?
/16  --		FFFF::
/17  --		FFFF:8000::
/18  --		FFFF:C000::
/19  --		FFFF:E000::
/20  --		FFFF:F000::
/21  --		FFFF:F800::
/22  --		FFFF:FC00::
/23  --		FFFF:FE00::
/24  --		FFFF:FF00::
/32  --		FFFF:FFFF::
/48  --		FFFF:FFFF:FFFF::
/64  --		FFFF:FFFF:FFFF:FFFF::
/80  --		FFFF:FFFF:FFFF:FFFF:FFFF::
/96  --		FFFF:FFFF:FFFF:FFFF:FFFF:FFFF::
/112 --	65536	FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF::
/128 --	1	FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF