Networking - IP addressing: Classful addressing

Class A addresses

0 // 0000000 // 00000000 00000000 00000000 to 0 // 0000000 // 00000000 00000000 00000001 to 0 // 0000000 // 00000000 00000000 00000010 to -- 0 // 1111111 // 11111111 11111111 11111111. The IP address range for Class A is 0.0.0.0 to 127.255.255.255.

Class B addresses

1 // 0 // 00000000 00000000 // 00000000 00000000 to 1 // 0 // 00000000 00000000 // 00000000 00000001 to 1 // 0 // 00000000 00000000 // 00000000 00000010 to -- 1 // 0 // 11111111 11111111 // 11111111 11111111. The IP address range for Class B is 128.0.0.0 to 191.255.255.255.

Class C addresses

1 // 1 // 0 // 00000000 00000000 00000 // 00000000 to 1 // 1 // 0 // 00000000 00000000 00000 // 00000001 to 1 // 1 // 0 // 00000000 00000000 00000 // 00000010 to -- 1 // 1 // 0 // 11111111 11111111 11111 // 11111111 to The IP address range for Class C is 192.0.0.0 to 223.255.255.255.

Class D addresses

1 // 1 // 1 // 0 // 00000000 00000000 00000000 0000 to 1 // 1 // 1 // 0 // 00000000 00000000 00000000 0001 to 1 // 1 // 1 // 0 // 00000000 00000000 00000000 0010 to -- 1 // 1 // 1 // 0 // 11111111 11111111 11111111 1111. The IP address range for Class D is 224.0.0.0 to 239.255.255.255.

Example of a Class A Network

103.0.0.0: Network address 103.0.0.1 to 103.255.255.254: All addresses to be assigned hosts. 103.255.255.255: Broadcast address

IP address format

Format of each class of IP address is divided into three sections: reserved bits, network bits and host (network device) bits.

IPv4 addresses

IPv4 (Internet Protocol Version 4) addresses are divided into 5 classes: Class A, Class B, Class C, Class D, Class E

Class A format

Reserved "0" (1 bit)//Network (7 bits)//Host (24bits) The value of the reserved bit is always zero in class A.

Class E format

Reserved "1" (1 bit) // Reserved "1" (1 bit) // Reserved "1" (1 bit) // Reserved "1" (1 bit) // Reserved "0" The 5 reserved bits are always 1 1 1 1 0.

Maximum number of networks that can be assigned to hosts in a Class A.

To compute the number of class A networks, use the following formula: Number of networks = 2^(Number of network bits in address class) =2^7 =128

Maximum number of addresses that can be assigned to hosts in a Class B network

What is the maximum number of addresses that can be assigned to hosts in a class B network? =(2^16)-2 = 65,534

Maximum number of networks that can be assigned to hosts in a Class B.

What is the number of Class B networks? =2^14 = 16,384 Class B addresses are used for medium to large networks * For example, a large college campus can be assigned class B addresses in the range of 145.108.0.0 to 145.108.255.255 * Class B IP addresses 172.16.0.0 to 172.16.31.255 are reserved for private addressing

Maximum number of networks that can be assigned to hosts in a Class C.

What is the number of Class C networks? = 2^(Number of network bits in address class) = 2^21= 2,097,152 * Class C addresses are for small networks For example, a small business can be assigned class C addresses in the range of 202.17.5.0 to 202.17.5.25

Maximum number of addresses that can be assigned to hosts in a Class C network

What is the number of addresses that can be assigned to hosts in a class C network? = 2^(Number of host bits in address class) - 2 = (2^8)-2=254

Class E addresses

1 // 1 // 1 // 1 // 0 // 00000000 00000000 00000000 000 to 1 // 1 // 1 // 1 // 0 // 00000000 00000000 00000000 001 1 // 1 // 1 // 1 // 0 // 00000000 00000000 00000000 010 -- 1 // 1 // 1 // 1 // 0 // 11111111 11111111 11111111 111 The IP address range for Class E is 240.0.0.0 to 255.255.255.

Maximum number of addresses that can be assigned to hosts in a Class D network

Number of Class D addresses = 2^(Number of bits used for multicast) = 2^ 228 = 268,435,456 Link to a video about multicast: http://www.cisco.com/c/en/us/products/ios-nx-os-software/ip-multicast/index.html

Class C format

Reserved "1" (1 bit)// Reserved "1" (1 bit) // Reserved "0" // Network (21 bits) //Host (8 bits) The 3 reserved bits are always 1 1 0.

Maximum number of addresses that can be assigned to hosts in a class E network.

Number of Class E addresses = 2^(Number of bits for future use) = 2^227 = 134,217,728 * Class E addresses are assigned for experimental use by research organizations. * Class E addresses are not used in the internet. * A ping to a class E address will fail. Try pinging the Class E address 242.36.83.172

Maximum number of addresses that can be assigned to hosts in a Class A network

Number of addresses that can be assigned to hosts = 2^(Number of host bits in address class) - 2 One address is used as a network address and one address is used as a broadcast address. Thus, the reason to subtract 2 =(2^24)-2 = 16,777,214

Class D format

Reserved "1" (1 bit) // Reserved "1" (1 bit) // Reserved "1" (1 bit) // Reserved "0" // Multicast (28 bits) The 4 reserved bits are always 1110. A multicast address is used to send a message simultaneously to a specific group of hosts on a network. Class A, B and C addresses are unicast addresses used to communicate with a single host.

Class B format

Reserved "1" (1 bit)// Reserved "0" (1 bit) // Network (14 bits)//Host (16bits) The value of the two reserved bits are always one and zero in class B.