ENGINE – Engineering Next Generation Optical Transport NEtworks
(TEC2008-02634)
January 2009 – December 2011
Role: Technical Coordinator
One of the objectives of the ENGINE (Engineering Next Generation optIcal traNsport nEtworks) project will be the upgrade of the ROADM nodes we developed in the framework of the “Red INteligente GMPLS/ASON con Integración de Nodos reconfiGurables (RINGING)” project (TEC-2005-08051-C03-02) to enable transmissions at 10 Gb/s and beyond (40-100 Gb/s). Nevertheless, the leap from 10 Gb/s to higher bit rates poses some technical problems which have to be properly investigated. Typically, when transmission speed is increased, marginal impairments such as polarization mode dispersion (PMD) become pronounced, limiting the transmission distance without signal regeneration. Therefore, another objective of the ENGINE project is also to develop and integrate in the ROADM node, modules for optical signal regeneration, chromatic (CD) and polarization-mode dispersion (PMD) compensation, in combination with wavelenght conversion (WC) techniques. On the other hand, most operators are seeing the control plane as the key factor to migrate from ring-based to meshed-based optical transport network. To migrate, thus, our experimental platform to a mesh topology, another objective of the ENGINE project will be the implementation, starting from the ROADMs, of Optical Cross Connect (OXC) nodes.In such high-capacity reconfigurable optical transport networks, the control plane must manage efficiently available wavelenghts as well as to react in case of degradation of the optical signals due to the physical impariments arisen from the propagation through the optical fibers. In the latter case, the control plane dynamically drops the degraded channels in order to regenerate the signal or to compensate the dispersion. To accomplish to this functionality, therefore, it is of critical value to efficiently monitor the accumulated physical impairments. In this context, another objective of the ENGINE project is to design and demonstrate monitoring techniques for CD and PMD. Moreover, if a 40 Gb/s (and beyond) signal has to travel through DWDM 50 GHz spaced channels, a lot of inter-symbol interference will raise. Multilevel modulation formats reduce the symbol rate and therefore alleviate the influence of impairments while advanced modulation formats together with digital signal processing-enhanced optics will make 40 Gb/s systems possible. In ENGINE, we will investigate on electronic digital signal processing as well as all-optical PMD compensation.The ENGINE project will also design and evaluate routing and wavelenght assignment algorithms which take into account the physical impairments to decide how to accomodate the connection requests triggered from the client networks (IP, SDH, Ethernet, etc.). Such algorithms will be tested over the experimental platform (arising from the RINGING project and completed accomplishing the previous objectives of ENGINE). Assuming that a network must be seen in its overall structure, which means to consider not just the transport layer but also the client networks. The ENGINE project will carry out interwoking studies aimed, firslty, to design efficient dynamic traffic grooming strategies to optimize the bandwidth utilization of the wavelenghts; and secondly, to design coordinated protection strategies between transport and client layers in order to cover a wide set of failures which can occur. In both cases, an MPLS over optical transport layer will be assumed and the designed startegies will be experimentally evaluated. Finally, the potentiality of GMPLS-based control plane to efficiently manage the network resources for hybrid Optical Circuit Switching (OCS) and Optical Burst Switching (OBS) network nodes will be investigated, since OBS networks, capable of switching smaller granularities than wavelenghts in the optical layer, are seen as the long-term solution for optical networks.