IP protection and restoration

Protection and restoration together connote an additional layer of reliability, availability and integrity wherever they are applied. Protection ensures that the desired service will not be permanently disrupted in the event of a component failure. Restoration ensures the desired service will be returned following a component failure. For many years, IP has provided a form of protection and restoration by enabling packets to be dynamically rerouted around link or node failures. Coupled with TCP´s reliable transport service, it is easy to see how TCP/IP based networking has achieved a reputation for robustness. The temporal dimension to this IP rerouting mechanism could, however, limit its usefulness for applications with real-time service-level requirements. It takes an IP network some time (usually tens of seconds) to detect a failure, propagate the information to other routers around the network, and then have each router compute a new path. The paper considers how efforts are under way in the research and vendor communities to develop faster and more robust protection and restoration mechanisms for IP networks