COLLOQUIUM
Department of Computer Science and Engineering
University of South Carolina
 
Advanced Digital Designs in 
Optical Burst Switching Systems

Yuhua Chen

Department of Computer Science and Engineering
Washington University

Date: February 16, 2004 (Monday)
Time: 10:00-11:00AM
Place: Swearingen 1A03 (Faculty Lounge)

Abstract

Emerging large-scale experiments in many areas of science, such as
high-energy physics, nuclear physics, and biological sciences, are
anticipated to generate up to several petabytes of data that will be
transferred to geographically distant computing
facilities. Transferring such petabyte-scale data in a timely manner
over the network presents serious technical challenges to the
networking and science communities. It appears likely that petabit
routers will have to use optical switching technology to move the data
between input and output links. Optical Burst Switching (OBS) is a
promising candidate technology that makes the best use of electronics
and optics. An OBS network carries data over WDM links with tens, or
preferably hundreds of channels per link. At least one channel per
link is reserved to carry control information. Shortly before the
transmission of a data burst, a Burst Header Cell (BHC) is sent on the
control channel. The BHC is converted to electronic form and processed
by the control subsystem of the OBS router. The OBS router selects an
outgoing channel for the data burst, sets up an optical path before
the burst arrives, and releases the path afterwards. The data burst
remains in the optical domain and passes through the OBS network
transparently.  
In this talk, I will focus on the advanced digital design solutions I
devised to two of the problems in the design of the control subsystem
of an OBS router. The first is how to design and implement link
scheduling algorithms that are efficient for both small and large
bursts. I will present the lookahead resource management mechanism
that assigns bursts to channels based on projected future states. I
will also describe a pipelined super fast burst controller design. The
controller achieves a throughput of two clock cycles per burst header
processing regardless of the number of channels per link, which meets
the stringent processing requirement for OBS systems with 256 WDM
channels per link at 10 Gb/s each. The second design problem is how to
generalize link scheduling to provide Quality-of-Service (QoS) while
keeping the complexity low enough to enable high performance hardware
implementations. The novel Contour-Based Priority (CBP) algorithm
provides differentiated services without the need for optical
buffering. The algorithm requires only a single memory access per
update and is well-suited to high performance cost-effective hardware
implementation. I will also talk about my past hardware prototyping
experiences and future research directions.

Dr. Yuhua Chen has been working full-time as a Research Associate and
a Hardware Design Engineer at Applied Research Laboratory, Washington
University in St. Louis since 1998. She received the MS degree in
Computer Science in 1997 and the MS degree in Electrical Engineering
in 1998. She worked on her doctoral degree on a part-time basis under
the supervision of Dr. Jonathan S. Turner and received the Doctor of
Science degree in Electrical Engineering in August, 2003. Dr. Chen has
been involved in ASIC, FPGA and system designs in several hardware
prototype systems. Her recent research interests include several areas
of Computer Engineering, such as optical networks, networking system
hardware/architecture design, reconfigurable System-on-a-Chip (SoC),
Networks-on-Chip (NoC), and system prototyping.