Abstract: Extra traffic paths are provided in a communication network including at least two protection channels associated to respective transmission channels. Each protection channel admits an active state for carrying, in the presence of a failure in the associated transmission channel, traffic to be carried by the associated transmission channel, and a stand-by state, wherein the protection channel is adapted to carry extra traffic. The protection channels are run in a sub-network connection protection scheme, whereby one of the protection channels in its stand-by state is adapted to ensure recovery of extra traffic carried by the other protection channel while the other protection channel is switched to its active state or is subject to failure.

Abstract: A method of designing a transport network having a plurality of network elements and a plurality of connections between the network elements by (a) defining a first network configuration and at least one alternative network configuration for the same transport network; (b) calculating for each network configuration, a probability function representing, for each maximum number of routable flows, the probability of routing such a number of flows in the network configuration currently considered; (c) calculating for each network configuration, a unit-cost-per-flow function calculated as the ratio between a sum of the costs relative to the network elements of the network configuration currently considered and the probability function; and (d) comparing the unit-cost-per-flow functions of the network configurations considered, for choosing a network configuration having a lowest unit-cost-per-flow value.

Abstract: Extra traffic paths are provided in a communication network including at least two protection channels associated to respective transmission channels. Each protection channel admits an active state for carrying, in the presence of a failure in the associated transmission channel, traffic to be carried by the associated transmission channel, and a stand-by state, wherein the protection channel is adapted to carry extra traffic. The protection channels are run in a sub-network connection protection scheme, whereby one of the protection channels in its stand-by state is adapted to ensure recovery of extra traffic carried by the other protection channel while the other protection channel is switched to its active state or is subject to failure.

Abstract: A method of designing a transport network having a plurality of network elements and a plurality of connections between the network elements by (a) defining a first network configuration and at least one alternative network configuration for the same transport network; (b) calculating for each network configuration, a probability function representing, for each maximum number of routable flows, the probability of routing such a number of flows in the network configuration currently considered; (c) calculating for each network configuration, a unit-cost-per-flow function calculated as the ratio between a sum of the costs relative to the network elements of the network configuration currently considered and the probability function; and (d) comparing the unit-cost-per-flow functions of the network configurations considered, for choosing a network configuration having a lowest unit-cost-per-flow value.