Extended ECN mechanism to mitigate ECN-based attacks

Abstract

Today, usage of internet is growing exponentially. Congestion detection and avoidance algorithms are the major issues in TCP/IP. Earlier, packet drops are only source of congestion indication, but it leads to loss of throughput. Active Queue Management (AQM) can detect congestion before the queue overflows and informs the end hosts to respond congestion. It allows gateways to drop packets when average queue is greater than maximum threshold and marks the packets otherwise. Explicit Congestion Notification (ECN) mechanism marks the packets when the average queue size is between predefined thresholds and improves the throughput of a network. But it depends on the end hosts to respond to congestion. So there is a possibility of misbehavior by sender to increase its congestion window, even if the receiver correctly signals about congestion. So misbehaving ECN sender flow obtains more throughput than the normal ECN-enabled flows. We present an Extended ECN mechanism that enables a router to mark packets and the receiver to signal congestion to the sender without trusting the sender whether it has responded congestion or not. Our improved mechanism is robust in detection and prevention of this misbehaving sender in network and compatible with ECN and TCP/IP mechanisms.