Dual stage optical multi-protocol label switching using out-of-band wavelength and code properties

John Daniel Medrano, University of Texas at El Paso


Time Division Multiplexing (TDM), Wavelength Division Multiplexing (WDM), and Code Division Multiple Access (CDMA) techniques have been implemented in optical point-to-point communication links to exploit the ultra-wide bandwidth available in fiber optics. Current operational backbone networks convert optical signals back to the electrical state for routing and signal regeneration at each major node in the network. Optical-Electrical-Optical (O-E-O) systems are not optimal, since the periodic conversion to the electrical state and speed limitations of electronic components create a bottleneck in the network. The role of optics in backbone networks is transitioning from simply providing a reliable point-to-point communication link, to optically routing data through the network. Optical amplification has added the capability of re-amplifying transmitted data while in the optical state and, as other new optical networking technologies become available, optical components are expected to replace their electronic counter parts; thus approaching the ideal Optical-Optical-Optical (O3) solution. The optical processing components needed to process and store packets for a packet-switched network are not expected to materialize in the near future; so it is expected that, initially, a circuit switched optical layer will be generated below existing IP layer for data routing. A method of generating a circuit in an optical network is Optical Multiple Protocol Lamda Switching (OMPλS). For OMPλS, the wavelength of the optical carrier is used as an out-of-band label to route data through the network without requiring periodic conversion to the electrical state. Presented is a method of adding a second dimension of optical encoding, as an out-of-band label, to be used for routing data through a label-switched network. Combining wavelength and code multiplexing techniques generates an O3 circuit-switched network with a data capacity of up to 5.7 Tb/s on each point-to-point link in the network. The proposed architecture uses two stages to process and map labels for each bit transmitted through the network. The architecture for the Dual Stage Optical Label Switch (DSOLS) is presented along with simulation results of its expected performance. The Virtual Photonics Integrator (VPI) simulations package is used to analyze system performance. VPI lacked a model for the Gain Clamped Semiconductor Amplifier (GCSOA), needed to simulate the complete DSOLS architecture. A steady state model of a GCSOA is developed and used in VPI to analyze a DSOLS. Using data generated from simulations a performance metric, based on Bit Error Rate (BER), to be used by an upper level routing algorithm is presented. Finally, a method of measuring the metric for a 2x2 (two codes and two wavelengths) DSOLS is described.

Subject Area

Electrical engineering

Recommended Citation

Medrano, John Daniel, "Dual stage optical multi-protocol label switching using out-of-band wavelength and code properties" (2005). ETD Collection for University of Texas, El Paso. AAI3196418.