Distributed flow detection over multi-path sessions

Recently, there has been great interest in performing flow inspection within devices in the network. Frequently, a session passing through the network is routed through several paths either due to network architecture or due to malicious intent. This paper presents a re-routing layer that enables, for the first time, multi-path flow inspection. At any point in time, each session is inspected by a single inspection device using existing single-path flow inspection algorithms. Session packets that arrive at other devices are forwarded to the designated device. Our scheme takes into account the history of packet arrival among all collaborating devices for optimized re-routing. We show that the proposed mechanism is highly efficient in terms of the storage and communication overhead imposed on the network due to packet re-routing. The per-packet computation overhead at the devices is shown to be minimal and in the order of O (1).