By Karthik Sundaresan, CableLabs; Evariste Some, CableLabs, & University of Colorado, Boulder
HFC/DOCSIS networks are the most widely deployed technology for delivering Internet data services to the consumers. A passive optical network is another option for access technology deployed by operators using EPON, or GPON technology.
One of the performance questions which many in the operator community want to understand is the latency performance of each type of technology and how they compare. We setup a 10GEPON and XGSPON systems in our labs at CableLabs. We ran speed and latency benchmarks on these types of networks in a lab environment and compared the latencies that we get under a variety of conditions. DOCSIS has various options and configurations (D3.0 SC-QAM channels, D3.1 OFDM/OFDMA channels, AQM, LLD etc., while PON has various flavors: 10G-EPON, XGSPON etc. and configurations as well). This paper will give us a better understanding of the efficiencies and the latencies of each of these technology options and the tradeoffs this entails. Based on time constraints during lab testing, this paper is focused primarily on the PON latencies, with some limited testing on DOCSIS systems and a more complete testing and analysis will be part of future work. This paper will give a brief overview of each technology and its evolution and bring out a theoretical comparison of the latency characteristics of each type of technology and mainly reports on the lab testing results for each technology under different operating and load conditions.