· Quality of IP Address (Borrowed from the Human & Telecom networks)
1. Identification and Location
2. Same length
3. Network is divided based on the size
· IP Address – 32 bit address
· IP Address has two parts.
1. Location (NID – Network ID)
2. Identification (HID - Host ID)
NETWORK CLASSIFICATIONS
CLASS A :
NID – 8 bits.
HID – 24 bits.
Network ID
There are 8 bits and so - 28 networks are possible = 256 networks. These 0-255 values in first octet are shared among other classes also. We have values ranging in 0-127 for Class A.
Thus Class A can have 1-126 networks.
E.g. 10.0.0.0 is a Class A Network
Host ID
If the hosts IDs are ‘0’ then it represents the Network and not the host. If the hosts IDs are ‘1’ then it represents the Broadcast address for the particular network.
E.g.
ü 10.0.0.0 ----------- Network Address(All HID ‘0’)
ü 10.0.0.1 ----------- First Host IP Address(All HID ‘0’except the least)
ü 10.255.255.254 ----------- Last Host IP Address(All HID ‘1’except the least)
ü
ü 10.255.255.255 ----------- Broadcast IP Address(All HID ‘1’
CLASS B :
NID – 16 bits.
HID – 16 bits.
Network ID:
ü Two bits are reserved for Class B.
ü The other bits can be from 000000 to 111111.
NID has 2 octets out of which two 2 bits are reserved.
216 - 2 = 214 = 16384 networks for Class B.
E.g. 172.16.0.0 is a Class B network.
Host ID
If the hosts IDs are ‘0’ then it represents the Network and not the host. If the hosts IDs are ‘255’ then it represents the Broadcast address for the particular network.
E.g.
ü 170.27.0.0 ----------- Network Address
ü 170.27.0.1 ----------- First Host IP Address
ü 170.27.255.254 ----------- Last Host IP Address
ü 170.27.255.255 ----------- Broadcast IP Address
CLASS C :
Network ID
ü The others can be from 00000 to 11111.
NID has 3 octets out of which two 3 bits are reserved.
224 – 3 = 221 = 2097152 networks for Class C.
E.g. 202.14.0.0 is a Class C network.
Host ID
If the hosts IDs are ‘0’ then it represents the Network and not the host. If the hosts IDs are ‘255’ then it represents the Broadcast address for the particular network.
E.g.
ü 194.21.16.0 ----------- Network Address
ü 194.21.16.1 ----------- First Host IP Address
ü 194.21.16.254 ----------- Last Host IP Address
ü 194.21.16.255 ----------- Broadcast IP Address
Class D: Class D can have 224 – 239 networks. They are used for Multicasting.
Class E: Class E can have 240 – 255 networks. They are used for Research purposes.
Note: From the above given addresses some addresses are reserved for the private networks. They are,
10.0.0.0 --------- A
172.16.0.0 to 172.31.0.0 --------- B
192.168.0.0 to 192.168.255.0 --------- C
Broadcasting:
Broadcast involves delivering a message from one sender to many recipients. This broadcast is 'limited' in that it does not reach every node on the Internet, only nodes on the LAN.
Broadcast address is found by ORing the IP address and the bit complement of the subnet mask.
E.g. : Let 190.16.4.9 be the IP address(Class B network).
The subnet mask for class B network is 255.255.0.0
---bit complement is 0.0.255.255
190.16.4.9 ---- 10111110000100000000010000001001
0.0.255.255 ---- 00000000000000001111111111111111 190.16.255.255 ---- 10111110000100001111111111111111
