Provision of connection-specific availability guarantees in communication networks

The current trend is that the traffic from all services and users is carried by the same backbone network, irrespective of inherent or peculiar quality of service (QoS) requirements. This is also the case for dependability requirements like availability. To provide a service acceptable for users and services with high availability requirements, protection techniques are applied. However, the relation between an availability requirement and a given protection scheme is not direct, since it also depends on the characteristics of the network elements, the topology, the length of the paths, etc. Special care must therefore be taken to provide the desired availability level to each connection in a cost-efficient manner. This paper introduces the concept of protection pattern which is more flexible than segment protection or path protection and includes these schemes as special cases. Next, it presents a fully distributed path management system capable of finding a suitable protection pattern for each connection based on its availability requirement. The system is based on swarm intelligence, which is a general concept which has been shown to provide promising results when applied to network and operational management. The system is implemented in an NS-2 based simulator and tested on a 37-node topology. The simulation results show that the system is flexible and capable of meeting the availability requirements in a cost-efficient manner.