What are the special cases and consideration in the IPv4 class-based system?

What will be an ideal response?

There are special cases and considerations in the IPv4 class-based system:
* If the first octet is zero, the remaining octets identify local machines on the same network as the computer sending data. The special IPv4 address 0.0.0.0 is used in routing logic to represent "all other computers."
* A first octet value of 127 identifies a destination that is local to the computer sending data. The address in this range that is commonly seen is 127.0.0.1, or the loopback address. Data sent to the loopback address will return to the computer that sent it and will not appear on the actual network.
* A first octet identifying a class D address represents a multicast address. Computers that belong to the same multicast group will have the same multicast address assigned to them. Data sent to that multicast address will attempt to deliver copies of the data to all multicast members with the same address. Class D addresses are not used to identify a single host computer with a unique IPv4 address.
* A first octet identifying a class E address is reserved for future use and special purposes. Class E addresses are not used to identify a single host computer with a unique IPv4 address. The special IPv4 address 255.255.255.255 is used as a broadcast address that represents the destination "all computers in this network." Data sent to this broadcast address cannot leave the local network through a router.