8 blocks separated by a colons, e.g.: 2001:0db8:0000:0000:0000:8a2e:0370:7334
•each block have 4 digits.
•each digit can have a value on Base16, between 0 and F. E.g. 0,1,2,3,4,5,6,7,8,9, a,b,c,d,e,f
•allows for 2128 combinations/addresses
0 at the beginning of a block may be skipped. E.g. 2001:0db8:0000:0000:0000:8a2e:0370:7334 becomes 2001:db8:0:8d3:0:8a2e:70:7344
Consecutive blocks of zeros may be skipped and replaced by two colons. E.g. 2001:db8:0:0:0:0:1428:57ab becomes 2001:db8::1428:57ab