The Sky Networks - CIDR CIDR (Classless Inter-Domain Routing) notation rather than the common subnet mask 255.x.x.x when configuring addresses and networks. Refer to the CIDR Subnet Table to find the CIDR
Subnet Mask - Network Encyclopedia
IPv4 - Subnetting
How to configure Subnet mask on Android?
networking - How exactly is a subnet mask used when determining where to send a packet to? - Super User