Microsoft TCP/IP Subnetting Guide

Bit#	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1
Value	32768	16384	8192	4096	2048	1024	512	256	128	64	32	16	8	4	2	1
Hosts	XX	16382	8190	4094	2046	1022	510	254	126	62	30	14	6	2	XX	XX
Bnets		2	6	14	30	62	126		510	1022	2046	4094	8190	16382	XX	XX
Cnets									XX	2	6	14	30	62	XX	XX
Mask	XX	192	224	240	248	252	254	255	XX	192	224	240	248	252	XX	XX

Class	High Bits	1^st Octet
Class A	0	1-126
Class B	10	*28-191
Class C	110	192-223
Class D	1110	Multicst 224-254

*Remember 127 address of the 1^st Octet is reserved for diagnostic loop back.