Evolution of multiprotocol label switching

Multiprotocol label switching (MPLS) is rapidly emerging as an Internet Engineering Task Force (IETF) standard intended to enhance the speed, scalability, and service provisioning capabilities in the Internet. MPLS uses the technique of packet forwarding based on labels, to enable the implementation of a simpler high-performance packet forwarding engine. This also decouples packet forwarding from routing, facilitating the provision of varied routing services independent of the packet forwarding paradigm. The authors track the evolution of this technology in relation to other existing technologies. Then an overview of the MPLS architecture and design is provided. In addition, some of the work that was a precursor to MPLS is discussed, as well as related issues and debates     

A perspective on photonic multiprotocol label switching

Various MPLS-based IP over WDM integration techniques are considered in this article. In particular, this includes the circuit-switching MPλS framework for providing logical IP-layer topologies over optical lightpath routing networks. Additionally, an optical code label switching technique for photonic packet switching and its application to MPLS is also introduced, termed OC-MPLS. The related advantages and challenges of both of these approaches are discussed, and various future research issues are addressed     

Generalized multiprotocol label switching: an overview of routingand management enhancements

Generalized multiprotocol label switching, also referred to as multiprotocol lambda switching, supports not only devices that perform packet switching, but also those that perform switching in the time, wavelength, and space domains. The development of GMPLS requires modifications to current signaling and routing protocols. It has also triggered the development of new protocols such as the Link Management protocol. We present the traffic engineering enhancements to the Open Shortest Path First Internet routing protocol and ISIS Intradomain Routing Protocol, two popular routing protocols, to support GMPLS. We present the concepts of generalized interfaces, label-switched path hierarchy, and link bundling intended to improve GMPLS scalability. We also discuss the Link Management Protocol which can be used to make the underlying links more manageable     

Generalized multiprotocol label switching: an overview of signalingenhancements and recovery techniques

Generalized multiprotocol label switching (GMPLS), also referred to as multiprotocol lambda switching, is a multipurpose control plane paradigm that supports not only devices that perform packet switching, but also devices that perform switching in the time, wavelength, and space domains. The development of GMPLS necessitates enhancements to existing IP signaling and routing protocols. We present enhancements to two commonly used IP signaling protocols, RSVP and LDP, to support GMPLS. We illustrate the concept of hierarchical label switched path setup with an example, discuss mechanisms for bidirectional LSP setup, and describe the applications of suggested labels. We also discuss the important problem of protection and restoration in the GMPLS context. Finally, we describe how various recovery mechanisms can be implemented within the GMPLS framework     

MPLS: the magic behind the myths [multiprotocol label switching]

This article reviews the key differences between traditional IP routing and the emerging multiprotocol label switching (MPLS) approach, and identifies where MPLS adds value to IP networking. In various corners of the industry MPLS has been held up as the solution to IP QoS, gigabit forwarding, network scaling, and traffic engineering. Each of these expectations is critically considered in the light of developments in conventional gigabit IP routers. It is shown that MPLS adds the ability to forward packets over arbitrary non-shortest paths, and emulate high-speed “tunnels” between IP-only domains-capabilities critical to service providers who need to better manage resources around their backbones, or who are planning IP VPN services. However, it is also argued that the technology required to support IP QoS and gigabit forwarding is not unique to MPLS. A network of gigabit IP routers or switches may be entirely sufficient for QoS and performance if traffic engineering is not a requirement     

Extending generalized multiprotocol label switching (GMPLS) for polymorphous, agile, and transparent optical networks (PATON)

This article presents a vision for the emerging integrated optical networks to meet various traffic requirements and design criteria. To address the shortcomings in today's GMPLS over wavelength-routed optical networks, a new network architecture called polymorphous, agile, and transparent optical networks (PATON) is proposed. PATON uses polymorphous optical burst switching (POBS) to seamlessly integrate different signaling, switching, and reservation schemes. The main features of PATON, along with its benefits as well as design and implementation challenges, are also described. Finally, both qualitative and quantitative performance comparisons of POBS with the two representative IP/GMPLS/OCS approaches are provided     

Protocol discovery in multiprotocol networks

Interoperability requires that communicating systems support compatible protocols. Maintaining compatible protocols is problematic in heterogeneous networks, especially in a wireless infrastructure where hosts can move from one protocol environment to another. It is possible to improve the flexibility of a communication network's operation by deploying systems that support multiple protocols. These multiprotocol systems require support mechanisms that enable users to effectively access the different protocols. Of particular importance is the need to determine which of several protocols to use for a given communication task. In this work, we propose architectures for a protocol discovery system that uses directory services and protocol feedback mechanisms to determine which protocols are supported. We describe the issues related to protocol discovery and present protocol features necessary to support multiprotocol systems. This revised version was published online in June 2006 with corrections to the Cover Date.     

CHEETAH virtual label switching router for dynamic provisioning in IP optical networks

Enabling new IP-based services such as triple and quad-play, as well as eScience applications at predetermined quality of service (QoS) measures, require the provisioning of guaranteed bandwidth pipes at varying granularities (e.g. from few Mbps to several Gbps and above). Dynamic provisioning of bandwidth pipes, whereby a connection is dynamically setup and released upon signalling, is a cost-effective method of enabling such services. Dynamic provisioning is a new paradigm in network control and management (NC&M) that requires the introduction of control plane (i.e. routing and signaling) capabilities within network elements such as routers, layer 2 switches and layer 1 cross-connects.In this paper we share our experience in the design and deployment of a Generalized Multiple Protocol Label Switching (GMPLS) control plane for layer 2 switches in the experimental Circuit-Switched High-Speed End-to-End Transport Architecture (CHEETAH). We call this software engine CHEETAH Virtual Label Switching Router (CVLSR). CVLSR allows non-GMPLS devices (e.g. Ethernet switches, routers and other cross-connects) to participate in the dynamic provisioning of end-to-end bandwidth-guaranteed connections. It extends the dynamic provisioning of connections to the end-users across different administrative domains. We have successfully deployed the CVLSR in CHEETAH optical network across HOPI/DRAGON network. The interoperability of the CVLSR with commercial GMPLS SONET-based cross-connect switches has been demonstrated.     

MPLS支持移动IP技术研究

移动IP是一种在全球Internet上为移动节点提供移动功能的方案。同时,鉴于MPLS是一种基于三层边缘路由、二层核心标签交换的技术,可以较大程度地提高分组的转发速度,业界对扩展MPLS功能使其支持移动性产生了极大的兴趣。文章主要讨论MPLS支持移动IP的技术细节。     

带内多波长光标记分组交换技术的研究

介绍了一种带内多波长光标记分组交换技术。在这种光交换中,光信头由若干个与光载荷处于同一通信信道内的具有不同波长值的光脉冲构成。探讨了包括信头产生和光分组形成部分的光发射机技术,包括数据恢复的接收机技术和包括路由处理的光交换节点技术。一个简化的实验演示了这种光交换的原理。     

Single modulator payload/label encoding and node operations for optical label switching

We present and analyze payload/label encoding based on a single Mach-Zehnder modulator, in which the payload is differential phase-shift keyed and the label is amplitude-shift keyed through modulation of either the modulator bias or the amplifier gain. The encoding is analyzed numerically and experimentally. Simultaneous encoding of a 10-Gb/s payload and a 155-Mb/s label is demonstrated with high receiver sensitivities. Penalty-free transmission over 80 km of standard single-mode fiber is achieved for both the payload (with dispersion compensation) and the label (without dispersion compensation). Furthermore, polarization-independent label processing and payload wavelength conversion at intermediate nodes are proposed for potentially cost-effective node operations.     

通用多协议标签交换技术研究

通用多协议标签交换技术(GMPLS)在光交换网中具有广阔的应用前景,但对它的研究还不够深入.首先指出GMPLS与传统的标签交换技术(MPLS)在7个方面的区别,然后刻画GMPLS光网络的一般结构,对特点进行了分析,指出光IP包交换的实质是光标记的转发与交换.设计了GMPLS光网络的技术方案,对关键技术进行分析,提出了一...     

A NEW SERVICE ARCHITECTURE OF FAST LABEL SWITCHING

Implementing QoS,one of the eternal research subjects,on Internet has been attracting a lot of attentions although several schemes are already available.This letter proposes a new service architecture-Scalable Tri-tier Service Architecture (STSA) and a fast label switching scheme,which can reduce the overhead of signaling and suit the applications of access demand for a great number of end users with QoS guarantee.Also presented in the letter is an implementation of STSA in MPLS scenario.     

Tree-type photonic switching networks

The enormous bandwidth offered by optical systems makes photonic switching a very attractive solution for broadband communications. Tree-type architectures play an important role in the design of photonic switching networks. The authors present and discuss all known tree-type space-division photonic switching networks architectures in a unified framework, and propose a number of new solutions. The discussed networks can be implemented with guided-wave-based switching elements, or laser diodes and passive splitters and combiners. The following network types are considered: conventional, simplified, and two-active stage networks. Techniques for improving SNR as well as waveguide crossover minimization are presented and discussed     

Reliable digital switching networks

A method for the design of economic and reliable PCM switching networks composed of uniform time-space elements is proposed. The described networks can be used in switching systems containing concentrators connected by an even number of PCM links to a main switching network.     

Single sided switching networks

A novel and simple architecture for realising single-sided, rearrangeably-nonblocking, N-port switching networks (N is a power of 2), that uses N/2 log (N/2) elements, together with an efficient routing algorithm with time complexity O(N log (N)) is presented. The networks also exhibit a useful measure of fault tolerance.<>     

Neural networks for switching

The author argues that a strong impetus for using neural networks is that they provide a framework for designing massively parallel machines. He notes that the highly interconnected architecture of switching networks suggests similarities to neural networks. He presents two switching applications in which neural networks can solve the problems efficiently. He shows that a computational advantage can be gained by using nonuniform time delays in the network     

Optically interconnected switching networks

Work on hybrid multistage switching networks is presented. A simple mapping rule is used to form a network using two-dimensional perfect shuffle interconnections, and other 2-D patterns are developed from other mappings. The general conditions for a 1-D net to be mappable into two dimensions are established, and it is pointed out that in practice all multistage interconnection networks (MINs) are mappable-a suitable mapping transformation is what is required. It is shown how to use the mapping process to produce hybrid MINs with a variable electronic island size. It is concluded that the design flexibility exists to take multistage processors and transform them into formats which are highly suitable for the employment of optical interconnects     

Multicast nonblocking switching networks

This paper considers three-stage switching networks for which nonblocking conditions with point-to-point traffic are given by the well known Clos (1953) theorem, under the assumption of absence of any optimized routing of the connections inside the network. We give the conditions for such a network to be strict-sense nonblocking under multicast traffic, by showing also that previously published papers, although claiming the same result, only provided sufficient conditions.