Apparatus and method for providing optical channel overhead in optical transport networks

Abstract

A so-called digital “wrapper” is employed in conjunction with an optical channel client signal payload envelope to carry optical channel associated optical channel overhead. That is, the digital wrapper transports optical channel associated optical channel overhead and other monitoring information. This is realized by adding additional capacity, i.e., bandwidth, to the client signal payload envelope. The additional capacity is added “around” the payload envelope and the client signal floats in the payload envelope. This is effected in such a manner that the digital wrapper is independent of the type of client signal that is being transported on the optical channel. Indeed, as such the optical payload envelope is essentially a client optical signal independent, constant bit-rate channel. Moreover, in addition to the digital wrapper providing capacity for the optical channel overhead, it can also be employed to provide a forward error correction capability. Additionally, the added digital wrapper readily provides access for performance monitoring and, especially, access to electrical BER (bit error rate).