A new framework for GLIF Interdomain Resource Reservation Architecture (GIRRA)

Many existing and emerging Scientific high-end applications (E-science) require end-to-end circuits interconnecting Grid resources for large data transfers. A few advanced networks, mainly National Research and Education Networks (NRENs), such as Surfnet, National Lambda Rail and Internet 2, now provide mechanisms for end-users to reserve and provision lightpaths via middleware referred to as Network Resource Mangers (NRMs). Although, some progress has been made in automated intra-domain lightpath services, inter-domain lightpath provisioning still requires manual intervention and presents several key challenges such as scalability of topology information exchanged, consistency and scalability of information model, security of access to the resources, hybrid networking and multi-layer lightpaths, and accounting and billing. In this paper, we describe a new architectural framework called Global Lambda Integrated Facility (GLIF) Interdomain Resource Reservation Architecture (GIRRA) with the goal to provide an integrated response to these challenges. We propose a new approach to model GLIF network domains and GOLEs as virtual switches and to describe their behavior, functionality, policy capabilities, and topology aggregation. We define an inter-domain path computation model to determine paths that meet constraints and access policy restrictions. We propose a security framework for authentication and authorization of users and a model for accounting and billing that aims to provide easy and secure access to the resources. Key aspects of the GIRRA solution are that it focuses on the inter-dependence between different challenges of inter-domain path provision, and it is built around already existing solutions for intra-domain resource provisioning.     

A Cross-Layer Analysis of Session Setup Delay in IP Multimedia Subsystem (IMS) With EV-DO Wireless Transmission

This paper analyzes the session setup delay in the IP multimedia subsystem (IMS) with the CDMA2000 evolution data only rev. A (EV-DO rev. A) standard for wireless transmission. Session setup delay is particularly critical for interactive multimedia applications, such as gaming, push-to-X and voice over IP (VoIP), as it directly translates in user perception of service quality. Keeping signaling delay low, however, is a challenge in IMS due to the text-based nature of the session initiation protocol (SIP) for signaling, and, more significantly, due to the lossy and capacity constrained wireless links. To address this challenge, we analyze the session setup delay end-to-end, by taking into account key system properties across all layers, ranging from radio links to IMS signaling architecture. We present a model for cross-layer performance analysis and simulation, which includes the statistical properties of the EV-DO (rev. A) wireless channel, and also takes into consideration the properties of transport protocols (TCP, UDP) and SIP signaling (message size and compression). By means of analysis and simulations, we study the setup delay performance of a generic, multi-operator IMS communication scenario between two mobile users. We describe how session setup delay can be estimated and reduced in realistic IMS settings and we propose architecture alternatives to the basic IMS scenario. The results derived from this study show that the proposed methods can incrementally lead to a lower setup delay and less sensitivity to the radio transmission quality and frame error rate compared to the base IMS scenario     

Service-specific resource allocation in WDM networks with quality constraints

The need to establish wavelength-routed connections in a service-differentiated fashion is becoming increasingly important due to a variety of candidate client networks (e.g., IP, SDH, ATM) and the requirements for QoS-delivery within transport layers. The multiservice operation changes the way we deal with wavelength-routed paths, as they are now being characterized by manifold properties, such as transmission quality, restoration, network management, and policies. We propose a generic approach to service-differentiated connection accommodation in wavelength-routed networks where, for the network state representation, the supplementary network graphs are defined and referred to as service-specific wavelength-resource graphs. These graphs are used for the appropriate allocation of wavelengths on concatenated physical resources building a wavelength route, along which the necessary transmission quality is achieved and the required management and surveillance functions are provided. By considering twofold wavelength routing metrics, i.e., QoS metrics (service requirements) and resource metrics (quality constraints), these graphs can yield the solution to the QoS-routing problem, i.e., the provision of service-specific guarantees under quality constraints-a feature that is still missing from the existing architectures. The numerical analysis of dynamically reconfigurable multiservice WDM networks is presented for regular network operation as well as for optical network service restoration.     

Extending end-to-end optical service provisioning and restoration in carrier networks: opportunities, issues, and challenges

In this article, we address the opportunities, issues and challenges associated with end-to-end optical service provisioning and restoration in carrier networks. A number of scenarios are analyzed from a practical perspective, considering important aspects relevant to the management and control planes. Along the lines of three basic dimensions, to which we refer as locality, granularity, and ownership, we discuss the complexity associated with provisioning and restoring end-to-end optical services in regional (local scale) and national (global scale) networking scenarios. We identify a number of challenges in integrating a unified control plane solution and vendor-specific management and control planes with legacy carrier management systems.     

Path selection methods with multiple constraints in service-guaranteed WDM networks

We propose a new approach to constraint-based path selection for dynamic routing and wavelength allocation in optical networks based on WDM. Our approach considers service-specific path quality attributes, such as physical layer impairments, reliability, policy, and traffic conditions, and uses a flooding-based transfer of path information messages from source to destination to find multiple feasible paths. It is fully decentralized, as it uses local network state information. To better understand how multiple constraints impact the efficiency of wavelength routing, and consequently provision the service guarantees, we specifically focus on electronic regenerators that, while being widely considered as the basic building blocks for optical switching nodes, are likely to impose conflicting constraints on routing. For example, electronic regenerators extend the optical reach and could perform wavelength shifting, but also induce impairments, such as delays and operational costs. The question for constraint-based routing is how to account for these conflicting effects. To validate the network modeling, a wide range of networking scenarios are simulated, such as ring, mesh and interconnections of all-optical networks with electronic gateways. For all these scenarios, our approach is shown to efficiently accommodate multiple, conflicting routing metrics related to different services and network architectures.     

Editorial

Photonic Network Communications -     

模糊自整定PID及其在磨煤机控制中的应用

针对磨煤机非线性、大延迟和模型时变特性，提出了模糊自整定PID控制策略。结合MATLAB软件，用MATLAB语言编程，并与SIMULINK相结合实现了这种基于模糊规则的PID控制器的设计、分析与仿真。仿真结果表明，采用模糊自整定PID控制策略的磨煤机控制系统比采用常规PID控制具有更优越的性能。     

Architectural Requirements for Cloud Computing Systems: An Enterprise Cloud Approach

Cloud Computing is a model of service delivery and access where dynamically scalable and virtualized resources are provided as a service over the Internet. This model creates a new horizon of opportunity for enterprises. It introduces new operating and business models that allow customers to pay for the resources they effectively use, instead of making heavy upfront investments. The biggest challenge in Cloud Computing is the lack of a de facto standard or single architectural method, which can meet the requirements of an enterprise cloud approach. In this paper, we explore the architectural features of Cloud Computing and classify them according to the requirements of end-users, enterprises that use the cloud as a platform, and cloud providers themselves. We show that several architectural features will play a major role in the adoption of the Cloud Computing paradigm as a mainstream commodity in the enterprise world. This paper also provides key guidelines to software architects and Cloud Computing application developers for creating future architectures.     

How to buy a network: trading of resources in the physical layer

Recently, a number of new research initiatives, most notably UCLPv2 and GENI, have promoted the dynamic partition of physical network resources (infrastructure) as the means to operate the network, and to implement new protocols and services. This has led to a number of open issues such as resource discovery, implementation of resource partitioning, and the aggregation of resources to create arbitrary network topologies. To us, the key issue is the design of a mechanism to trade, acquire, and control network resources, given a choice of providers of physical resources (infrastructure providers). In this article we present an architecture that allows physical resources to be traded, while granting users controlled access to the acquired resources via a policy enforcement mechanism. In addition, it allows resource provider domains to be linked via configurable, provider-neutral resource exchange points that are the physical resource equivalents of the pooling point, or Internet exchange point (IXP). We demonstrate how our trading system will operate by presenting a use case in which a network topology is constructed using resources from multiple providers, be it Internet service providers (ISPs), or National Research Experimental Network (NREN) providers. The use case also shows how a dynamic reconfiguration can be effected by the customer though the use of simple access control policies, without involving the provider