Distributed abstraction and verification of an installed optical fibre network

The management of wavelength routed optical mesh networks is complex with many potential light path routes and numerous physical layer impairments to transmission performance. This complexity can be reduced by applying the ideas of abstraction from computer science where different equipment is described in the same basic terms. The noise-to-signal ratio can be used as a metric to describe the quality of transmission performance of a signal propagated through a network element and accumulates additively through a sequence of such elements allowing the estimation of end-to-end performance. This study aims to explore the robustness of the noise-to-signal ratio metric in an installed fibre infrastructure. We show that the abstracted noise-to-signal ratio is independent of the observers and their location. We confirm that the abstracted noise-to-signal ratio can reasonably predict the performance of light-paths subsequently set in our network. Having a robust network element abstraction that can be incorporated into routeing engines allows the network management controller to make decisions on the most effective way to use the network resources in terms of the routeing and data coding format.

Optical network democratization

The current Internet infrastructure is not able to support independent evolution and innovation at physical and network layer functionalities, protocols and services, while at same time supporting the increasing bandwidth demands of evolving and heterogeneous applications. This paper addresses this problem by proposing a completely democratized optical network infrastructure. It introduces the novel concepts of the optical white box and bare metal optical switch as key technology enablers for democratizing optical networks. These are programmable optical switches whose hardware is loosely connected internally and is completely separated from their control software. To alleviate their complexity, a multi-dimensional abstraction mechanism using software-defined network technology is proposed. It creates a universal model of the proposed switches without exposing their technological details. It also enables a conventional network programmer to develop network applications for control of the optical network without specific technical knowledge of the physical layer. Furthermore, a novel optical network virtualization mechanism is proposed, enabling the composition and operation of multiple coexisting and application-specific virtual optical networks sharing the same physical infrastructure. Finally, the optical white box and the abstraction mechanism are experimentally evaluated, while the virtualization mechanism is evaluated with simulation.

Software defined networking (SDN) over space division multiplexing (SDM) optical networks: features, benefits and experimental demonstration

We present results from the first demonstration of a fully integrated SDN-controlled bandwidth-flexible and programmable SDM optical network utilizing sliceable self-homodyne spatial superchannels to support dynamic bandwidth and QoT provisioning, infrastructure slicing and isolation. Results show that SDN is a suitable control plane solution for the high-capacity flexible SDM network. It is able to provision end-to-end bandwidth and QoT requests according to user requirements, considering the unique characteristics of the underlying SDM infrastructure.

Fully-elastic multi-granular network with space/frequency/time switching using multi-core fibres and programmable optical nodes

We present the first elastic, space division multiplexing, and multi-granular network based on two 7-core MCF links and four programmable optical nodes able to switch traffic utilising the space, frequency and time dimensions with over 6000-fold bandwidth granularity. Results show good end-to-end performance on all channels with power penalties between 0.75 dB and 3.7 dB.

Experimental demonstration of an OpenFlow based software-defined optical network employing packet, fixed and flexible DWDM grid technologies on an international multi-domain testbed

Software defined networking (SDN) and flexible grid optical transport technology are two key technologies that allow network operators to customize their infrastructure based on application requirements and therefore minimizing the extra capital and operational costs required for hosting new applications. In this paper, for the first time we report on design, implementation & demonstration of a novel OpenFlow based SDN unified control plane allowing seamless operation across heterogeneous state-of-the-art optical and packet transport domains. We verify and experimentally evaluate OpenFlow protocol extensions for flexible DWDM grid transport technology along with its integration with fixed DWDM grid and layer-2 packet switching.

Programmable on-chip and off-chip network architecture on demand for flexible optical intra-datacenters

The paper presents a novel network architecture on demand approach using on-chip and-off chip implementations, enabling programmable, highly efficient and transparent networking, well suited for intra-datacenter communications. The implemented FPGA-based adaptable line-card with on-chip design along with an architecture on demand (AoD) based off-chip flexible switching node, deliver single chip dual L2-Packet/L1-time shared optical network (TSON) server Network Interface Cards (NIC) interconnected through transparent AoD based switch. It enables hitless adaptation between Ethernet over wavelength switched network (EoWSON), and TSON based sub-wavelength switching, providing flexible bitrates, while meeting strict bandwidth, QoS requirements. The on and off-chip performance results show high throughput (9.86Ethernet, 8.68Gbps TSON), high QoS, as well as hitless switch-over.

Demonstration of low latency Intra/Inter Data-Centre heterogeneous optical sub-wavelength network using extended GMPLS-PCE control-plane

This paper reports on the first user/application-driven multi-technology optical sub-wavelength network for intra/inter Data-Centre (DC) communications. Two DCs each with distinct sub-wavelength switching technologies, frame based synchronous TSON and packet based asynchronous OPST are interconnected by a WSON inter-DC communication. The intra/inter DC testbed demonstrates ultra-low latency (packet-delay <270 µs and packet-delay-variation (PDV)<10 µs) flexible data-rate traffic transfer by point-to-point, point-to-multipoint, and multipoint-to-(multi)point connectivity, highly suitable for cloud based applications and high performance computing (HPC). The extended GMPLS-PCE-SLAE based control-plane enables innovative application-driven end-to-end sub-wavelength path setup and resource reservation across the multi technology data-plane, which has been assessed for as many as 25 concurrent requests.

High performance and flexible FPGA-based time shared optical network (TSON) metro node

The paper presents the architecture, implementation and evaluation of the flexible and finely granular Time Shared Optical Network (TSON) metro node. It focuses on the FPGA-based Layer 2 TSON metro node system. The experimentally measured results show exceptional performance of up to 8.68 Gbps throughput per 10 Gbps port, 95.38% of theoretical maximum throughput, latency of less than 160 μsec and jitter of less than 25 μsec. The TSON topology agnostic node/network also delivers differentiated QoS latency levels yet always guaranteed (contention-free) by deploying diverse time-slice allocation schemes.

Experimental demonstration of OpenFlow-enabled media ecosystem architecture for high-end applications over metro and core networks

In this paper, a novel Software-Defined Networking (SDN) architecture is proposed for high-end Ultra High Definition (UHD) media applications. UHD media applications require huge amounts of bandwidth that can only be met with high-capacity optical networks. In addition, there are requirements for control frameworks capable of delivering effective application performance with efficient network utilization. A novel SDN-based Controller that tightly integrates application-awareness with network control and management is proposed for such applications. An OpenFlow-enabled test-bed demonstrator is reported with performance evaluations of advanced online and offline media- and network-aware schedulers.

Field trial of a 1.5 Tb/s adaptive and gridless OXC supporting elastic 1000-fold all-optical bandwidth granularity

An adaptive gridless OXC is implemented using a 3D-MEMS optical backplane plus optical modules (sub-systems) that provide elastic spectrum and time switching functionality. The OXC adapts its architecture on demand to fulfill the switching requirements of incoming traffic. The system is implemented in a seven-node network linked by installed fiber and is shown to provide suitable architectures on demand for three scenarios with increasing traffic and switching complexity. In the most complex scenario, signals of mixed bit-rates and modulation formats are successfully switched with flexible per-channel allocation of spectrum, time and space, achieving over 1000-fold bandwidth granularity and 1.5 Tb/s throughput with good end-to-end performance.

Integrated OpenFlow-GMPLS control plane: an overlay model for software defined packet over optical networks

Bandwidth demands resulting from generated traffics by emerging applications, when aggregated at the edge of the networks for transport over core networks can only be met with high-capacity WDM circuit switched optical networks. An efficient end-to-end delivery of packet streams in terms of network control, operation and management is one of the key challenges for the network operators. Therefore, a unified control and management plane for both packet and optical circuit switch domains is a good candidate to address this need. In this paper a novel software-defined packet over optical networks solution based on the integration of OpenFlow and GMPLS control plane is experimentally demonstrated. The proposed architecture, experimental setup, and average flow setup time for different optical flows are reported. The performance of the extended OpenFlow controller is also presented and discussed.

Time Shared Optical Network (TSON): a novel metro architecture for flexible multi-granular services

This paper presents the Time Shared Optical Network (TSON) as metro mesh network architecture for guaranteed, statistically-multiplexed services. TSON proposes a flexible and tunable time-wavelength assignment along with one-way tree-based reservation and node architecture. It delivers guaranteed sub-wavelength and multi-granular network services without wavelength conversion, time-slice interchange and optical buffering. Simulation results demonstrate high network utilization, fast service delivery, and low end-to-end delay on a contention-free sub-wavelength optical transport network. In addition, implementation complexity in terms of Layer 2 aggregation, grooming and optical switching has been evaluated.

A novel ingress node design for video streaming over optical burst switching networks

This paper introduces a novel ingress node design which takes advantage of video data partitioning in order to deliver enhanced video streaming quality when using H.264/AVC codec over optical burst switching networks. Ns2 simulations show that the proposed scheme delivers improved video traffic quality without affecting other traffic, such as best effort traffic. Although the extra network load is comparatively small, the average gain in video PSNR was 5 dB over existing burst cloning schemes, with a maximum end-to-end delay of 17 ms, and jitter of less than 0.35 ms.

Energy aware planning of multiple virtual infrastructures over converged optical network and IT physical resources

This paper studies energy efficient planning of multiple concurrent virtual infrastructures over a converged physical infrastructure incorporating integrated optical network and IT resources. An MILP model for virtualization of the underlying physical resources is proposed and validated achieving significant energy savings.

Gridless optical networking field trial: flexible spectrum switching, defragmentation and transport of 10G/40G/100G/555G over 620-km field fiber

We present results from the first gridless networking field trial with flexible spectrum switching nodes and 620 km of installed fibre links. Signals at 10G, 12.25G, 42.7G, DP-QPSK 40G, DP-QPSK 100G and 555G are generated, successfully transported and switched using flexible, custom spectrum allocation per channel. Spectrum defragmentation is demonstrated using integrated SOA-MZI wavelength converters. Results show error-free end-to-end performance (BER<1e-9) for the OOK channels and good pre-FEC BER performance with sufficient margin to FEC limit for the 40G and 100G coherent channels as well as for the 555G super-channel.

An impairment-aware virtual optical network composition mechanism for future Internet

In this paper, a novel Infrastructure as a Service architecture for future Internet enabled by optical network virtualization is proposed. Central to this architecture is a novel virtual optical network (VON) composition mechanism capable of taking physical layer impairments (PLIs) into account. The impact of PLIs on VON composition is investigated based on both analytical model of PLIs and industrial parameters. Furthermore, the impact of network topology on VON composition is evaluated.

Experimental demonstration of gridless spectrum and time optical switching

An experimental demonstration of gridless spectrum and time switching is presented. We propose and demonstrate a bit-rate and modulation-format independent optical cross-connect architecture, based on gridless spectrum selective switch, 20-ms 3D-MEMS and 10-ns PLZT optical switches, that supports arbitrary spectrum allocation and transparent time multiplexing. The architecture is implemented in a four-node field-fiber-linked testbed to transport continuous RZ and NRZ data channels at 12.5, 42.7 and 170.8 Gb/s, and selectively groom sub-wavelength RZ channels at 42.7 Gb/s. We also showed that the architecture is dynamic and can be reconfigured to meet the routing requirements of the network traffic. Results show error-free operation with an end-to-end power penalty between 0.8 dB and 5 dB for all continuous and sub-wavelength channels.

Optical grooming switch with regenerative functionality for transparent interconnection of networks

We demonstrate a regenerative optical grooming switch for buffer-less interconnection of metro/access and metro/core ring networks with switching functionality in time, space and wavelength domain. Key functionalities of the router are the traffic aggregation with time-slot interchanging (TSI) functionality, the WDM-to-ODTM multiplexing and the OTDM-to-WDM demultiplexing of high-speed channel into lower bit-rate tributaries as well as multi-wavelength all-optical 2R regeneration of several higher-speed signals. BER and Q-factor measurements of different switching scenarios show excellent performance with no error floor and Q-factors above 21 dB.

40 Gbit/s asynchronous digital optical regenerator

We present the first experimental demonstration of an asynchronous digital optical regenerator at 42.67 Gbit/s. The system effectively retimes incoming asynchronous data bursts to a local clock without burst mode clock recovery and converts the signal to a desired wavelength and duty cycle.

Optical node with time-space-and-wavelength domain contention resolution, deflection and dropping capability

We experimentally demonstrate an optical node with time-space-and- wavelength domain contention resolution, deflection and dropping capability. The node is composed of an optical buffer based on an optical crossconnect and a wavelength converter. Although the experimental results are shown at 10 Gbit/s the bitrate can be increased substantially. Bit-error rate measurements are shown, sustaining only 3.5 dB power penalty after 10mus of optical buffering and agile wavelength conversion over 18nm span.