Feature Issue on Optical Ethernet
We present a novel proposal for the extension of the currently approved multipoint control protocol (MPCP), as defined in the IEEE 802.3ah standard, clause 64, in the form of two new MPCP messages (extended GATE and extended REPORT), maintaining full backward compatibility with the already-deployed Ethernet passive optical network (EPON) systems and allowing for coexistence with legacy MPCP flow-control messages within the same network structure. Both currently existing logical-link identifier (LLID) assignment systems [namely, one LLID per optical network unit (ONU) and one LLID per queue] are examined in depth, and a missing scenario (one LLID per multiqueue) is discussed. Simulation results conducted using C++ based implementation of standard EPON networks with support for extended GATE-REPORT MPCP data units (DUs) prove that the design assumptions for both new flow-control messages were met to their fullest extent. The eGATE/eREPORT MPCP DUs allow for per-queue scheduling from the central packet controller in the optical line terminal (OLT) at the cost of ONU-based operation, thereby maintaining the benefits of two standard solutions. The obtained simulation results indicate superiority of the proposed IEEE 802.3ah, clause 64 extension in terms of network resource management, bandwidth efficiency, and system setup flexibility.
© 2006 Optical Society of America