The meanings of /32, /48, /64 in IPv6 addresses

ipv6 Address bai trailing /64,/48,/32 refer to ipv6 Prefix length of address du( Prefix , The former 64 or 48 or 32 The address of bit length is the same zhi).

because ipv6 The address is 128 Bit length ( It uses dao16 Base number ), But the agreement stipulates that after 64 Bit is the network interface ID( It can be understood as the only device on the network ID), So the general household ipv6 Distribution is distribution /64 Prefixed (64 A prefix +64 Bit interface ID).

When ipv6 The address is /48 When ,128-48-64=16 position , It's available ip The number is FFFF( Hexadecimal notation , namely 65535), It can be understood as allocable 65535 A family or company .
When ipv6 The address is /32 When ,128-32-64=32 position , That is, available ip The number is FFFFFFFF( About equal to 42.95 Billion ), You can assign 42.95 Billion families or companies

Actually , Just one /64 The prefix address is fast enough for the entire family ( China ) Use (2 Of 64 The total power is 1844 Billion addresses , Even if you remove 100 million words , All of them 1844 Billion ). In order to be more intuitive , Make a comparison : If a person or a device counts a byte (1k=1024 byte ), One /64 The prefix address is fast enough to accommodate

16384PB(1PB=1024T=1024*1024G) An address . The reason why it continues to be divided into /32,/48 these , To facilitate management and narrow the scope of traceability ( Fast fixed point positioning ...)