A guideline for realizing the vision of autonomic networking: Implementing self-adaptive routing on top of OSPF
Autonomicity, realized through control loop structures operating within network devices and the network as a whole, is an enabler for advanced and enriched self-manageability of communication systems. Unfortunately, very little practical knowledge is currently available that would guide a network engineer through realizing this ambitious vision. In this survey, we intend to fill this gap by providing a practical guideline for building truly autonomic systems. Our main motivation is the recognition that it is not necessary to rebuild the whole network infrastructure out of piecemeal-designed, autonomic-aware protocol components. Instead, the framework of Autonomic Networking is broad enough to accommodate many of, if not all, existing off-the-shelf network technologies. This is because a sophisticated network protocol machinery is usually a quite capable self-managing entity in itself, complete with all the basic components of an autonomic networking element, like embedded control loops, decision-making modules, distributed knowledge repositories, etc. What remained to be done to achieve the desired autonomic behavior is to open up of some of these intrinsic control loops and incorporate them into external decision making logics. We demonstrate this idea on the example of building advanced self-adaptive routing mechanisms on top of OSPF. First, we present a generic framework for autonomic networks, designed to integrate well-tested, legacy network technology and modern, inherently autonomic-aware functionality into a single feature-rich self-managing infrastructure. Then, we cast an illustrious legacy network technology, the Open Shortest Path First (OSPF) routing protocol, in this framework, we identify the control loops intrinsic to it, and we describe the way these can be incorporated into higher level control loops. Finally, we demonstrate this design process through two illustrative case studies, namely, adding risk-awareness and autonomic routing resilience to the OSPF routing protocol.