Simultaneous Connections Routing in Wavelength–Space–Wavelength Elastic Optical Switches

Abstract

In this paper, we investigate the three-stage, wavelength–space–wavelength switching fabric architecture for nodes in elastic optical networks. In general, this switching fabric has r input and output switches with wavelength-converting capabilities and one center-stage space switch that does not change the spectrum used by a connection. This architecture is most commonly denoted by the WSW1 (r, n, k) switching network. We focus on this switching fabric serving simultaneous connection routing. Such routing takes place mostly in synchronous packet networks, where packets for switching arrive at the inputs of a switching network at the same time. Until now, only switching fabrics with up to three inputs and outputs have been extensively investigated. Routing in switching fabrics of greater capacity is estimated based on routing in switches with two or three inputs and outputs. We now improve the results for the switching fabrics with four inputs and outputs and use these results to estimate routing in the switching fabric with an arbitrary number of inputs and outputs. We propose six routing algorithms based on matrix decomposition for simultaneous connection routing. For the proposed routing algorithms, we derive criteria under which they always succeed. The proposed routing algorithms allow the construction of nonblocking switching fabrics with a lower number of wavelength converters and the reduction of the overall switching fabric cost.

Simulation Studies of 3-Stage Clos Switching Network with Prioritization Mechanism Used in Flexible Wavelength-Division Multiplexing Network Nodes

“…A more precise characterization of the W-S-W network's structure discloses that the first and third stages are formed with bandwidth-variable waveband-converting switches (BV-WBCSs) (Figure 2) [1,4,16], whereas the second stage employs bandwidth-variable waveband-selective space switches (BV-WBSSSs) (Figure 3) [1,16]. In the network, it was assumed that switches in the first and last stages could modify both the wavelength and the switch output (optical fiber).…”

“…Flexible WDM technology employs the concept of FSUs to designate the unit of bandwidth in the frequency domain. Assigning bandwidth to a data stream flexibly is achieved by utilizing a defined quantity of consecutive FSUs [3][4][5][6][7]. Research on frequency slots in the flexible WDM networks is presented in [8,9], among others.…”

“…Emphasis should be placed on the fact that 3-stage W-S-W (wavelength-space-wavelength) switching networks are among the most commonly utilized structures for switching networks in flexible WDM netorks [4,16].…”

A New Model of the Limited Availability Group with Priorities for Multi-Service Networks

“…These mechanisms have been used for years to describe traffic phenomena occurring in networks and more broadly in multiservice systems. Examples of applications of such mechanisms include those used to shape traffic in multiservice cellular networks [20][21][22][23][24] and in elastic optical networks [8,9,[25][26][27][28][29][30][31][32][33]. In both types of networks, the consequences of introducing a traffic management mechanism can be seen in both the way nodes and the links between them are modeled.…”