Abstract

Recirculation buffer modules combining arrayed waveguide gratings (AWGs), tunable wavelength converters (TWCs), and fiber delay lines (FDLs) have been proposed to bypass the existing switching bottlenecks in massive-scale data centers. Performance studies of such subsystems are devoted exclusively to either the network layer or the physical layer aspects. Network layer studies consider packet drops only due to limited buffering capacity and ignore the critical role of the physical layer in degrading signal quality. Purely physical layer studies, on the other hand, are oblivious to contention-based drops and load transients. As a result, neither approach is able to estimate accurately the performance characteristics of buffer modules as key elements in optical data centers. In this theoretical work, we integrate the network layer and the physical layer effects into a single analysis framework to compare various recirculation buffer module designs in terms of throughput, delay, signal quality, and complexity. We primarily compare the designs in terms of two metrics: maximum operating load and Q-factor degradation impact. Our Monte Carlo simulations indicate that Q-factor degradation has the dominant role in determining the buffer module performance over a wide range of load values, resulting in significant bandwidth limitations. In order to implement optical packet switching in data centers, tradeoffs between physical layer quality requirements and forward error correction (FEC) overheads should be carefully investigated.

© 2012 IEEE

Optical Load-Balancing Tradeoffs in Wavelength-Routing Cloud Data Centers

Houman Rastegarfar, Leslie Ann Rusch, and Alberto Leon-Garcia
J. Opt. Commun. Netw. 7(4) 286-300 (2015)

Analysis of Large-Scale Multi-Stage All-Optical Packet Switching Routers

Q. Xu, H. Rastegarfar, Y. Ben M’Sallem, A. Leon-Garcia, S. LaRochelle, and L. A. Rusch
J. Opt. Commun. Netw. 4(5) 412-425 (2012)

An integrated recirculating optical buffer

Hyundai Park, John P. Mack, Daniel J. Blumenthal, and John E. Bowers
Opt. Express 16(15) 11124-11131 (2008)

High-port low-latency optical switch architecture with optical feed-forward buffering for 256-node disaggregated data centers

Nikos Terzenidis, Miltiadis Moralis-Pegios, George Mourgias-Alexandris, Konstantinos Vyrsokinos, and Nikos Pleros
Opt. Express 26(7) 8756-8766 (2018)

Performance of an optical packet switch with fixed wavelength converter arrays under bursty traffic

Junjie Yang, Fenghong Chu, and Jian Lv
Appl. Opt. 48(26) 4885-4892 (2009)