Sara Abbasvand ¹, Seyyed Nasser Seyyed Hashemi ², Shahram Jamali ³

Affiliations
1 Department of Computer Engineering, Tabriz Branch, Islamic Azad University, Tabriz, IR
2 Young Researchers Club, Ardabil Branch, Islamic Azad University, Ardabil, IR
3 Department of Computer Engineering, Mohaghegh Ardabili University, Ardabil, IR

Abstract

Connection Management phase of TCP is susceptible to a classic attack that is called SYN-flooding. In this attack, source sends many SYN packets to the victim computer, but does not complete three-way handshaking algorithms. This quickly consumes the resources allocated for communication in the under attack system and hence prevents it from serving other connection requests. This attack causes the victim host to populate its backlog queue with forged TCP connections. In other words it increases the number of legal connections rejected due to limited buffer space. In this paper, the under attack system are modeled by using queuing theory and then a game theoretic approach is employed to defend against SYNflooding attacks. The simulation results show that the proposed defense mechanism improves performance of the under attack system in terms of the ration of blocked connections and the buffer space occupied by attack requests.

Keywords

DoS, Game Theory, SYN-flooding Attacks, TCP

Full Text

   

Shahram Jamali ¹, Bita Alipasandi ², Vahid Rafe ³

Affiliations
1 Computer Engineering Department, University of Mohaghegh Ardabili, IR
2 Department of Computer Engineering, Zanjan Branch, Islamic Azad University, Zanjan, IR
3 Department of Computer Engineering, Malayer Branch, Islamic Azad University, Malayer, IR

Abstract

Active Queue Management (AQM) plays an important role in the Internet congestion control. Random Early Detection (RED) is the most popular active queue management algorithm that is used in the in Internet routers. The effectiveness of RED algorithm highly depends on appropriate setting of its parameters. Moreover, RED uses only the average queue length as a congestion meter to trigger packet dropping as a congestion feedback. Since the average queue length considers only long-term behavior of any queue, this approach fails to see instantaneous changes of the queue and hence its reaction is not fast enough. This paper inspires from the economic principles to design a new congestion control algorithm. This algorithm, called ECORED, enhances the network performance by dynamically tuning of RED's parameters. ECORED introduces two meters i.e. queue length growth velocity and drop rate velocity to measure the congestion level and produce appropriate congestion feedbacks. Based on extensive simulations conducted using Network Simulator-2 (ns-2), we show that ECORED algorithm reduces the packet loss rate and achieves high utilization in compare with RED, ARED and NLRED.

Keywords

Active Queue Management, Average Queue Size, Congestion Control, Dropped Packets, Random Early Detection, Utilization

Full Text