IPv4 Addressing Scheme Flashcards

Class A

• Range: 0.0.0.0 to 127.255.255.255
• Private IP range: 10.0.0.0 to 10.255.255.255
• Loopback range: 127.0.0.0 to 127.255.255.255
• 8 bits for network address and 24 bits for host address
• First octet pattern: 0xxx.xxx, indicating Class A
• Usable Network ID bits: 7 (8-1)
• Possible Network IDs: 126 (2^7 - 2)
• Possible Host IDs: 16,277,214 (2^24 - 2)
• Reserved addresses: 0 and 127 cannot be used for regular IP addresses
• Default subnet mask: 255.0.0.0

Class B

• Range: 128.0.0.0 to 191.255.255.255
• Private IP range: 172.16.0.0 to 172.31.255.255
• Automatic Private IP Addressing (APIPA): 169.254.0.0 to 169.254.255.255
• First octet pattern: 10xx.xxx, indicating Class B
• Usable Network ID bits: 14 (16-2)
• Possible Network IDs: 16,384 (2^14)
• Possible Host IDs: 65,534 (2^16 - 2)
• Default subnet mask: 255.255.0.0

Class C

• Range: 192.0.0.0 to 223.255.255.255
• Private IP range: 192.168.0.0 to 192.168.255.255
• First octet pattern: 110x.xxx, indicating Class C
• Usable Network ID bits: 21 (24-3)
• Possible Network IDs: 2,097,152 (2^21)
• Possible Host IDs: 254 (2^8 - 2)
• Default subnet mask: 255.255.255.0

Class D

• Range: 224.0.0.0 to 230.43.160.48
• Reserved for IP multicast addresses
• Default subnet mask: 239.255.255.255

Class E

• Range: 240.0.0.0 to 250.217.39.190
• Addresses set aside for research and experimentation
• Default subnet mask: 255.255.255.255

Private IP Addresses

• Class A: 10.0.0.0 to 10.255.255.255
• Class B: 172.16.0.0 to 172.31.255.255
• Class C: 192.168.0.0 to 192.168.255.255

IPv4 Address Space Limitations

• 32-bit IP address space allows approx. 4.295 billion unique addresses (2^32)
• Fixed classes result in unavailable node addresses between classes or subnets
• Limited number of node addresses leads to inefficient IP address allocation
• Class A and Class B IP addresses are becoming depleted
• Unassigned and unused addresses within existing Class A and Class B blocks exist