Patent ID: 8233800

Claim:
A method for providing communications service during an upgrade of an optical communications ring formed from a plurality of nodes, each node operable to transmit and receive a first frame having a number of first time slots equal to N, wherein N is an integer and the first time slots are occupied by data, the method comprising: upgrading a first node in the optical communications ring by increasing a data transmission rate of the first node to an increased rate, the first node coupled to a second node, the second node operable to transmit data at the data transmission rate; at the increased rate, transmitting data in a second frame from the first node to the second node, the second frame having a number of second time slots equal to M, wherein M is an integer greater than N and the data occupies a number of the second time slots of the second frame equal to N; providing at least one identifier to the second node, the at least one identifier identifying the occupied second time slots of the second frame; receiving the second frame at the second node; and detecting, at the second node, the data in the identified second time slots of the second frame according to the at least one identifier.