Feature Issue on Optical Ethernet (OE)Ethernet passive optical network (EPON) efficiency issues in both upstream and downstream directions are discussed in detail, describing each component of the overall transmission overhead as well as quantifying their effect on the system's performance and comparing them with the other existing passive optical network (PON) access systems, namely, asynchronous transfer mode PON (APON) and generic framing PON (GPON). For EPON, two main transmission overhead groups are defined, namely, Ethernet encapsulation overhead and EPON-specific scheduling overhead. Simulations are performed using the source aggregation algorithm (SAA) to verify the Ethernet encapsulation overhead for various synthetic and measured packet size distributions (PSDs). A SAA based an EPON simulator is used to verify both upstream and downstream overall channel efficiencies. The obtained simulation results closely match the theoretical limits estimated based on the IEEE 802.3ah standard. An estimated throughput of 820 to 900 Mbits/s is available in the upstream direction, whereas in the downstream direction effective throughput ranges from 915 to 935 Mbits/s.
© 2006 Optical Society of AmericaPDF Article