subnet mask

Subnet mask

ref _ https://m.blog.naver.com/PostView.nhn?blogId=twers&logNo=50116961114&proxyReferer=https%3A%2F%2Fwww.google.com%2F

IP Addressing and Subnetting for New Users

ref _ https://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/13788-3.html

Network and broadcast address

ref _ http://ladu.htk.tlu.ee/erika/taavi/doc2/network_and_broadcast_address.html