Intrusion detection is the process of monitoring the events occurring in a computer system or network and analyzing them for
signs of possible incidents, which are violations or imminent threats of violation of computer security policies, acceptable
use policies, or standard security practices. Intrusion prevention is the process of performing intrusion detection and
attempting to stop detected possible incidents. Intrusion detection and prevention systems (IDPS) are primarily focused on
identifying possible incidents, logging information about them, attempting to stop them, and reporting them to security
administrators. In addition, organizations use IDPSs for other purposes, such as identifying problems with security policies,
documenting existing threats, and deterring individuals from violating security policies. IDPSs have become a necessary
addition to the security infrastructure of nearly every organization. In this paper we discuss the one technology of IDPS
named network behavior analysis system. A network behavior analysis system (NBAS) is basically an IDPS (intrusion
detection and prevention system) technology which examines network traffic to identify threats that generate unusual traffic
flows, such as distributed denial of service (DDoS) attacks, certain forms of malware, and policy violations, In this paper we
provides a detailed discussion of NBA technologies. First, it covers the major components of the NBA technologies and
explains the architectures typically used for deploying the components. It also examines the security capabilities of the
technologies in depth, including the methodologies they use to identify suspicious activity. The rest of the part discusses the
management capabilities of the technologies, including recommendations for implementation and operation