The first few bits of an IPv6 address which tell a host what kind of address it is.
|0000 0000||Used for things like IPv6 compatible IPv4, loopback and unspecified addresses (1/256th of the address space)|
|001||Aggregatable Global Unicast Addresses (1/8 of the address space)|
|1111 1110 10||Link-Local Unicast Addresses (1/2024 of the address space)|
|1111 1110 11||Site-Local Unicast Addresses (1/2024 of the address space)|
|1111 1111||Multicast Addresses (1/256 of the address space)|
Almost all the other address space is unallocated or reserved.
See IPv6Addressing for more information.
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