Abstract
In this paper, we report on the dynamic services provisioned optical
transport (DynaSPOT) test-bed—a next-generation metro ring architecture
that facilitates provisioning of emerging services such as Triple Play, Video-on-Demand
(VoD), pseudowire 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 subwavelength 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 (electronic) storage 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 Gb/s, and others function at 2.5 Gb/s (using corresponding receivers),
a select few nodes can support both 1- and 2.5-Gb/s operation. This novel
multispeed support coalesced with the formerly mentioned multiservice 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.
© 2008 IEEE
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