Subnet

Subnet(a.k.a. subnetwork)이란, IP Address를 네트워크 ID와 호스트 ID로 논리적으로 구분해서 큰 네트워크를 작게 나눈 네트워크를 말한다.

subnet (앞에서부터 이진수의 몇 비트가 고정인지)	subnet mask (앞에서부터 1이 연속으로 나와야 함)	Host의 수	비고
/1	128.0.0.0	2,147,483,648
생략
/8	255.0.0.0	16,777,216	A Class Default Subnet Mask
/9	255.128.0.0	8,388,608	A Class Subnet Mask
/10	255.192.0.0	4,194,304	A Class Subnet Mask
/11	255.224.0.0	2,097,152	A Class Subnet Mask
/12	255.240.0.0	1,048,576	A Class Subnet Mask
/13	255.248.0.0	524,288	A Class Subnet Mask
/14	255.252.0.0	262,144	A Class Subnet Mask
/15	255.254.0.0	131,072	A Class Subnet Mask
/16	255.255.0.0	65,536	B Class Default Subnet Mask
/17	255.255.128.0	32,768	B Class Subnet Mask
/18	255.255.192.0	16,384	B Class Subnet Mask
/19	255.255.224.0	8,192	B Class Subnet Mask
/20	255.255.240.0	4,096	B Class Subnet Mask
/21	255.255.248.0	2,048	B Class Subnet Mask
/22	255.255.252.0	1,024	B Class Subnet Mask
/23	255.255.254.0	512	B Class Subnet Mask
/24	255.255.255.0	256	C Class Default Subnet Mask
/25	255.255.255.128	128	C Class Subnet Mask
/26	255.255.255.192	64	C Class Subnet Mask
/27	255.255.255.224	32	C Class Subnet Mask
/28	255.255.255.240	16	C Class Subnet Mask
/29	255.255.255.248	8	C Class Subnet Mask
/30	255.255.255.252	4	C Class Subnet Mask
/31	255.255.255.254	2	C Class Subnet Mask
/32	255.255.255.255	1	C Class Subnet Mask