Realization of the stream comparison mechanism in a CSMA/CD type multimode passive optical network node — algorithm

With optical elements getting cheaper almost on a everyday, the common usage of the fully optical network in local environment is only a matter of a rather short time. In order to simplify such a network construction and to reduce its cost, the so called passive optical networks (PON) can be used. The most interesting type of such networks are PONs with symmetrical access of all nodes to the network resources (like in copper Ethernet). Symmetrical PON requires CSMA/CD collision detection mechanism, which is not easy for implementation in optical networks. In the paper we describe the hardware and software structure of the node used in a symmetrical PON network. For collision detection a comparison of streams mechanism is used.