Patent ID: 7096275

Claim:
A method of routing traffic between first and second nodes in a network so as to provide protection against network failures, the method comprising the steps of: routing units of traffic on corresponding sets of trunks connected between the first and second nodes such that the traffic is balanced between disjoint paths; and implementing a restoration process for the traffic; the first and second nodes being connected by first and second sets of trunks such that the nodes and sets of trunks form a ring having at least four trunks, the first set of trunks carrying traffic in a given direction from the first node to the second node and being associated with one of an upper portion and a lower portion of the four-trunk ring, the second set of trunks carrying traffic in the given direction from the first node to the second node and being associated with the other of the upper portion and the lower portion of the four-trunk ring, wherein each of the first and second sets of trunks includes a primary trunk and a backup trunk, both the primary trunk and the backup trunk of each of the first and second sets of trunks being configurable to carry traffic in the given direction from the first node to the second node; a given one of the units of traffic comprising a unit of traffic to be transmitted in the given direction from the first node to the second node utilizing one of the upper portion and the lower portion of the four-trunk ring; wherein the first and second nodes are configured to perform, in conjunction with the restoration process for the given unit of traffic, span switching between the primary trunk and the backup trunk of the associated portion of the four-trunk ring.