1. IPv4 Addresssing
An IP address is four bytes (octets). Each contains eight bits (total of 32 bits in length).
IP addresses are given as dotted decimal notation.
IP address classes A, B, and C differentiate in the numbers of networks and host addresses being utilized by a specific organization.
Class-A is numbered 1through ^8 = 256 networks, ^24 = 16,777,216 addresses Class-B is numbered 128 through ^16 = 65,536 networks, ^16 = 65,536 addresses Class-C is numbered 192 through ^24 = 16,777,216 networks, ^8 = 256 addresses Class-D networks are numbered 224 through 239. Multicast Class-E networks are numbered 240 through 255. Experimental

2. Network & Host address = all 0s: (0.0.0.0) not valid, used during boot
Network address = 0s & Host = #: ( ) a valid host address identifies a host on the current network to other devices.
Network & Host address = all 1s: ( ) this is called a Limited broadcast, where a message will be received by all hosts on a local network.
Network # & all 1s on Host: ( ) this is called a Direct broadcast, where a message is sent to all computers on a remote network. Used to find the MAC address of a known host IP address, Called address resolution (AR)
Network addresses of 127: ( ) loopback or test address

3. Reserved Classes
Special IP addresses are known as Private, which means the hosts on the LAN will never directly communicate with Internet-based hosts.
10.x.x.x through
x.x through
x.x through

4. Subnet masks are also used to subdivide networks.
A subnet mask is used to separate a network number from the host number in an IP address. By Changing the Default Subnet Mask, You Split the Host Number Into a Subnet Number and a Host Number.
Subnet masks are also used to subdivide networks.
1 represents a network and 0 represents a host.

5. Subnet masks examples Class A, B, & C.
= no sub-netting (default mask)
= sub-netting
others:
= no sub-netting
= sub-netting
= no sub-netting
= sub-netting
MASKS Bits

6. Subnetting Classful Subnetting example: Class C
IP Mask
248 or F8 or extra bits for networking
= network default
= host
= subnet Host 10 belongs to
24 bits in network, 5 added subnet mask bits=29 masks
3 bits for hosts = 2^3= 8 addresses, but only 6 hosts
6 hosts + 1 subnet + 1 broadcast = 8 addresses
256/8= 32 subnets with 8 addresses per network

7. Incomplete Class A subnet table
Table 2.1 Class A Subnet Table
Incomplete Class A subnet table
Subnets
Hosts
Mask
Subnet Bits
Host Bits 4
4,194,302 2 22 8
2,097,150 3 21 16
1,048,574 20 32
524,286 5 19 64
262,142 6 18
128
131,070 7 17
256
65,534
512
32,766 9 15
1,024
16,382 10 14
2,048
8,190 11 13
4,096
4,094 12
8,192
2,046
16,384
1,022
32,768
510
65,536
254
131,072
126
262,144 62
524,288 30
1,048,576
2,097,152
4,194,304

8. Incomplete Class B subnet table Incomplete Class C subnet table
Subnets
Hosts
Mask
Subnet Bits
Host Bits 4
16382 2 14 8
8190 3 13 16
4094 12 32
2046 5 11 64
1022 6 10
128
510 7 9
256
254
512
126
1024 62
2048 30
4096
8192
16384
Incomplete Class C subnet table
Subnets
Hosts
Mask
Subnet Bits
Host Bits 4 62 2 6 8 30 3 5 16 14 32 64