A new optical label scheme called Common optical SCM (Subcarrier Multiplexing) label method is proposed. The label paths are consisting of multiplex SCM paths with SCM/WDM technology, which separate from the data wavelength paths. These label paths are parallel and shared for any data wavelength path. We analyzed the modulation and transmission of SCM label channels and compared the bandwidth efficiency and switching performance of main several optical label schemes. The results show that because of no guard between label and data packets the bandwidth efficiency increases and the operation complexity decreases in common optical label schemes and multiple shared parallel SCM label channels can decrease the block probability of label packets.
In Optical burst switching (OBS) networks, one important issue is how the performance will be affected by burst assembled from packets. In this paper, we study the fundamental statistic properties of Possion and Pareto traffic, such burst length distribution, inter-arrival time distribution and the switching performance with different aggregation schemes. The results show that the traffic will approach the Gaussian distribution of both kinds of traffic, but the aggregation operation has little effect on the heavy tail of Long Range Dependent traffic. The aggregation algorithm based on aggregation time degrades the loss performance of burst switch because burst arrivals easily concentrate a moment at the period of aggregation time window.
In this paper, a traffic-grooming problem for multi-granularity traffic of SDH/SONET in WDM grooming mesh networks is investigated. We propose a path select routing algorithm to solve this problem. The performances of this traffic grooming path select routing algorithm are evaluated in WDM grooming networks. Finally, we presented and compared the simulation results of this algorithm in dynamic traffic grooming WDM mesh networks with that of other algorithms.
In this paper, the objective was optimizing the port number with dynamic traffic grooming of SDH/SONET WDM mesh networks to give useful referenced data to networks design and the cost control of networks. The performances of different path select routing algorithms were evaluated in WDM grooming networks by considering traffic of different bandwidth requests. Finally, the results were presented and compared with in distributed-controlled WDM mesh networks.
A new loop output buffer architecture for optical packet switching is proposed. It is consisted of multiplex FDL loops, which are divided into k stages by k (M+1) x (M+1) switches. Using this architecture, a few FDL loops can provide large optical memories and get good packet-loss performance, and the delay performance can be improved by adding switches and buffer scheduling.
In this paper, the dynamic distributed traffic-grooming problem in WDM optical mesh network is investigated. We give the proposal of the number optimization of wavelengths and ports are evaluated in a class of IP/WDM distributed nteworks. We presented and compared the performances of dynamic distributed traffic grooming in regular and irregular optical mesh networks, and give the optimized number of wavelengths and ports in different network condition.
Wavelength-division multiplexing appears to be the solution of choice for providing a faster networking infrastructure that can meet the explosive growth of the Internet. Future networks are expected to utilize the WDM technology for optical functionalities capable of handling multi-Teragabit signals and thus the cost, therefore it is very important that the Optical cross-connects (OXCs) and optical Add-drop Multiplexers (OADMs) have performed routing and switching capacities. Optical Packet Switch (OPS) technology allows us to rapidly deliver the enormous network bandwidth. OPS offers high-speed data rate and format transparency. But there are still many technologies and key components need to solve. In this paper we propose a novel architecture for OPS using Tunable Wavelength Converters (TWC) and Fiber Delay-Lines (FDLs). We use wavelength converters and demuxes connected with several FDLs that provide different delay periods. Input wavelengths can be tuned to different ones in order to acquire different delay periods. Wavelength converters are shown to improve the traffic performance of the switch blocks for both random and burst traffic. It can also provide contention resolution solution in wavelength and time domains. This architecture improves packet switching speed and significantly decreases the use of optical switches comparing with general architecture. Finally, the simulation results show that the packet blocking can be decreased.
The realization technology of a new kind of multi-wavelengths label optical packet switching technology is discussed. In this switching, optical header is labeled by several optical pulses at different wavelengths in the same optical communication channel band as optical payload. The optical transmitter with header generation and packet formation, receiver with data restoration and switching node with route processing are introduced. The switching principle is verified by a simplified experiment.
Optical Label Switching (OLS) is one of the practical manners of optical packet switching. It is a main research domain in optical networks. The advantage of OLS is its bandwidth efficiency and ability to support various network devices. There are a lot of practical problems need to be resolved. Today, research into OLS technology has focused on key networking and hardware issues such as high-speed optical switch, optical storage component, and network nodes source distribution optimization algorithm. The optical Label Header contains header synchronizing bits, routing address bits, etc. Header reading and rewriting includes synchronizing, routing and checking technologies. So it is the key issue in the OLS, and has very important research and application values. In this paper, a novel proposed fabric scheme was discussed to achieve the function of the header reading and rewriting. It can be applied to the high-speed header reading and rewriting to satisfy the requirements of practical applications. The fabric scheme adopts a high-speed tunable laser and wavelength converter to rewrite the header. The high-speed tunable laser is based on Grated Coupler Sampled Reflector (GCSR) structure and the wavelength converter is based on Cross-Phase Modulation (XPM) in a Semiconductor Optical Amplifier (SOA) and a Mach-Zehnder Interferometer (MZI) structure. The synchronization of the packet in the node also be discussed.
Using the feature that the gain peak wavelength only depends on the pump wavelength, the multi-pump sources and their gain peak wavelengths can be considered as the input and output variables of the single layer feed-forward neural networks, and the optimal design for multi-pumped Raman Fiber Amplifier can be converted to a optimal problem of the single layer feed-forward neural networks. With the optimal algorithm the Raman gain spectra of multi-pumped FRAs were investigated. The results show that the optimal configuring algorithm is simple and effective.
The most important feature of Raman gain spectrum is that the gain peak wavelength only depends on the pump wavelength (fixed shift about 100nm). Using the gain values of these gain peak wavelengths we can determine how to adjust power and intervals of pumps until the optimal result is made. In this paper, using the peak wavelength gain optimal method and a comprehensive model the Raman gain spectra of multi-pumped FRAs under the various conditions were investigated. The results show that controlling the pump sources power and wavelength intervals can optimize the bandwidth and flatness of gain spectrum. The optimal configuring method for the multi-pump sources of distributed FRAs is simple and effective.
Optical layer networking and survivability are very important branches of the study of optical communication network. Recent standards proposals have focused on extending MPLS protocols to manage optical network resources. These proposals have concentrated on provisioning optical connections and offering restoration capability in mesh optical networks. Few papers, however, are concentrated on protection issues of backup path. By considering the protection of backup path, survivability of protection scheme will improve. This article presents a novel paradigm enhancing the existing pre-established protection schemes using Multi-Protocol Lambda Switching architecture and demonstrates local restoration and global restoration for backup path with examples. Finally, we discuss the advantages of this approach and present future work.
Using a comprehensive model that includes pump-to-pump, pump-to-signal, signal-to-signal interaction, Rayleigh scattering and amplified spontaneous emission the Raman gain spectra of multi-pumped Raman amplifier under the various conditions were investigated. The results show that a different pump powers and pump wavelength intervals schemes are required for multi-pumped Raman amplifier. To obtain broader bandwidth and smaller gain ripple the powers of the shorter and longest wavelength pumps are needed higher power and the powers of the middle wavelength pumps should be set lower.