1.4

Question 1

Binary to Decimal

Answer 1

Start at 1 on the right and then double to 128

128-64-32-16-8-4-2-1

Write out binary number below the conversion numbers. For every 1 in the binary, bring down the conversion number. Add all the conversion numbers together.

Question 2

Decimal to Binary

Answer 2

Start at 1 on the right and then double to 128 going left

128-64-32-16-8-4-2-1

Starting at the left:
Can the decimal be taken from the conversion number? If yes, place a 1 and determine the difference. If no, place a 0 and bring the decimal down the line. If you placed a 1, bring the difference to the next spot and repeat.

Question 3

Subnet Mask

Answer 3

Used by the local device to determine what subnet it’s on

The subnet mask isn’t usually transmitted across the network so you will have to ask.

Question 4

Default Gateway

Answer 4

Router IP address

The default gateway must be on the same local subnet

Question 5

Loopback Address

Answer 5

Address to yourself

127.0.0.1 through 127.255.255.254

An easy way to self reference and determine if the TCP/IP stack is working properly.

Question 6

Reserved Addresses

Answer 6

Set aside for future use or testing

240.0.0.1 through 255.255.255.254

Question 7

Virtual IP addresses (VIP)

Answer 7

Not associated with a physical network adapter

Virtual machines, internal router address

Question 8

Classful Subnetting

Answer 8

Class A 255.0.0.0 - 8N/24H
Class B 255.255.0.0 - 16N/16H
Class C 255.255.255.0 - 24N/8H

Wasn’t efficient, not used since ‘93
Still used in conversion, “that’s a class C subnet”

Used as a starting point when subnetting

Question 9

Default Subnet Classes

Answer 9

Class A: 1-126, 255.0.0.0
Class B: 128-191, 255.255.0.0
Class C: 192-223, 255.255.255.0

Question 10

Subnet Construction

Answer 10

First IP of a subnet is Network address, all host bits are 0 (0 decimal)

First usable IP is the 1+network address
Last usable is broadcast-1

Last IP of a subnet is a broadcast address, all host bits are 1 (255 decimal)

Question 11

Subnet calculations (Classful)
10.74.222.11

Answer 11

Class A so default subnet mask is 255.0.0.0

10/./74.222.11——Network//Host

Network address 10.0.0.0 (all host bits 0)
First usable 10.0.0.1
Broadcast 10.255.255.255 (all host bits 1)
Last usable 10.255.255.254

Question 12

Subnet Mask and CIDR

Answer 12

255.255.255.0
/24 - 24 bits in the subnet mask
1111111+1111111+1111111+00000000=24

255.255.0.0
/16
11111111+11111111+00000000+00000000=16

11111111+11111111+11111111+11000000=26
/26

Question 13

Subnet Binary to Decimal

Quick Chart

Answer 13

00000000 = 0 (+128)
10000000 = 128 (+64)
11000000 = 192 (+32)
11100000 = 224 (+16)
11110000 = 240
11111000 = 248
11111100 = 252
11111110 = 254
11111111 = 255