Subnet Mask
The first 16 bits is the location of the Class B IPv4 address network ID based in classful addressing. 16 bit is an expression used for microcomputers with 16-bit microprocessors.
128 Bits. An IPv6 address is made up of 8 fields consisting of 16 bits per field. If you multiply 8 x 16 will get 128 bits. Each field is separated by colons unlike IPv4 which was separated by dotted decimal notation. A good link to go to to see the address and how sub-netting is done is on the related links below.
127.0.0.1 is the loopback address in IP.... or in the (slightly modified) words of Dorthy Gale when she returned from Oz "There's no place like 127.0.0.1"
64 bits
IPV4 uses a 4 byte address, whereas the IPV6 uses a 16 byte address. IPv4 has a possible 4,294,967,296 IP addreses. The IPv6 has over 300,000,000,000,000,000,000,000,000,000,000,000,000 possible address's.
Number 0 is used at the end of an IPv4 address for network identifiers and number 255 is used at end of an IPv4 for broadcast addresses.
The IPv4 address is identical for all hosts in a broadcast domain. The IPv4 addresse varies in length. The IPv4 address is used to forward packets.
16
IP addresses are divided into five IP classes:IP address class AIP address class BIP address class CIP address class DIP address class E
An IPv4 address of 75.76.77.68 is considered a Class A address. A class A address ranges from 1.0.0.0 to 126.0.0.0
IN IPv6 we can find 128bits.