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Appendix B
IP Address
An IP address is a unique 32-bit address assigned to a computer and includes:
• A network ID number identifying a network.
• A host ID number identifying a computer on the network.
All IP addresses have been divided into three smaller groups (classes) A, B and C
•
Class A
addresses have 8-bits of network ID and 24-bits of host ID. They can support
a large number of hosts, approximately 2 = 16,777,216 computers per network.
The IP addresses range in binary from 00000001.xxxxxxxx.xxxxxxxx.xxxxxxxx
to 01111111.xxxxxxxx.xxxxxxxx.xxxxxxxx
The IP addresses range in decimal from 1.x.x.x to 127.x.x.x
Class A network ID’s support a very large number of hosts.
•
Class B
addresses have 16-bits of network ID and 16-bits of host ID. They can
support approximately 2
16
= 65,536 computers per network.
The IP addresses range in binary from 10000000 00000000.xxxxxxxx.xxxxxxxx
to 10111111 11111111.xxxxxxxx.xxxxxxxx
The IP addresses range in decimal from 128.0.x.x to 191.255.xxx.xxx
Class B network ID’s support a medium number of hosts.
•
Class C
addresses have 24-bits of network ID and 8-bits of host ID. They can support
approximately 2
8
= 256 computers per network.
The IP addresses range in binary from 11000000.00000000.00000000.xxxxxxxx
to 11011111.11111111.11111111.xxxxxxxx
The IP addresses range in decimal from 192.0.0.xxx to 223.255.255.xxx
Class C network ID’s support a small number of hosts.
The rest of the addresses are divided into two classes, D and E.
Class D networks
are not assigned to the host. They are used for multicasting.
The address range from 224.x.x.x to 239.x.x.x
Class E
networks are experimental or reserved addresses.
The address range from 240.x.x.x to 247.x.x.x
