Multipath routing with differential delay compensation for optical networks

Internet traffic volume is ever increasing, and emerging applications impose stringent requirements on bandwidth, delay and availability of network services. Those requirements can be better met by using multipath (MP) routing, which is a network functionality that allows to split data traffic from a source to a destination among a set of multiple paths (disjoint or partially disjoint MP set), and to reconstruct it at destination as a single flow. Today's networks offer MP capability; however common networking practice seldom exploits it mainly because of the differential delay (DD) of the MP set (differences on delay experienced by the MP set). At the packet level the DD produces packet reordering which forces the introduction of reconstruction operations at destination. At the optical level, when using dedicated 1+1 protection the DD is compensated at the source to avoid loss of information when a failure occurs. In both cases the DD compels to introduce electronic buffers at the end points for DD compensation (DDC). In this work we study an optimization problem for multipath routing with DDC in transparent optical networks involving minimization of compensation buffers in the network. Previous works considered only distributed buffers architectures that incurs in costly opto-electronic and electro-optic (OEO) conversions. We introduce for the first time the use of fiber delay lines (FDL)s as a DDC technique to reduce the use of electronic buffers and OEO conversions. Moreover, in order to further reduce the OEO conversions in the network, we proposed a model that considers the introduction of distributed electronic buffers for DDC in accordance to regeneration of optical signals. We present numerical results illustrating the gain achieved by using FDLs for DDC in real life topologies.