Analysis of a WDM packet switch with improved performance under bursty traffic conditions due to tuneable wavelength converters

Abstract

Abstract-For realistic traffic, i.e., bursty traffic patterns, the use of tuneable wavelength converters is recognized as essential for reducing the complexity of photonic wavelength division multiplexing (WDM) packet switches. Results are obtained from an analytical traffic model that includes buffering in the wavelength domain and accounts for bursty traffic. The theoretical model is verified by simulations and from the model we find that higher traffic loads as well as burstiness can be accepted when tuneable wavelength converters are used. Consequently, a larger throughput of the photonic packet switches is obtained and very importantly, this is achieved while keeping the number of gates needed to realize the space switches nearly constant.Index Terms-Optical buffering, optical networks, optical packet switching, traffic analysis, wavelength conversion.

Parallel desynchronized block matching: A feasible scheduling algorithm for the input-buffered wavelength-routed switch

“…Buffering is dimensioned for a negligible packet loss probability. Switch sizes considered are N={2,4} input and output fibers, and n={2, 8,32,64} wavelengths per fiber. Results obtained for higher values of N={6,8}, not included in the paper, do not differ from the ones shown.…”

“…On the other hand, the hardware complexity of the IBWR architecture is much lower than the one for the output buffered proposals. Table I illustrates the cost side of this complexity vs. performance trade-off, for three prominent OPS output buffered architectures: the KEOPS switch [9], the Output-Buffered Wavelength-Routed switch [3] and the space switch [8]. The comparison involves switch fabrics of N input and output fibers, n wavelengths per fiber and M buffer positions.…”

“…In most of the situations, independent Bernoulli sources were considered for each input port. In [8], the performance of the space switch (and thus, applicable to any OB switch) was evaluated, assuming that each input port receives an independent ON-OFF bursty source. Again, dependence among input ports associated with the same input fiber was not considered.…”

Optimal packet scheduling in output-buffered optical switches with limited-range wavelength conversion

“…Several optical switch architectures, along with their buffering schemes, have been proposed in recent years [4] [5] [15] [6] [7] [9]. Packet scheduling in bufferless and buffered optical switches has been studied in the literature, see, for example, [13] and [14].…”

<title>Packet scheduling for WDM fiber delay line buffers in photonic packet switches</title>

“…For instance, optical buffering is achieved by using optical fiber delay lines (FDL) for packet contention resolution. [1][2][3][4][5] Using FDL, packets are stored in different lengths of delay lines, through which the departing times of packets are time-shifted. Another technique used for resolving packet contention is to introduce wavelength conversion on FDL, where the wavelengths of more than two packets contending the same output port are converted to different wavelengths by using tunable wavelength converters.…”