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1.
The combination of high capacity, signal robustness, and worldwide acceptance have made digital terrestrial broadcasting (DVB-T) one of today's more promising technologies, while newly adopted standards support the integration of digital television programs and data services within a single multiplex, offered to both stationary and mobile end users. The paper addresses the issue of optimal bit rate allocation among DTV and IP services within the DVB-T multiplex, and demonstrates a novel configuration providing real-time sharing of the available bandwidth via an algorithm based on service hierarchy and perceptual quality assessment. The architecture and performance of a fully functional DVB-T testbed developed on this concept is also presented. 相似文献
2.
《Optical Switching and Networking》2008,5(2-3):170-176
IP-over-WDM networks are starting to replace legacy telecommunications infrastructure and they form a promising solution for next-generation networks (NGNs). Survivability of an IP-over-WDM network is gaining increasing interest from both the Internet research community and service providers (SPs). We consider a novel static bandwidth-provisioning algorithm to support differentiated services in a survivable IP-over-WDM network. We propose and investigate the characteristics of both integer linear program (ILP) and heuristic approaches to solve this problem. In the heuristic method, we propose backup reprovisioning to ensure network resilience against single-node or multiple-link failures. Illustrative examples compare and evaluate the performance of the two methods in terms of capacity-usage efficiency and computation time. 相似文献
3.
Quality-of-service mechanisms in IP-over-WDM networks 总被引:3,自引:0,他引:3
Classical approaches to QoS provisioning in IP networks are difficult to apply in all-optical networks. This is mainly because there is no optical counterpart to the store-and-forward model that mandates the use of buffers for queuing packets during contention for bandwidth in electronic packet switches. Since plain IP assumes a best effort service model, there is a need to devise mechanisms for QoS provisioning in IP over wavelength-division multiplexing networks. Such mechanisms must consider the physical characteristics and limitations of the optical domain. This article presents a classification and survey of proposals for QoS provisioning and enforcement in IP-over-WDM networks. The different QoS proposals surveyed cover three major optical switching methods: wavelength routing, optical packet switching, and optical burst switching. 相似文献
4.
A management and control architecture for providing IPdifferentiated services in MPLS-based networks
Trimintzios P. Andrikopoulos I. Pavlou G. Flegkas P. Griffin D. Georgatsos P. Goderis D. T'Joens Y. Georgiadis L. Jacquenet C. Egan R. 《Communications Magazine, IEEE》2001,39(5):80-88
As the Internet evolves toward the global multiservice network of the future, a key consideration is support for services with guaranteed quality of service. The proposed differentiated services framework is seen as the key technology to achieve this. DiffServ currently concentrates on control/data plane mechanisms to support QoS, but also recognizes the need for management plane aspects through the bandwidth broker. In this article we propose a model and architectural framework for supporting DiffServ-based end-to-end QoS in the Internet, assuming underlying MPLS-based explicit routed paths. The proposed integrated management and control architecture will allow providers to offer both quantitative and qualitative services while optimizing the use of underlying network resources 相似文献
5.
Yining Cao Hongyi Xie Xiaoping Zheng Yanhe Li Hanyi Zhang 《Photonic Network Communications》2009,18(2):211-217
In this article, we consider the capacity fairness problem in IP-over-WDM networks. Since connections with different bandwidth
granularities may be established over a shared lightpath, fairness in bandwidth allocation among different users becomes a
crucial problem. A simple, yet efficient hop constraint-based admission control scheme is proposed to accommodate more high-bandwidth
requests. Through rejecting some of the low-capacity requests that would go through alternative paths with more hops and thus
would consume a larger amount of bandwidth, the blocking probability of high-capacity requests reduces notably. Numerical
results show that this proposal achieves significant improvement in capacity fairness without raising the overall blocking
probability. In addition, it achieves excellent fairness performance at both light and heavy loads by selecting the rejection
probability dynamically.
相似文献
Yining CaoEmail: Email: |
6.
Performance evaluation of two bandwidth allocation strategies in wireless mobile integrated services networks is carried out.
Performances of the proposed strategies are compared with those of the traditional guard channels and threshold strategies.
In the study, a single wireless cell which is accessed by voice and non-voice traffic types producing, respectively narrowband
and wideband calls is considered. In the proposed strategies a number of channels are reserved in a fixed or dynamic fashion
for the use of originating wideband calls in addition to the guard channels allocated for the handoff calls. The results indicate
that the two strategies have comparable advantages and by manipulating the number of reserved channels, desired performance
levels can be achieved. The dynamic reservation based strategy makes the system fairer for the originating wideband calls
while maintaining low handoff dropping probability and acceptable channel utilization levels. On the other hand, the fixed
reservation strategy provides a lower handoff call dropping at comparable channel utilization levels. The tradeoff is between
improving the handoff call dropping versus the originating wideband call blocking. Both strategies provide better performance
for the originating wideband calls compared with that provided by the traditional guard channels strategy.
相似文献
Dervis Z. DenizEmail: |
7.
8.
QoS performance of optical burst switching in IP-over-WDM networks 总被引:31,自引:0,他引:31
Myungsik Yoo Chunming Qiao Sudhir Dixit 《Selected Areas in Communications, IEEE Journal on》2000,18(10):2062-2071
We address the issue of how to provide basic quality of service (QoS) in optical burst-switched WDM networks with limited fiber delay lines (FDLs). Unlike existing buffer-based QoS schemes, the novel offset-time-based QoS scheme we study in this paper does not mandate any buffer for traffic isolation, but nevertheless can take advantage of FDLs to improve the QoS. This makes the proposed QoS scheme suitable for the next generation optical Internet. The offset times required for class isolation when making wavelength and FDL reservations are quantified, and the upper and lower bounds on the burst loss probability are analyzed. Simulations are also conducted to evaluate the QoS performance in terms of burst loss probability and queuing delay. We show that with limited FDLs, the offset-time-based QoS scheme can be very efficient in supporting basic QoS. 相似文献
9.
针对灵活栅格光网络中的业务公平性问题,提出业务分割-粗略分段(SS-RP)策略的频谱分配方案,其基本思想是将链路的频谱资源分为两部分,分别传输低速和高速业务,同时将高速业务分割成低速业务传输,以提高高速业务被服务的概率. 相似文献
10.
A practical approach for providing QoS in the Internet backbone 总被引:1,自引:0,他引:1
《Communications Magazine, IEEE》2002,40(12):56-62
This article describes a practical approach for providing quality of service in the Internet backbone. The approach considers both technical and economic factors. We first present network service provider (NSP) billing models and how NSPs provision their networks. We then analyze causes of QoS-related problems, and describe a practical approach for providing QoS. This approach makes use of good network design, differentiated services, traffic protection, traffic engineering, and traffic management techniques. The relative importance of these techniques is pointed out. Although this approach largely focuses on issues within a single NSP domain, if multiple NSPs adopt such an approach (or a similar approach), interdomain QoS can also be provided. 相似文献
11.
Given the extensive growth in Internet traffic and increasing emphasis on service quality, one of the most crucial elements of IP backbone network design is to provide resilience to serious failures such as fibre-optic cable breaks. In previous years, the unit of bandwidth granularity for many IP backbone networks has grown from STM-1 (155 Mbit/s) through to STM-16 (2.4 Gbit/s), with STM-64 (10 Gbit/s) backbone circuits becoming prevalent. The increased concentration of traffic makes the IP backbone extremely vulnerable to failure, meaning a key challenge is to engineer embedded resilience into the network. This paper considers such issues and discusses various trade-offs associated with different levels of protection in an IP backbone network 相似文献
12.
In this paper we design and study the performance of a Medium Access Control (MAC) scheme for the multiplexing and the integrated
delivery of voice, mobile messaging, IP, gaming and H.264 videoconference traffic over a high-speed cellular TDMA channel
with errors and capture. To the best of our knowledge, this is one of the first papers in the literature investigating the
integration of actual H.264 video traces and gaming traffic with other types of traffic over wireless networks. Our results
show that the proposed scheme achieves high throughput results while preserving the strict Quality of Service (QoS) requirements
of each traffic type, and outperforms two efficient schemes previously proposed in the literature. 相似文献
13.
Hongyi Xie Yanhe Li Xiaoping Zheng Xinyou Cui Yining Cao Hanyi Zhang 《Photonic Network Communications》2007,14(2):103-109
From both user and operator perspectives, fairness is an important aspect in IP-over-WDM networks where Label Switched Paths
(LSPs) are dynamically groomed over optical networks. The setup of LSPs with long distances experiences a higher blocking
probability due to both lightpath establishment unfairness in the optical layer and link cascading effect in the IP/MPLS layer.
A simple LSP connection admission and fairness control mechanism is proposed in this article. This control mechanism is based
on hop constraint, in which an LSP is accepted with a pre-assigned probability according to its distance and the hops of its
route. Through suppressing connection of short-distance LSPs that overuse bandwidth to facilitate the setup of LSPs with long
distances, this proposal achieves fine distance fairness performance with a slight overall blocking probability increment. 相似文献
14.
Differentiated services for wireless mesh backbone 总被引:1,自引:0,他引:1
《Communications Magazine, IEEE》2006,44(7):113-119
15.
16.
Sahasrabuddhe L. Ramamurthy S. Mukherjee B. 《Selected Areas in Communications, IEEE Journal on》2002,20(1):21-33
We consider an IP-over-WDM network in which network nodes employ optical crossconnects and IP routers. Nodes are connected by fibers to form a mesh topology. Any two IP routers in this network can be connected together by an all-optical wavelength-division multiplexing (WDM) channel, called a lightpath, and the collection of lightpaths that are set up form a virtual topology. In this paper, we concentrate on single fiber failures, since they are the predominant form of failures in optical networks. Since each lightpath is expected to operate at a rate of few gigabits per second, a fiber failure can cause a significant loss of bandwidth and revenue. Thus, the network designer must provide a fault-management technique that combats fiber failures. We consider two fault-management techniques in an IP-over-WDM network: (1) provide protection at the WDM layer (i.e., set up a backup lightpath for every primary lightpath) or (2) provide restoration at the IP layer (i.e., overprovision the network so that after a fiber failure, the network should still be able to carry all the traffic it was carrying before the fiber failure). We formulate these fault-management problems mathematically, develop heuristics to find efficient solutions in typical networks, and analyze their characteristics (e.g., maximum guaranteed network capacity in the event of a fiber failure and the recovery time) relative to each other 相似文献
17.
Addressing the interdependence in providing fair and efficient bandwidth distribution in hybrid optical‐wireless networks 下载免费PDF全文
Antonios Sarigiannidis Petros Nicopolitidis 《International Journal of Communication Systems》2016,29(10):1658-1682
The convergence of optical and wireless technologies may offer a compelling network access infrastructure because these technologies combine major benefits such as large coverage in the wireless part and huge bandwidth in the optical part of the converged access network. The convergence of the passive optical networks with 4G wireless standards, such as the Worldwide Interoperability for Microwave Access and the Long Term Evolution, constitutes a quite attractive solution to meet the challenges of the modern bandwidth‐hungry access networks. One of the most important objective a modern access network has to address is the adequate bandwidth distribution to the final users. In addition, several other aims are emerged towards this goal, such as fairness and quality of service provisioning. The adversity of designing an efficient bandwidth distribution scheme for hybrid optical‐wireless access networks lies in the interdependence of both domains: the bandwidth distribution in the wireless domain depends on the optical transmission grant opportunities, while the bandwidth coordinator in the optical part has to be aware of the mobile user heterogeneity in the wireless domain. Moreover, the bandwidth decision‐making module in both networks has to be aware of providing a fair allocation independently of the number of mobile users or the traffic requests in the network. In this work, we endeavor to address the aforementioned challenges. A novel, fair, and efficient bandwidth distribution scheme is proposed for hybrid optical‐wireless access networks. By using weighted fairness provisioning techniques, the proposed scheme intends to alleviate the interdependence of the two domains, offering a fair and efficient bandwidth distribution to the mobile users. The weights are properly defined, by utilizing suitable optimization techniques such as the Lagrange multiplies, so as to incorporate the underlying features of each traffic requests, such as the population density and the propagation delay. Extensive simulation results indicate the capability of the proposed scheme, compared with other competitive allocation schemes, in provisioning a more efficient and fair bandwidth distribution in terms of latency, throughput, and packet drop ratio. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
18.
Kam A.C. Kai-Yeung Siu Barry R.A. Swanson E.A. 《Selected Areas in Communications, IEEE Journal on》1998,16(7):1024-1039
Most existing wavelength-division multiplexed (WDM) networks employ circuit switching, typically with one session having exclusive use of one entire wavelength. Consequently, they are not suitable for data applications involving bursty traffic patterns. The All-Optical Network (AON) Consortium has developed an all-optical LAN/MAN test bed which provides time-slotted WDM service. We explore extensions of this service to achieve fine-grained statistical multiplexing with different virtual circuits time sharing the wavelengths in a fair manner. We develop a very fast, best effort time-slotted WDM network protocol with very good fairness and throughput characteristics. As an additional design feature, our protocol supports the assignment of guaranteed bandwidths (GBW) to selected sessions. This feature acts as a first step toward supporting integrated services at the optical layer in WDM networks 相似文献
19.
Fernando Lezama Gerardo Castañón Ana Maria Sarmiento Franco Callegati Walter Cerroni 《Photonic Network Communications》2014,28(3):306-319
In IP-over-wavelength division multiplexing networks, a virtual topology is placed over the physical topology of the optical network. Given that a simple link failure or a node failure on the physical topology can cause a significant loss of information, an important challenge is to make the routing of the virtual topology on to the physical topology survivable. This problem is known as survivable virtual topology mapping (SVTM) and is known to be an NP-complete problem. So far, this problem has been optimally solved for small instances by the application of integer linear programming and has been sub-optimally solved for more realistic instances by heuristic strategies such as ant colony optimization and genetic algorithms. In this paper, we introduce the application of differential evolution (DE) to solve the SVTM problem and enhancements based on DE are proposed as well. Three algorithms based on DE are developed. The enhanced variants have better convergence rate, get better quality of solutions and require few control parameters. We present the impact of these parameters on the system’s performance improvement. Algorithms are evaluated in different test bench optical networks, as NSFnet and USA, demonstrating that the enhanced DE algorithm overcomes the other two, for small instances. The three algorithms reach a 100 survivable mapping for small instances. The three algorithms also find positive survivable mappings and reduce the network wavelength links. Results show the effectiveness and efficiency of the proposed algorithms. 相似文献
20.
In this paper, we present a new traffic model constructed from a random number of shifting level processes (SLP) aggregated over time, in which the lengths of the active periods of the SLP are of Pareto or truncated Pareto distribution. For both cases, the model has been proved to be asymptotically second‐order self‐similar. However, based on extensive traffic data we collected from a backbone network, we find that the active periods of the constructing SLPs can be approximated better by a truncated Pareto distribution, instead of the Pareto distribution as assumed in existing traffic model constructions. The queueing problem of a single server fed with a traffic described by the model is equivalently converted to a problem with a traffic described by Norros' model. For the tail probability of the queue length distribution, an approximate expression and upper bound have been found in terms of large deviation estimates and are mathematically more tractable than existing results. The effectiveness of the traffic model and performance results are demonstrated by our simulations and experimental studies on a backbone network. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献