Evaluation of burst/packet loss ratio in a bufferless OBS/OPS network with 1 + X path protection

The importance of avoiding burst/packet loss because of equipment failures, especially for critical-mission services, gives rise to a method known as 1+X path protection in optical networks. This method provides additional protection for premium (including emergency) services than the more common 1+1 path protection. In this letter, we consider a bufferless optical burst switched (OBS)/optical packet switched (OPS) network with two types of users: premium (that receive 1+X protection service) and regular (that do not receive such a service). We propose an analytical method based on Erlang fixed-point approximation to evaluate the burst/packet loss of such OBS/OPS network. We demonstrate numerically the accuracy of the approximation, and also the effect and implications of the proportion of the premium traffic as X increases