NetFlow is a network monitoring protocol and is a widely used tool in network monitoring. Although it is a powerful application and provides improved network visibility, network planning and network security analysis, it brings some disadvantages.  

NetFlow is not practical with user plane monitoring. NetFlow uses a lot of bandwidth and has a performance impact on the devices where it is implemented therefore sampling packets is used, but sampling reduces network visibility and could prevent teams from uncovering critical security threats or performance issues. Time window based monitoring on the other hand has its focus on subscriber behavior and is effective in analyzing the user plane traffic.

This white paper discusses time window based monitoring and compares it to NetFlow.