Optical Label Switching Networks Research Articles

High spectral efficiency scheme for future all optical label switching network

A high spectral efficiency scheme for all optical label switching (AOLS) network is introduced. The vestigial sideband (VSB) payload with wavelength labeling is proposed in beyond 40Gb/s AOLS networks. Two different label wavelength schemes are considered. The minimum 20dB channel bandwidth of payload and label is 0.40nm in 43Gb/s systems which confirm the payload power penalty less than 1dB at the receiver.

A compact all-optical subcarrier label-swapping system using an integrated EML for 10-Gb/s optical label-switching networks

We propose a compact and simple all-optical subcarrier-multiplexed (SCM) label-swapping system employing an integrated electroabsorption modulation laser and a semiconductor optical amplifier based Mach-Zehnder interferometer wavelength converter. The experiments demonstrated error-free all-optical label swapping for the 155-Mb/s label and 10-Gb/s payload over two optical label-switching network nodes with less than 0.7-dB power penalty on the payload. The majority of the components in this SCM label-swapping system can be realized on a semiconductor platform (e.g., InP), which implies a step toward possible monolithic or hybrid integration of the all-optical label-swapping system in the future.

All-optical label processor∕erasure for label swapping of 12.5 Gbit∕s spectrally separated bit-serial DPSK label and payload

A novel all-optical label processor/erasure for DPSK spectrally separated label and payload is demonstrated. Experimental results show the recognition of two different labels at 12.5 Gbit/s at distinct outputs, while the label is simultaneously erased allowing for a new label insertion. The low power and asynchronous label processor/erasure can be scaled to distinguish a larger number of labels, to operate at higher bit rate, and then can be potentially used in an optical label switching network.

All optical labeling scheme with vestigial sideband payload

A novel scheme based on 40Gb/s vestigial sideband modulation for optical payload and label multiplex and separation in all optical label switching (AOLS) networks is firstly proposed and experimentally demonstrated. The payload is combined and separated with wavelength labels by optical filters. The experiment results show that after label separation, the power penalties of payload and label are both very little. The influence of the wavelength difference between label and payload is also discussed. The power penalty of payload can be less than 1dB as long as the wavelength difference is larger than 0.1nm. This scheme highly reduces the channel bandwidth of payload and label and is proposing to be used in future optical Internet.

BER Performance of All-Optical Subcarrier Label Swapping With 2R Regeneration

This paper proposes and demonstrates an all-optical subcarrier label swapping subsystem with 2R (reamplification, reshaping) optical regeneration and wavelength conversion. The experimental results show error-free operation with reshaping and regeneration leading to negative power penalty for signals with impaired signal-to-noise and extinction ratios. While the experiment was conducted on a single wavelength channel, a multiwavelength optical label switching system can incorporate this technique in parallel. The 2R regeneration in the all-optical label-swapping subsystem implies its viability in a scalable optical-label switching network.

Performance monitoring in transparent optical networks using self-monitoring optical-labels

A novel optical layer performance monitoring method in transparent optical-label switching networks is presented. It is based on the signal quality correlation between the data payload and the label, which allows monitoring of the data payload signal quality by monitoring the label bit error rates. Experimental results indicate effective estimations of payload data bit error rates over approximately a 15 dB dynamic range of signal-to-noise ratio.

Demonstration of all-optical packet switching routers with optical label swapping and 2R regeneration for scalable optical label switching network applications

This paper investigates comprehensive operation and experimentation of an all-optical packet switching router with optical label swapping and reamplification and reshaping (2R) regeneration, capable of multihop operation and Internet protocol (IP)-client interoperability. In particular, the experiment demonstrates successful packet switching and transport up to 11 hops with 10/sup -9/ bit-error rate and error-free up to four hops. Furthermore, this paper demonstrates the optical label switching (OLS) core router and edge routers working together to support IP-client-to-IP-client packet transport and switching across the optical label switching network. The edge router generates an optical label based on the IP header content of the packet and generates an optical label encoded packet, which subsequently ingresses into the OLS network. The optical label switching router (OLSR) forwards the packet with all-optical label swapping at each hop with 2R regeneration. The 2R regeneration leads to an experimentally measured negative penalty and a successful experimental demonstration of multihop cascaded OLSR operation with the edge routers interfacing with IP clients. The successful IP-client-to-IP-client packet forwarding via the edge routers and the cascaded multihop OLSR with all-optical label swapping indicate the viability of OLS in the scalable and transparent IP-over-optical Internet.

Performance of Manchester-coded payload in an optical FSK labeling scheme

The modulation crosstalk between combined frequency-shift keying (FSK) and intensity modulation (IM) in an optical label-switching network is analyzed both theoretically and experimentally. A comparison between the performance of nonreturn-to-zero (NRZ) and Manchester-coded payload is made. It is shown that Manchester coding of the payload helps to suppress the crosstalk introduced into the optical FSK label, thus achieving better network performance than NRZ coding.

Traffic engineering in multigranularity heterogeneous optical WDM mesh networks through dynamic traffic grooming

In this article we investigate the problem of efficiently provisioning connections of different bandwidth granularities in a heterogeneous WDM mesh network through dynamic traffic grooming schemes under traffic engineering principles. Due to the huge amount of traffic a WDM backbone network can support and the large geographic area it can cover, constructing and upgrading such an optical WDM network can be costly. Hence, it is extremely important for network operators to apply traffic engineering strategies to cost-effectively support different bandwidth granularity services using only the appropriate amount of network resources. This requires an optical WDM network to have multigranularity switching capability, and such a network tends to be a multivendor heterogeneous network. However, WDM network heterogeneity increases the difficulty and challenge of efficient traffic provisioning. In this article we present different TE issues that need to be carefully considered in such an optical WDM network, and propose possible solutions and extensions for the generalized multiprotocol label switching optical network control plane. We extend an existing generic graph model to perform efficient traffic grooming and achieve different TE objectives through simple shortest path computation algorithms. We show that our approach is very practical and very suitable for traffic engineering in a heterogeneous multigranularity optical WDM mesh network.

On Architecture and Limitation of Optical Multiprotocol Label Switching (MPLS) Networks Using Optical-Orthogonal-Code (OOC)/Wavelength Label

To accommodate the explosive packet-based data traffic in WDM networks, intelligent optical routing and switching are required in optical transport networks. Optical multiprotocol label switching networks emerged to meet this demand. In this paper, different schemes for implementing an OMPLS network are introduced. An optical MPLS network using OOC/wavelengths as labels is proposed. Based on an all-optical code converter, the architecture of the optical core router is demonstrated. The fundamental limits on scalability of the proposed core router, namely the label capacity, and the blocking probability of the label switched path setup are investigated, and closed-form solutions are derived.

Label-switching architecture for IP traffic over WDM networks

The paper focuses on the architecture of running IP traffic directly in a DWDM network using label switching which effectively simplifies the protocol layers between the IP and the DWDM network backbone. A label-switching optical network architecture based on multiple protocol label switching for routing and label assignment is proposed. The performance evaluation for the proposed network architecture focuses on the effects of IP traffic load, the burst nature of IP traffic and the interchannel interference caused by the fibre nonlinear four-wave mixing. Numerical results including IP packet error probability and high-order distribution functions of IP packet error such as IP packet free-run distribution and IP packet error pattern distribution are presented in terms of IP traffic load, input light signal power and the frequency space between the optical wavelengths. These results provide useful reference and estimation to system designers.