International Journal of Computer Applications
Intrusion of network which couldn't be analyzed, detected and prevented may make whole network system paralyze while the abnormal detection can prevent it by detecting the known and unknown character of data. Many intrusions aren't composed by single events, but by a series of attack steps in chronological order. Analyzing the order in which events occur can improve the attack detection accuracy and reduce false alarms. Intrusion is a multi step process in which a number of events must occur sequentially in order to launch a successful attack.