As a general definition - a network is a broad clustering of IP addresses. Specifically for Sift Science - a Network is defined as the connection that our Machine Learning Models make between users based on multiple factors.

Say two user's are logging in from the same computer - two different email addresses. These user's would share the same IP address, Device Information, and maybe even cookie information. Sift Science would then show the 'Network' of these two users. 

For IP addresses specifically - Sift Science considers all IP addresses matching the first two octets (the first two numbers from 0-255) to be in the same network.

For example, 199.87.82.110 and 199.87.154.12 are both in the 199.87 network.