- IPv6 address contains 16-bit numbers
- each double-byte expressed as 4 hex digits
- E.g., binary address:
0010 0000 0000 0001 : 0000 1101 1011 1000 : 0000 0000 0000 0000 : 0000 0000 0000 0000 : 0000 1010 1011 1100 : 0000 0000 0000 0000 : 1101 1110 1111 0000 : 0001 0010 0011 0100- hex notation:
2001:0db8:0000:0000:0abc:0000:def0:1234
- canonical notation
- leading 0s in a double byte can be ignored
- one contiguous series of 0s can be replaced by a double colon
2001:db8::abc:0:def0:1234- can only use double colon once
- when IPv6 is used as part of URL, it must be contained within brackets
- because both formats use colon delimiters to mean different things