Abstract: In this paper, we present a new hybrid optical burst switcharchitecture (HOBS) that takes advantage of the pre-transmission idle
time during lightpath establishment. In dynamic circuit switching (wavelength routing) networks, capacity is immediately hardreserved
upon the arrival of a setup message at a node, but it is used at least a round-trip time delay later. This waste of resources
is significant in optical multi-gigabit networks and can be used to transmit traffic of a lower class of service in a non-competing
way. The proposed hybrid OBS architecture, takes advantage of this idle time to transmit one-way optical bursts of a lower class of
service, while high priority data explicitly requests and establishes end-to-end lightpaths. In the proposed scheme, the two control
planes (two-way and one-way OBS reservation) are merged, in the sense that each SETUP message, used for the two-way lightpath
establishment, is associated with one-way burst transmission and therefore it is modified to carry routing and overhead information
for the one-way traffic as well. In this paper, we present the main architectural features of the proposed hybrid scheme and further
we assess its performance by conducting simulation experiments on the NSF net backbone topology. The extensive network study
revealed that the proposed hybrid architecture can achieve and sustain an adequate burst transmission rate with a finite worst case
delay.
Abstract: In this paper, a novel configuration is proposed for
the implementation of an almost all-opticalswitcharchitecture
called the scheduling switch, which when combined with appropriate
wait-for-reservation or tell-and-go connection and flow
control protocols provides lossless communication for traffic
that satisfies certain smoothness properties. An all-optical 2 2
exchange/bypass (E/B) switch based on the nonlinear operation
of a semiconductor optical amplifier (SOA) is considered as the
basic building block of the scheduling switch as opposed to active
SOA-based space switches that use injection current to switch
between ON and OFF states. The experimental demonstration of
the optically addressable 2 2 E/B, which is summarized for
10–Gb/s data packets as well as synchronous digital hierarchy
(SDH)/STM-64 data frames, ensures the feasibility of the proposed
configuration at high speeds, with low switching energy and low
losses during the scheduling process. In addition, it provides
reduction of the number of required components for the construction
of the scheduling switch, which is calculated to be 50% in the
number of active elements and 33% in the fiber length.
Abstract: We present an almost all-optical node
architecture suitable for on-the-fly packet and burst
switching without losses. The operation of the node is based
on wavelength converters for mapping the incoming to the
outgoing links, and for intra-node contention resolution. The
node can be built out of commercially available equipment,
and is easily scalable, with respect to the number of its
incoming and outgoing links, by simple addition of
components.
Abstract: We present a 40 Gb/s asynchronous self-routing network and node architecture that exploits bit
and packet level optical signal processing to perform synchronization, forwarding and
switching. Optical packets are self-routed on a hop-by-hop basis through the network by using
stacked optical tags, each representing a specific optical node. Each tag contains control signals
for configuring the switching matrix and forwarding each packet to the appropriate outgoing
link and onto the next hop. Physical layer simulations are performed, modeling each optical subsystem
of the node showing acceptable signal quality and Bit Error Rates. Resource reservationbased
signaling algorithms are theoretically modeled for the control plane capable of providing
high performance in terms of blocking probability and holding time.
Abstract: In this article, we present a detailed performance
evaluation of a hybrid opticalswitching (HOS)
architecture called Overspill Routing in Optical Networks
(ORION). The ORION architecture combines
(optical) wavelength and (electronic) packet switching,
so as to obtain the individual advantages of both switching
paradigms. In particular, ORION exploits the possible insertions/extractions, to reduce the necessary
interfaces, do not deteriorate performance and thus the
use of traffic concentrators assure ORION’s economic
viability.
idle periods of established lightpaths to transmit
packets destined to the next common node, or even
directly to their common end-destination. Depending
on whether all lightpaths are allowed to simultaneously
carry and terminate overspill traffic or overspill is restricted
to a sub-set of wavelengths, the architecture
limits itself to constrained or un-constrained ORION. To
evaluate both cases, we developed an extensive network
simulator where the basic features of the ORION architectureweremodeled,
including suitable edge/core node
switches and load-varying sources to simulate overloading
traffic conditions. Further, we have assessed various
aspects of the ORION architecture including two
basic routing/forwarding policies and various buffering
schemes. The complete network study shows that
ORION can absorb temporal traffic overloads, as intended,
provided sufficient buffering is present.We also
demonstrate that the restriction of simultaneous packet
Abstract: We present an architecture for implementing optical
buffers, based on the feed-forward-buffer concept, that can truly
emulate input queuing and accommodate asynchronous packet
and burst operation. The architecture uses wavelength converters
and fixed-length delay lines that are combined to form either a
multiple-input buffer or a shared buffer. Both architectures are
modular, allowing the expansion of the buffer at a cost that grows
logarithmically with the buffer depth, where the cost is measured
in terms of the number of switching elements, and wavelength
converters are employed. The architectural design also provides
a tradeoff between the number of wavelength converters and their
tunability. The buffer architectures proposed are complemented
with scheduling algorithms that can guarantee lossless communication
and are evaluated using physical-layer simulations to
obtain their performance in terms of bit-error rate and achievable
buffer size.
Abstract: We present an architecture for implementing optical
buffers, based on the feed-forward-buffer concept, that can truly
emulate input queuing and accommodate asynchronous packet
and burst operation. The architecture uses wavelength converters
and fixed-length delay lines that are combined to form either a
multiple-input buffer or a shared buffer. Both architectures are
modular, allowing the expansion of the buffer at a cost that grows
logarithmically with the buffer depth, where the cost is measured
in terms of the number of switching elements, and wavelength
converters are employed. The architectural design also provides
a tradeoff between the number of wavelength converters and their
tunability. The buffer architectures proposed are complemented
with scheduling algorithms that can guarantee lossless communication
and are evaluated using physical-layer simulations to
obtain their performance in terms of bit-error rate and achievable
buffer size.
Abstract: In this paper we discussed different switcharchitectures. We focus mainly on optical buffering. We investigate an all-optical buffer architecture comprising of cascaded stages of quantum-dot semiconductor optical amplifier- based tunable wavelength converters, at 160 Gb/s. We also propose the optical buffer with multi-wavelength converters based on quantum-dot semiconductor optical amplifiers. We present multistage switching fabrics with optical buffers, where optical buffers are based on fibre delay lines and are located in the first stage. Finally, we describe a photonic asynchronous packet switch and show that the employment of a few optical buffer stages to complement the electronic ones significantly improves the switch performance. We also propose two asynchronous optical packet switching node architectures, where an efficient contention resolution is based on controllable optical buffers and tunable wavelength converters TWCs.
Abstract: The authors demonstrate an optical buffer architecture which is implemented using quantum dot semiconductor optical amplifiers (QD-SOAs) in order to achieve wavelength conversion with regenerative capabilities, for all optical packet switched networks. The architecture consists of cascaded programmable delay stages that minimise the number of wavelength converters required to implement the buffer. Physical layer simulations have been performed in order to reveal the potential of this scheme as well as the operating and device parameters of QD-SOA-based wavelength converters. The results obtained have indicated that, up to three time-slot interchanger (TSI) cascaded stages show good performance at 160 Gb/s in the 1550 nm communication window.
Abstract: The objective of this research is to propose two new optical procedures for packet routing and forwarding in the framework of transparent optical networks. The single-wavelength label-recognition and packet-forwarding unit, which represents the central physical constituent of the switching node, is fully described in both cases. The first architecture is a hybrid opto-electronic structure relying on an optical serial-to-parallel converter designed to slow down the label processing. The remaining switching operations are done electronically. The routing system remains transparent for the packet payloads. The second architecture is an all-opticalarchitecture and is based on the implementation of all-optical decoding of the parallelized label. The packet-forwarding operations are done optically. The major subsystems required in both of the proposed architectures are described on the basis of nonlinear effects in semiconductor optical amplifiers. The experimental results are compatible with the integration of the whole architecture. Those subsystems are a 4-bit time-to-wavelength converter, a pulse extraction circuit, a an optical wavelength generator, a 3 x 8 all-optical decoder and a packet envelope detector.
Abstract: We present a detailed performance evaluation of a
hybrid opticalswitching architecture called Overspill Routing in
Optical Networks (ORION). The ORION architecture combines
wavelength and (electronic) packet switching, so as to obtain the
advantages of both switching paradigms. We have developed an
extensive network simulator where the basic features of the
ORION architecture were modeled, including suitable loadvarying
sources and edge/core node architectures. Various aspects
of the ORION architecture were studied including the routing
policies used (i.e. once ORION always ORION and lightpath reentry)
and the various options available for the buffer
architecture. The complete network study shows that ORION can
absorb temporary traffic overloads, as intended, provided
sufficient buffering is present.
Abstract: This paper describes recent research activities and results in the area of photonic switching
carried out within the Virtual Department on Switching (VDS) of the European e-Photon/
ONe Network of Excellence. Contributions from outstanding European research groups in
this field are collected to offer a platform for future research in opticalswitching. The paper
contains the main topics related to network scenarios, switcharchitectures and experiments,
with an effort to investigate synergies and challenging opportunities for collaboration
and integration of research expertise in the field.
Abstract: This paper presents a summary of Optical Burst Switching (OBS) research within the VI framework program e-Photon/ONe network of excellence. The paper includes network aspects such as routing techniques, resilience and contention resolution, together with burst switcharchitectures. On the other hand, we also discuss traffic analysis issues, Quality of Service (QoS) schemes, TCP/IP over OBS and physical layer aspects for OBS.
Abstract: This paper presents a summary of Optical Burst Switching (OBS) research within the VI framework program e-Photon/ONe
network of excellence. The paper includes network aspects such as routing techniques, resilience and contention resolution, together
with burst switcharchitectures. On the other hand, we also discuss traffic analysis issues, Quality of Service (QoS) schemes, TCP/IP
over OBS and physical layer aspects for OBS.
Abstract: Digital optical logic circuits capable of performing bit-wise signal processing are critical building blocks for the realization of future high-speed packet-switched networks. In this paper, we present recent advances in all-optical processing circuits and examine the potential of their integration into a system environment. On this concept, we demonstrate serial all-optical Boolean AND/XOR logic at 20 Gb/s and a novel all-optical packet clock recovery circuit, with low capturing time, suitable for burst-mode traffic. The circuits use the semiconductor-based ultrafast nonlinear interferometer (UNI) as the nonlinear switching element. We also present the integration of these circuits in a more complex unit that performs header and payload separation from short synchronous data packets at 10 Gb/s. Finally, we discuss a method to realize a novel packet scheduling switcharchitecture, which guarantees lossless communication for specific traffic burstiness constraints, using these logic units.
Abstract: In this paper, we review recent advances in ultrafast optical time-domain technology with emphasis on the use in optical packet switching. In this respect, several key building blocks, including high-rate laser sources applicable to any time-division-multiplexing (TDM) application, optical logic circuits for bitwise processing, and clock-recovery circuits for timing synchronization with both synchronous and asynchronous data traffic, are described in detail. The circuits take advantage of the ultrafast nonlinear transfer function of semiconductor-based devices to operate successfully at rates beyond 10 Gb/s. We also demonstrate two more complex circuits-a header extraction unit and an exchange-bypass switch-operating at 10 Gb/s. These two units are key blocks for any general-purpose packet routing/switching application. Finally, we discuss the system perspective of all these modules and propose their possible incorporation in a packet switcharchitecture to provide low-level but high-speed functionalities. The goal is to perform as many operations as possible in the optical domain to increase node throughput and to alleviate the network from unwanted and expensive optical-electrical-optical conversions.
