DynaSPOT: Dynamic Services Provisioned Optical Transport Test-bed – Achieving Multi-Rate Multi-Service Dynamic Provisioning using Light-trail Technology

We report on the DynaSPOT (Dynamic Services Provisioned Optical Transport) test-bed – a next-generation metro ring architecture that facilitates provisioning of emerging services such as Triple Play, Video-on-Demand (VoD), Pseudo Wire Edge to Edge Emulation (PWE3), IPTV and Data Center Storage traffic. The test-bed is based on the recently proposed Strongly connected Light-trail (SLiT) technology that enables the triple features of dynamic provisioning, spatial sub-wavelength grooming and optical multicasting – that are quintessential for provisioning of the aforementioned emerging services. SLiT technology entails the use of a bidirectional optical wavelength bus that is time-shared by nodes through an out-of-band control channel. To do so, the nodes in a SLiT exhibit architectural properties that facilitate bus function. These properties at the network side include ability to support the dual signal flow of drop and continue as well as passive add, while at the client side include the ability to store data in order to support time-shared access. The latter (client side) improvisation is done through a new type of transponder card – called the trailponder that provides for storage (electronic) of data and fast transmission (burst-mode) onto the SLiT. Further in order to efficiently provision services over the SLiT, there is a need for an efficient algorithm that facilitates meeting of service requirements. To meet service requirements we propose a dynamic bandwidth allocation algorithm that allocates data time-slots to nodes based on a valuation method. The valuation method is principally based on an auctioning scheme whereby nodes send their valuations (bids) and a controller node responds to bids by sending a grant message. The auctioning occurs in the control layer, out-of-band and ahead in time. The novelty of the algorithm is the ability to take into consideration the dual service requirements of bandwidth request as well as delay sensitivity. At the hardware level, implementation is complex – as our trailponders are layer-2 devices that have limited service differentiation capability. Here, we propose a dual VLAN tag and GFP based unique approach that is used for providing service differentiation at layer-2. Another innovation in our test-bed is the ability to support multispeed traffic. While some nodes function at 1 Gbps, and others function at 2.5 Gbps (using corresponding receivers), a select few nodes can support both 1 Gbps and 2.5 Gbps operation. This novel multi-speed support coalesced with the formerly mentioned multi-service support is a much needed boost for services in the metro networks. We showcase the test-bed and associated results as well as descriptions of hardware subsystems.