1378 IEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 59, NO. 5, MAY 2011 Capacity and Delay Analysis of Next-Generation Passive Optical Networks (NG-PONs) Frank Aurzada, Michael Scheutzow, Martin Reisslein, Senior Member, IEEE, Navid Ghazisaidi, and Martin Maier, Senior Member, IEEE Abstract—Building on the Ethernet Passive Optical Network (EPON) and Gigabit PON (GPON) standards, Next-Generation (NG) PONs () provide increased data rates, split ratios, wave- lengths counts, and fiber lengths, as well as () allow for all-optical integration of access and metro networks. In this paper we provide a comprehensive probabilistic analysis of the capacity (maximum mean packet throughput) and packet delay of subnetworks that can be used to form NG-PONs. Our analysis can cover a wide range of NG-PONs through taking the minimum capacity of the subnetworks forming the NG-PON and weighing the packet delays of the subnetworks. Our numerical and simulation results indicate that our analysis quite accurately characterizes the throughput-delay performance of EPON/GPON tree networks, including networks upgraded with higher data rates and wavelength counts. Our analysis also characterizes the trade-offs and bottlenecks when integrating EPON/GPON tree networks across a metro area with a ring, a Passive Star Coupler (PSC), or an Arrayed Waveguide Grating (AWG) for uniform and non-uniform traffic. To the best of our knowledge, the presented analysis is the first to consider multiple PONs interconnected via a metro network. Index Terms—Metro area network, packet delay, passive optical network, throughput-delay analysis. I. I NTRODUCTION T HE Passive Optical Network (PON) is one of the most widely deployed access networks due to its unique benefits, including transparency against data rate and signal format as well as high data rates and reliability [1]. The two major state-of-the-art PON standards IEEE 802.3ah Ether- net PON (EPON) and ITU-T G.984 Gigabit PON (GPON) consist both of a single upstream wavelength channel and a separate single downstream wavelength channel, whereby both channels are operated with time division multiplexing (TDM). EPON and GPON are expected to coexist for the foreseeable future as they evolve into Next-Generation PONs Paper approved by J. A. Salehi, the Editor for Optical CDMA of the IEEE Communications Society. Manuscript received July 19, 2010; revised October 15, 2010. F. Aurzada and M. Scheutzow are with the Department of Mathemat- ics, Technical University Berlin, 10623 Berlin, Germany (e-mail: {aurzada, ms}@math.tu-berlin.de). M. Reisslein is with the School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287-5706, USA (e-mail: reisslein@asu.edu). N. Ghazisaidi was with the Optical Zeitgeist Laboratory, INRS, University of Québec. He is now with Ericsson Inc., 200 Holger Way, CA 95134, San Jose, USA (e-mail: navid.ghazisaidi@ericsson.com). M. Maier is with the Optical Zeitgeist Laboratory, INRS, University of Québec, Montréal, QC, H5A 1K6, Canada (e-mail: maier@emt.inrs.ca). Supported by the DFG Research Center MATHEON “Mathematics for key technologies” in Berlin. Digital Object Identifier 10.1109/TCOMM.2011.030411.100418 (NG-PONs). NG-PONs are mainly envisioned to () achieve higher performance parameters, e.g., higher bandwidth per subscriber, increased split ratio, and extended maximum reach, than current EPON/GPON architectures [2], and () broaden EPON/GPON functionalities to include, for instance, the con- solidation of optical access, metro, and backhaul networks as well as the support of topologies other than conventional tree structures [3]. In this paper, we evaluate the capacity (maximum mean packet throughput) and packet delay of a wide range of NG- PONs through probabilistic analysis and verifying simulations. More specifically, we analyze the capacity and delay of various subnetworks from which NG-PONs can be formed, thus enabling analytical capacity and delay characterization for a wide range of NG-PONs built from the examined subnetworks. Two important applications for our analysis are: (A) The obtained results provide insight into the performance limitations of candidate NG-PON architectures and thus in- form network operators seeking to upgrade their installed TDM PONs. (B) Neither IEEE 802.3ah EPON nor ITU- T G.984 GPON standardizes a specific dynamic bandwidth allocation (DBA) algorithm. The design of DBA algorithms is left to manufacturers which aim at equipping network operators with programmable DBA algorithms that adapt to new applications and business models and thus make PONs future-proof. Our capacity and delay analysis provides an upper throughput bound and a delay benchmark for polling- based medium access control with gated service [4] which can be used to evaluate the throughput-delay performance of current and future DBA algorithms for NG-PONs. This paper is structured as follows. In the following section, we review related work on the analysis of PON access and metro packet networks. In Section III we give overviews of the EPON and GPON access networks. In Section IV, we present NG-PONs that either () upgrade PONs or () interconnect multiple PONs across a metropolitan area. We conduct the capacity and delay analysis of the subnetworks forming NG-PONs in Section V. In Section VI, we compare numerical throughput-delay results obtained from our analysis with simulations and illustrate the application of our capacity analysis to identify bottlenecks in NG-PONs. We briefly summarize our contributions in Section VII. II. RELATED WORK In this section we briefly review related work on the analysis of passive optical networks and metropolitan area networks. 0090-6778/11$25.00 c ⃝ 2011 IEEE