Scalable routing, scheduling and virtualization for TWIN optical burst switching networks

In this paper, we compare the cost of the survivable optical transport solutions with subwavelength switching gran-ularity. The focus is on Time-Domain Wavelength Interleaved Network (TWIN) and Packet Optical Add/Drop Multiplexer (POADM) network. Both technologies exploit optical slot switching: TWIN on a physical mesh topology, and POADM on a physical ring. The cost model accounts for the node components, the transponder cost and the cost of wavelength use per km of fiber. For the first time, a single network dimensioning model supporting protection is proposed for these metro technologies. The network planning solution is based on linear programming, and addresses the routing and wavelength assignment problem (RWA) and the optimal scheduler calculation. We consider dedicated protection, which consist in doubling the capacity of each operational conthe network and shared protection, in which the protection capacity is potentially shared between multiple backup flows. By running the linear programming optimization we study the impact of different protection models on the cost of networks in different configurations and identify the scenarios for which each of the technologies is best suited.

Existing methods for handling routing and dimensioning in dynamic WDM networks solve the two problems separately. The main drawback of this approach is that a global minimum cost solution cannot be guaranteed. Given that wavelengths are costly resources, determining the minimum network cost is of fundamental importance. We propose an approach which jointly solves the routing and dimensioning problems in optical burst switching (OBS) networks, guaranteeing a target blocking per connection. The method finds the set of routes and the number of wavelengths per network link that minimise the total network cost. To accomplish this, an integer linear programming problem is solved. The proposed method was applied to ring networks, where the optimal solution achieves a reduction in the network cost of 10–40% (for traffic loads <0.4, compared to solving both problems separately). In the case of mesh topologies, to reduce the computational complexity of the method, we applied a variation of it which achieves a local minimum. Even so, a reduction of 5–20% (for traffic loads <0.4) in the network cost was obtained. This ability to lower network cost could make the proposed method the best choice to date for dynamic network operators.

Optical burst switching (OBS) is a new optical switching paradigm where traffic can be switched and groomed at a lower level compared to optical switched circuit (OCS). While OCS is useful in carrying highly aggregated long-lived streams that require absolute quality of service (QoS) guarantees, OBS has a role in efficiently carrying bursty best-effort traffic. In this paper, we investigate further the comparative goodput and bandwidth efficiency of OBS and OCS using, on one hand, an adaptive deflection OBS routing that aims at minimizing the burst loss rate and, on the other hand, a routing and wavelength OCS strategy using the best possible routing paths for minimizing the blocking rate.

In WDM networks, static Routing Wavelength Assignment (RWA) problem is NP-complete. The Integer Linear Programming (ILP) is too complicated to implement. In most existing algorithms, it is usually split into routing and wavelength assignment, which is not completely precise. Mainly motivated by that imprecision, the Layered-Graph model was introduced into static RWA problem, which can consider the routing and wavelength assignment jointly. Three proposed algorithms using this model are described in this paper. Their performances are also evaluated by series of exhaustive simulations.

Optical burst switching (OBS) supports IP-over-photonics for future QoS-supporting Internet through combining advantages of electronic control processing and optical transmission. The resource reservation is critical for OBS. In this paper we examine optical burst switching (OBS) reservation process and discuss the most important parameters and their impact on the performance of the reservation process. A general framework for its modeling and analysis is presented. We model OBS reservation using queueing networks. Our framework and model cover all aspects of OBS reservation process including control packet arrival, offset time assignment. control packet processing, optical switch matrix setup, data burst arrival and transmission. Current models and analysis only consider offset time assignment and data burst arrival and transmission its OBS reservation. Further we show that even though widely assumed and used, conservation law does not hold generally for average burst loss probability for reservation processes which support multiple priority classes.

Optical burst switching (OBS) technology is a promising solution for the next generation Internet backbone. However, contention resolution and QoS support constitute critical issues in its services development. We propose in this paper a novel architecture for optical networks suitable for OBS switching, contention resolution, and QoS provisioning. The performance evaluation is realized based on an ad-hoc analytic model and a simulation. The method proposed is based on the re-design of optical switches to include optical delays lines and adapting the signaling protocol.

Among the promising solutions for next generation Internet backbones, one can consider the optical burst switching (OBS) technology. The deployment of the OBS technology needs to address dimensioning and resources optimization issues that constitute an essential task in the development of OBS services. In this paper, we propose a QoS-based approach to address these issues in the development of OBS networks. An analytic model is developed for network resources dimensioning and optimization problems' formulation. A simulation model is developed to validate the proposed approach, and to study the impacts of some key input system parameters on the optimal network configuration.

Optical burst switching (OBS) is regarded as a promising optical switching paradigm for next generation optical Internet. More and more real-time traffic is transported by IP and it is important for OBS to support real-time traffic. Based on the delay analysis of OBS networks, a pipeline scheme is proposed to reduce the delay and efficiently support real-time traffic for OBS networks in the paper. When real-time traffic is transported in the core nodes of the established pipeline and its burst head packet can not need to be processed. So the pipeline scheme reduces the offset time and delay of realtime traffic. The simulation result shows that the pipeline scheme effectively reduces the end-to-end delay of real-time traffic in the OBS networks.

Optical burst switching (OBS) has been proposed as the next generation optical network for grid computing. In this paper, we envision a heterogeneous Grid served by an Optical Burst Switching framework, where grid traffic co-exists with IP and/or a 10 GE based traffic to achieve economy of scale. This paper addresses the latency that Grid jobs experience in OBS networks. The injection of jumbo size grid jobs can potentially affect the latency experienced by IP/10GE traffic. Simulation results have shown that in Grids served by an optical burst switch, grid jobs consistently have lower latency than co-existing IP/10GE traffic, with a slightly elevated latency of IP/10GE traffic when the size of grid jobs increases. We conclude that given the fact that OBS can efficiently handle the enormous amount of bandwidth made available by DWDM technology, Grid over Optical Burst Switching is a cost effective way to provide grid services, even for latency sensitive grid computing applications.

In this paper, we propose a protocol architecture and quality of service (QoS) supporting algorithms for optical Internet based on optical burst switching (OBS) technology. Firstly, the function of each layer of the protocol architecture and the formats of control packets are defined in order to adopt GMPLS to the control plane of OBS. Then, the offset time decision (OTD) algorithm to cooperate with the proposed protocol architecture is designed for optical Internet. A new burst loss formula taking into account the effect of offset time is introduced to design the OTD algorithm. This algorithm can decide on the appropriate “priority-offset” time according to the required QoS by using the reversed equation of the so-called heuristic loss formula (HLF) which is approximated as a proportional equation of our new loss formula. Finally, we propose a CAC algorithm based on the OTD algorithm for the purpose of increasing the availability of wavelength resources and supporting the QoS of established connections in optical Internet. The performance of the proposed algorithms is evaluated in terms of burst loss rate and the number of connections through simulation.

Optical Circuit Switching (OCS) provides a good support for the services requiring high bandwidth and Quality of Service (QoS). When the character of network traffic changes from voice-oriented to data-oriented, OCS must cooperate with new switching mechanisms such as Optical Burst Switching (OBS) to improve performance. So a Hybrid Optical Switching (HOS) system is proposed. In HOS, different traffics are classified and both OBS and OCS can be processed. At the same time, delay buffer mechanisms, which are Fiber Delay Line (FDL) and electronic buffering, are introduced in HOS to solve the contention of OBS bursts. And a wavelengths classification mechanism, which assigns some wavelengths dedicated to OCS traffics, is provided to guarantee the QoS of OCS. To analyze the performance in theory, models based on Markovian theory and iterative method are provided. The results got by theory are accurate compared with simulations. The use of delay buffer can decrease the blocking probability of OBS and increase resource utilization. Wavelength classification mechanism benefits to improve OCS's performance.

Topology-aware wavelength partitioning for DWDM OBS networks: A novel approach for absolute QoS provisioning

Optical burst switching (OBS) is a switching technology that can efficiently operate in the optical core network using WDM technology and can also develop the future optical internet. The OBS switching technology presents a trade-off between the two switching technologies: optical circuit switching (OCS) and optical packet switching (OPS). This switching approach increases resource utilization compared with OCS technology and avoids the technological barriers of OPS networks. In OBS networks, many packets are assembled into one data burst at the edge node and a burst header packet (BHP) is sent before the burst transmission by an offset time in order to reserve the required resources in core nodes. This can cause security issues in the network and more specifically denial of service attacks that can occur if a source node is compromised. In this paper, we study a specific denial of service attack which we refer to as "BHP flooding attack", which prevents legitimate traffics from reserving the required resources at intermediate core nodes. We also propose the design of a reconfigurable BHP flooding countermeasure module that allows to counter against this type of attacks in an OBS network.

On burst assembly in optical burst switching networks—A performance evaluation of just-enough-time

Enhanced packet routing queuing model in optical burst switching network using queue-based dynamic optical route scheduling