SDNDefender: A Comprehensive DDoS Defense Mechanism Using Hybrid Approaches over Software Defined Networking

Table 5

Main notations for entropy calculation.

Notation	Description
I	Set of destination IP addresses
Win	The current window
If	The first IP address in the current window
Io	The first subsequent IP address out of the current window
	A destination IP address’s happening probability
	The current window’s entropy value
ef	If’s entropy value under the current window
eo	Io’s entropy value under the current window
	Normal window entropy series
	The mean of es
	The triple standard deviation of es
	Outlier threshold