Enabling multipath optical routing with hybrid differential delay compensation

Historically, Internet traffic has been routed over the shortest path: that was convenient for best-effort data traffic, but it is not always suitable for today’s scenario where applications can require bandwidth higher than what is available in a single link, even when provided by an optical wavelength-channel. Multi-path (MP) routing is a network functionality that provides more capacity, reduces the probability of link congestion and increases the availability of the transport service. This paper elaborates on techniques to mitigate the differential delay in all optical networks, recognized as the main problem of multi-path (MP) routing. This work shows how hybrid differential delay compensation (H-DDC) can greatly reduce the use of expensive reconstruction buffers in all optical networks implementing MP optical routing. A novel mixed integer linear programming formulation is proposed for the novel wavelength + H-DDC assignment problem: distributed fiber delay lines (FDL)s combined with electronic reconstruction buffers collocated at optical regeneration points. Numerical results based on commercially available (and rack mountable) FDLs demonstrate the effectiveness of H-DDC in medium size transport networks.