Efficient and Agile 1+N Protection

This paper introduces an efficient implementation of the network coding-based 1+N protection. The strategy provides proactive protection to N link-disjoint full-duplex connections against single link failures. The implementation is efficient and uses a tree shaped minimum cost protection circuit. The protection circuit carries linear combinations of data units originally transmitted on the working circuits, and these linear combinations can be used to recover data units lost due to failures. This recovery is carried out with the assistance of one node on the protection tree, which is chosen to reduce the recovery time. This protection technique requires the same amount of protection resources used by 1:N protection, where the protection circuit is link disjoint from the protected connections. The paper also makes other contributions. It introduces an Integer Linear Program (ILP) formulation to evaluate the cost of protection using this technique, and compares it to the cost of 1+1 protection. The comparison shows that a significant saving in cost can be achieved, while recovering from failures within a short time. The performance of this scheme is further evaluated using an OPNET-based simulation, where it was shown that the recovery time conforms to acceptable industry standards. Availability analysis is also conducted.