域间流量工程的研究与实现

域间的流量工程策略有助于保证业务流的端到端QoS、提高网络资源利用率并实施跨域的快速恢复.本文介绍了域间流量工程的研究现状,并详细分析了不同的实现方法.最后指出了实施域间流量工程的困难所在及以后的研究方向.     

基于MPLS的Internet流量工程研究

Internet流量工程是控制流量怎样流经 Internet网络以优化资源利用和网络性能的过程 ,是确保端到端 Qo S的重要技术。本文归纳出了 Internet流量工程的通用加工模型 ,流量预测采用的方法和格式 ,并对域间流量工程的实现技术进行了探讨     

基于MPLS的Internet流量工程研究

Internet流量工程是控制流量怎样流经Internet网络以优化资源利用和网络性能的过程，是确保端到端QoS的重要技术。本文归纳出了Internet流量工程的通用加工模型，流量预测采用的方法和格式，并对域间流量工程的实现技术进行了探讨。     

基于MPLS的Internet流量工程研究

Internet流量工程是控制流量怎样流经Internet网络才能优化资源利用和网络性能的过程，是确保端到端QoS的重要技术。本文归纳出了Internet流量工程的通用加工模型以及流量预测采用的方法和格式，并对域问流量工程的实现技术进行了探讨。     

BGP路由服务平台(RSP)的设计

目前自治域间的路由协议-边界网关协议(BGP)存在许多问题:全互联结构无法适应大规模网络,路由反射可能带来协议振荡和路由环路。文章分析了这些问题并给出了支持域间流量工程的BGP路由服务平台的设计。     

下一代光互联网域间流量疏导解决方案

目前的互联网中,端到端(P2P)应用模式的出现及其广泛应用可能将改变网络的流量模式,对于传统的传送网络结构带来了新的挑战,需要从业务、网络控制和传送层面共同规划.采用协议与算法相结合的方式进行流量疏导,扩展传统多粒度概念,给出综合的域间网络规划解决思路.     

基于SDN的互联网域间路由研究

互联网流量的爆发式增长,叠加互联网流量固有的突发性特点,使得网络流量不均衡现象日益加剧。传统BGP协议由于缺乏全网拓扑和全局流量观,只能遵循标准BGP选路原则,在解决流量调度和负载均衡方面存在不足。针对BGP协议存在的局限性,研发了基于RR+的互联网骨干网流量调度系统,并应用于ChinaNet骨干网的网内中继、网间互联出口、IDC出口等多个流量优化场景。更进一步地,提出了一种基于SDN的互联网域间路由架构,通过在域间控制器之间交换BGP路由,无需在域内和域间运行BGP协议,极大地简化了网络协议,并能够实现灵活的流量调度和负载均衡。     

IMS网络端到端QoS控制机制研究

IMS网络的端到端QoS控制技术是目前研究的热点,文中阐述了基于策略的网络管理架构在IMS网络中的应用,并深入研究了IMS网络不同层次间相互协作实现QoS技术和多域环境下的端到端QoS管理的策略控制结构.     

基于遗传算法的域间流量控制

针对域间流量特点，提出一种基于前缀的域间流量控制算法。利用遗传算法求解出传输自治系统中不同前缀的出口选择和域内各条链路的OSPF权重的优化解，再利用边界网关协议(BGP)对不同的前缀进行相应的通告来控制域间出流量，使域间流量分布更合理。     

基于LSP平衡的流量分配机制研究

对尽力而为（BE）网络流量工程中的自适应流量分配问题进行了深入研究,引入了一种平衡思想,提出一种基于LSP平衡的流量分配（LE-TD）机制,对网络中的流量进行网络平衡规划,利用需求和代价的平衡,使整个网络达到一种稳态,从而使网络中流量的分布模式是稳定的。仿真表明,该机制具有稳定性和收敛性,能有效地实现流量在多条并行LSP之间的合理分配,能有效提高网络端到端平均吞吐量,降低网络端到端平均时延,从而有效地实现了流量工程的优化目标。     

GATEway: symbiotic inter-domain traffic engineering

There are a group of problems in networking that can most naturally be described as optimization problems (network design, traffic engineering, etc.). There has been a great deal of research devoted to solving these problems, but this research has been concentrated on intra-domain problems where one network operator has complete information and control. An emerging field is inter-domain engineering, for instance, traffic engineering between large autonomous networks. Extending intra-domain optimization techniques to inter-domain problems is often impossible without the information available within a domain, and providers are often unwilling to share such information. This paper presents an alternative: we propose a method for traffic engineering that does not require sharing of important information across domains. The method extends the idea of genetic algorithms to allow symbiotic evolution between two parties. Both parties may improve their performance without revealing their data, other than what would be easily observed in any case. We show the method provides large reductions in network congestion, close to the optimal shortest path routing across a pair of networks. The results are highly robust to measurement noise, the method is very flexible, and it can be applied using existing routing.     

Performance Analysis of Infrastructure Service Provision with GMPLS-Based Traffic Engineering

Dynamic sharing of the common physical network is envisioned as a key enabler for the emerging Internet technologies. This paper addresses challenges related to resource sharing in the physical layer and analyzes the performance of infrastructure service provision with control plane mechanisms based on generalized multi protocol label switching (GMPLS). In our approach, the provisioning of infrastructure services is supported by two novel concepts for GMPLS traffic engineering (TE): resource visibility and inter-domain exchange. Resource visibility is a new network control plane concept, which defines the usage polices for transmission, multiplexing, and switching resources in multiple GMPLS layers. In our architecture, every network resource may exhibit different visibility to different services at different layers. The inter-domain exchange, here referred to as GMPLS exchange point (GXP), is the physical layer equivalent of the Internet exchange point (IXP). Just as how the IXP manages interconnections of autonomous systems (AS) in the Internet, the GXP manages dynamic interconnections of multiple provider domains and enables them to advertise their physical resources to other domains. We model the dynamic provisioning of infrastructure services using graph theory and deploy GMPLS traffic engineering (TE) to optimize the routing and resource yields. The results obtained demonstrate that traffic engineering with resource visibility and GXP brings significant performance benefits in resource utilization and infrastructure extensibility, especially when network providers set up LSPs as a result of collaborative and carrier-neutral traffic engineering where they share information about resource capabilities and utilization     

Topics in Optical Communications - Operational Evaluation of ASON/GMPLS Interdomain Capability over a JGN II Network Testbed

Traffic engineering in backbone networks is an important issue in supporting an appropriate QoS level to accommodate various types of traffic flows efficiently. Automatically switched optical networks and generalized multiprotocol label switching control planes are promising functionalities to achieve the sophisticated mechanism of interdomain traffic engineering. In this article we address dynamic operational scenarios to control IP traffic flows using the ASON/GMPLS control plane. This includes cut-through IP/MPLS routers and the rerouting of failed links through the tunnel of optical label-switched paths. This article presents an operational evaluation of traffic engineering. More specifically, we present QoS recovery for protecting high priority traffic using policy controllers and fault recovery of inter-domain LSPs over the JGN II network testbed. This article evaluates and discusses the feasibility of these operational scenarios using state-of-the-art optical switching and control- plane technologies.     

SDI: a multi-domain SDN mechanism for fine-grained inter-domain routing

Software-defined networking (SDN) scheme decouples network control plane and data plane, which can improve the flexibility of traffic management in networks. OpenFlow is a promising implementation instance of SDN scheme and has been applied to enterprise networks and data center networks in practice. However, it has less effort to spread SDN control scheme over the Internet to conquer the ossification of inter-domain routing. In this paper, we further innovate to the SDN inter-domain routing inspired by the OpenFlow protocol. We apply SDN flow-based routing control to inter-domain routing and propose a fine-granularity inter-domain routing mechanism, named SDI (Software Defined Inter-domain routing). It enables inter-domain routing to support the flexible routing policy by matching multiple fields of IP packet header. We also propose a method to reduce redundant flow entries for inter-domain settings. And, we implement a prototype and deploy it on a multi-domain testbed.     

A novel segment-shared protection algorithm based on dynamic domain-sequencing scheme for multi-domain optical mesh networks

Survivability has been widely recognized as an important design issue for optical networks. In practice, as the network scale keeps expanding, this design problem becomes more critical. Due to scalability and domain privacy, designing the protection scheme in multi-domain networks is more difficult than that in single domain networks. The path computation element (PCE) is known as an efficient architecture to compute optimal traffic engineering (TE) paths in multi-domain multilayer networks. Based on the PCE architecture, we first propose a new dynamic domain-sequencing scheme that considers the load balance of inter-domain links and then propose an improved segment-shared protection approach called DDSP. It can provide 100% protection ability for multiple failures that each single domain has only one failed link. Finally, the protection based on the optimal dynamic domain-sequencing scheme, called OPT, is designed, to evaluate performance of our algorithm and to provide the good bounding for the dynamic domain-sequencing scheme with limited intra TE information. Simulation evaluation shows that the proposed scheme is effective in multi-domain path protection with more efficient resource utilization, lower blocking probabilities and less inter-domain cost. Furthermore, the performance of it is near to OPT.     

P-cycle Protection in multi-domain optical networks

Providing resilient inter-domain connections in multi-domain optical GMPLS networks is a challenge. On the one hand, the integration of different GMPLS domains to run traffic engineering operations requires the development of a framework for inter-domain routing and control of connections, while keeping the internal structure and available resources of the domains undisclosed to the other operators. On the other hand, the definition of mechanisms to take advantage of such automatically switched inter-domain connectivity is still an open issue. This article focuses on the analysis of applicability of one of these mechanisms: P-cycle-based protection. The proposed solution is based on the decomposition of the multi-domain resilience problem into two sub-problems, namely, the higher level inter-domain protection and the lower level intra-domain protection. Building a P-cycle at the higher level is accomplished by certain tasks at the lower level, including straddling link connection, capacity allocation and path selection. In this article, we present several methods to realize inter-domain P-cycle protection at both levels and we evaluate their performance in terms of availability and spent resources. A discussion on a proposal of implementation of signalling based on extensions of existing protocols such as RSVP-TE and the PCE architecture illustrates the practical viability of the approach.

A novel domain-by-domain survivable mechanism in multi-domain wavelength-division-multiplexing optical networks

In multi-domain wavelength-division-multiplexing (WDM) optical networks, the inter-domain routing is a challenge since each single-domain cannot view the full network topology. At the same time, survivability is also an important issue in optical networks since the failures of fiber links or network nodes may lead to a lot of traffic being blocked. In this paper, we study the survivability in multi-domain WDM optical networks, and propose a new survivable mechanism called load balanced domain-by-domain routing (LBDDR). In LBDDR, in order to obtain the efficient inter-domain survivable routes, we present the domain-by-domain routing (DDR) method which can find the intra-domain sub-working path and sub-backup path in each single-domain to form the inter-domain working path and backup path for each demand. In order to reduce the blocking probability, we present the load balanced routing method which can encourage the traffic to be uniformly distributed on the links with more free wavelengths. Simulation results show that, compared with conventional mechanism, LBDDR can obtain better performances.