a ______ topology they are connected so there is no endpoint

Answer 5

bus, ring

Question 6

Which are functions of the Ethernet preamble?

Answer 6

Start signal, Circuit wake-up, Clock synchronization

Question 7

A multiple access scheme which listens to the channel to make sure it is empty prior to transmitting is called:

Answer 7

Carrier sense protocol

Question 8

A multiple access scheme which uses a master node to poll each slave node and control who has permision to transmit at any given time is called:

Answer 8

“Taking Turns” protocol

Question 9

On the sending or receiving host, most of the protocol tasks “below” the application layer of the protocol stack (data encapsulation, IP addressing, etc.) are handled by

Answer 9

the network interface controller (NIC)

Question 10

MAC addresses are redundant because of IP addresses

Answer 10

False

Question 11

Most modern Ethernet LANs use a ____ topology

Answer 11

star

Question 12

For a 10 Mbps link, 100 bit times is 0.1ms (T/F)

Answer 12

False

Question 13

If an Ethernet sender senses a clear channel, and begins transmission, but shortly thereafter detects a collision, it will…

Answer 13

Terminate transmission and enter an exponential backoff

Question 14

For a 10Mbps link, 1000 bit times is 0.1ms (T/F)

Answer 14

True

Question 15

When a mobile unit moves from a home or foreign agent to another foreign agent, the new agent must assign….

Answer 15

a new “Care of” address to the mobile unit

Question 16

Which of the following are major issues that must be handled in wireless networks, check all that apply

Answer 16

Hosts may frequently move from one network to another
Multi path propagation when radio signals bounce off obstacles
Obstacles that block radio signals
Radio waves are more succeptible to interference than signals carried on cable
the “hidden node” problem

Question 17

In one type of wireless network, hosts communicate directly with other hosts that are within range. This communication model forms a “grid” called a(n)

Answer 17

ad-hoc network

Question 18

Which of the following are used in a wireless network such as 802.11n?

Answer 18

Reservation system with RTS and CTS
Collision Avoidance
Carrier Sense Multiple Access
Exponential Back-off / retry for collision resolution

Question 19

When an organization establishes a network security policy, which of the following should be considered?

Answer 19

The cost of installing “secure” systems
The cost of damage control after various types of security breaches
The value of the information that is stored or transmitted by the site

Question 20

Given an encryption scheme that uses encrypt(m) to encrypt message m and uses decrypt(c) to get back the original message. What must be true?

Answer 20

decrypt(encrypt(m)) = m

Question 21

When using an RSA algorithm to construct private and public keys for a public key encryption system, choose prime numbers p and q and then calculate n = pq, z=(p-1)(q-1) Then choose e and d to create the public key and the private key. Suppose that p = 5 and 1 = 11. Which of the following values will work for d and e?

Answer 21

e = 7, d = 63