Current and future multimedia networks require connections under specific quality of service (QoS) constraints which can no longer be provided by the best-effort Internet. Therefore, 'smarter'networks have been proposed in order to cover this need. The cognitive packet network (CPN) is a routing protocol that provides QoS-driven routing and performs self-improvement in a distributed manner, by learning from the experience of special packets, which gather on-line QoS measurements and discover new routes. The CPN was first introduced in 1999 and has been used in several applications since then. Here we provide a comprehensive survey of its variations, applications and experimental performance evaluations.
Smart networks have grown out of the need for stable, reliable, and predictable networks that will guarantee packet delivery under Quality of Service (QoS) constraints. In this article we present a measurement-based admission control algorithm that helps control traffic congestion and guarantee QoS throughout the lifetime of a connection. When a new user requests to enter the network, probe packets are sent from the source to the destination to estimate the impact that the new connection will have on the QoS of both the new and the existing users. The algorithm uses a novel algebra of QoS metrics, inspired by Warshall's algorithm, to look for a path with acceptable QoS values to accommodate the new flow. We describe the underlying mathematical principles and present experimental results obtained by evaluating the method in a large laboratory test-bed operating the Cognitive Packet Network (CPN) protocol.
Reliable networks that provide good service quality are expected to become more crucial in every aspect of communication, especially as the information transferred between network users gets more complex and demanding and as malicious users try to deliberately degrade or altogether deny legitimate network service. The Cognitive Packet Network (CPN) routing protocol provides Quality of Service (QoS) driven routing and performs self-improvement in a distributed manner, by learning from the experience of special packets, which gather on-line QoS measurements and discover new routes. Although CPN is generally very resilient to network changes, it may suffer worse performance during node failures caused by network threats, such as network worms. Here we evaluate the performance of CPN in such crises and compare it with the Open Shortest Path First (OSPF) routing protocol, an industry standard and widely used in Internet Protocol networks. We also improve it by introducing a failure detection element that reduces packet loss and delay during failures. Our experiments were performed in a real networking testbed.
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