# Introducing the TCP/IP Internet Layer. IPv4 Addressing, and Subnets Flashcards

At which layer of the TCP/IP stack does IP operate?

A. application layer

B. transport layer

C. internet layer

D. link layer

C. internet layer

Which number system is the foundation of all computer operations?

A. binary

B. decimal

C. ternary

D. hexadecimal

A. binary

Which option is the decimal representation of 10000000?

A. 64

B. 256

C. 128

D. 1

C. 128

What is the binary equivalent of the decimal number 183?

A. 10110011

B. 10110111

C. 11010111

D. 11001001

B. 10110111

How many bits are contained in an IPv4 address?

A. 16 bits

B. 32 bits

C. 64 bits

D. 128 bits

B. 32 bits

What does the TTL value (in the TTL field) represent?

A. The TTL value describes the length of a packet.

B. The TTL value limits the lifetime of a packet.

C. The TTL value describes the length of the header.

D. The TTL value indicates where a specific fragment belongs.

B. The TTL value limits the lifetime of a packet.

Which IPv4 address class is dedicated for multicast?

A. Class A

B. Class B

C. Class C

D. Class D

E. Class E

D. Class D

You have a host 192.168.50.2/24. What is its network address?

A. 192.168.0.0

B. 192.168.50.0

C. 192.0.0.0

D. 255.255.255.0

B. 192.168.50.0

What is a possible problem within a broadcast domain?

A. Larger amounts of broadcast traffic consume resources.

B. It relies on IP addresses for packet delivery.

C. Larger amounts of unicast traffic consume resources.

D. Unicast communication is not possible.

A. Larger amounts of broadcast traffic consume resources.

How many host addresses can be used in a network with a /24 mask that has not been subnetted?

A. 253

B. 254

C. 255

D. 256

B. 254

By borrowing three host bits, how many subnets are created?

A. 10

B. 8

C. 16

D. 32

B. 8

The correct answer is “8.” To determine how many subnets are created by borrowing a given number of bits, count the bits by powers of two. Starting with the far-left bit, begin with 2 (21) and increase by powers of two. Borrowing one host bit enables you to create 2 subnets, borrowing 2 bits gives you 4 subnets, and borrowing 3 bits give you 8 subnets.

You have been assigned a /24 network address. A coworker has requested that you create 10 subnets that can support 10 hosts per network. Which subnet mask should you use?

A. 255.255.255.0

B. 255.255.255.224

C. 255.255.255.240

D. 255.255.255.248

C. 255.255.255.240

The correct answer is “255.255.255.240.” To create 10 subnets, you had to borrow four 4 bits from the fourth octet. The sum of the values of those bits is 240, so you must use the subnet mask 255.255.255.240.

You have subnetted your 192.168.36.0 network address with a 255.255.255.224 mask. How many subnets are available?

A. 16

B. 8

C. 10

D. 32

B. 8

The correct answer is “8.” There are 8 usable subnets and 30 hosts per subnet. The value of 224 in the subnet mask tells you that three host bits were borrowed from the fourth octet for subnetting. To determine how many subnets are created by borrowing 3 bits, count the bits by powers of two, starting with the far-left bit. Begin with 2 and increase by powers of two. To determine how many valid host addresses are available, count the five remaining host bits by powers of two, starting with the far-right bit. Begin with 2 and increase by powers of two, then subtract two.

You have been assigned the network 172.16.0.0/16. You need to establish 13 subnets. What is the new subnet mask in the decimal form?

A. 255.255.240.0

B. 255.255.248.0

C. 255.255.224.0

D. 255.255.252.0

A. 255.255.240.0

The correct answer is “255.255.240.0.” To get 13 subnets, you must borrow 4 host bits from the third octet. If you add the values of those 4 bits, you get the decimal number 240, so the new subnet mask is 255.255.240.0.

A large company has a /8 network but needs to subnet it into 1000 subnets. Which subnet mask segments the /8 network and provides the maximum number of hosts per subnet?

A. 255.255.240.0.

B. 255.255.224.0.

C. 255.255.128.0.

D. 255.255.192.0.

D. 255.255.192.0.

The correct answer is “255.255.192.0.” To subnet a /8 network, you must begin borrowing host bits from the second octet. To determine how many bits to borrow to create 1000 subnets, count the bits by powers of two, starting with the far-left bit. Begin with 2 and increase by powers of two. Borrowing one host bit enables you to create two subnets, borrowing 2 bits gives you four subnets, and so on. You will discover that borrowing all the bits from the second octet and 2 bits from the third octet creates 1024 subnets. If you add the values of all 8 bits in the second octet, you get 255, so the subnet mask for that octet is 255. If you add the values of the 2 bits that you borrowed in the third octet, you get 192. Therefore, the subnet mask that segments the /8 network and provides the maximum number of hosts per subnet is 255.255.192.0.

A company currently has a network range of 192.168.54.0/24. The company wants to subnet this range into 4 subnets, each supporting at least 30 users. Which subnet mask would you recommend?

A. 255.255.255.224

B. 255.255.255.128

C. 255.255.255.240

D. 255.255.255.192

D. 255.255.255.192

Which subnet mask would limit the number of hosts on any given subnet to 2046?

A. 255.248.0.0

B. 255.255.240.0

C. 255.255.248.0

D. 255.255.252.0

C. 255.255.248.0

The correct answer is “255.255.248.0.” Counting host bits by powers of two from right to left indicates that 11 bits are needed to allow for 2046 hosts per subnet (211 = 2048; 2048 – 2 = 2046). Using 11 bits for host addresses means that the first 21 bits of the 32-bit subnet mask are turned on. This way, the subnet mask is 11111111.11111111.11111000.00000000, or 255.255.248.0. The subnet masks 255.248.0.0 and 255.255.240.0 also allow 2046 hosts per subnet, but only the 255.255.248.0 mask limits the number of hosts per subnet to 2046.