A scaleable VP restoration system for reliable Internet configuration

BFRA: bounded flooding routing algorithm for provisioning the globally optimal route in a hierarchical ATM network

The future Internet will support a large variety of services whose QoS requirements may vary widely. In order to provide scalable quality of service traffic aggregation may be necessary. We examine several approaches to providing scalable QoS services which includes soft QoS with relative performance guarantees, and hard performance guarantees signaled by RSVP over an aggregated cell switched core. In these approaches QoS is based on aggregate traffic. The question then arises as to what level of QoS is perceived by individual flows within the aggregate. This has an important implication on QoS guarantees which the network can make to individual users. To provide answers to the above question we analyse per-flow and aggregate QoS in an ATM virtual path (VP) which is used as an example of a cut-through handling IP flows. Using cell loss as a measure of QoS, our analysis allows us to investigate the impact of the parameters of individual flows on per-flow QoS. We then compare per-flow QoS against the QoS experienced by the aggregate flow in the VP. Based on numerical tests we find that cell loss experienced by individual flows may be very different from cell loss experienced by the aggregate flow. Thus if aggregate cell loss is used as a QoS constraint in dimensioning of VP this may lead to unfair treatment of flows and hence to potential user dissatisfaction.

We study the survivability of a meshed-ring communication network that employs cross-connect switches. For WDM networks, the cross-connect switches are implemented as wavelength routers. Nodes can also provide cross-connection at the ATM VP (virtual path) level. By meshing the ring, the nodal degree of connectivity is increased as compared to a ring topology, and thus more alternative (protection) paths are available. For routing purposes, wavelength subnetworks are embedded in the topology. Nodes communicate with each other across one of the subnetworks to which both belong. We consider two types of subnetwork topologies to simplify the routing in a normal (nonfailure) situation. For each type of subnetwork, different protection methods are proposed to protect against a single link and/or nodal failure. The throughput performance of such meshed-ring networks under failure conditions is clearly superior to that achieved by (SONET) ring networks. We show that certain protection methods even result in lower values of the protection capacity as well as the protection capacity ratio (i.e., the overall capacity used under a failure divided by the total capacity) as compared to ring networks. We also present methods for constructing wavelength subnetworks to achieve single-failure protection using the minimal number of wavelengths.

Grid is a distributed infrastructure which allows large scale resources sharing and system integration. Task scheduling in grid becomes more complicated when strategy needs to combine user's QoS with system's computing performance. On the basis of analysing classic Min-min heuristic, an improved task scheduling algorithm using triangle module operator to integrate user's QoS with system's computing performance is proposed. Simulation are conducted on GridSim, and the results strongly demonstrate the proposed algorithm performs better on makespan, resource load balancing and user's QoS utility than BF-Min-min and Min-min which does not consider user's QoS requirements.

In an ATM network, a virtual path (VP) is a labeled path which can be used to transport a bundle of virtual connections (VCs) and to manage the resources used by these connections. The ATM multimedia leased line service is provided across user-to-user VPs. The customers can increase/decrease the VP bandwidth according to their demand. This paper proposes a method to derive the least required bandwidth on a VP which is the minimum amount of bandwidth estimated to satisfy the QoS requirement of the VCs. The least required bandwidth can be a warranty of the VP resource reallocation.

We introduce a meshed ring communications network which employs cross‐connect switches. The crossconnect switches can be implemented as wavelength routers resulting in WDM networks, or as ATM Virtual Path (VP) switches leading to ATM compatible network systems. We show in the paper that this network architecture results in a significant increase in throughput performance in comparison with (SDHISONET) ring networks. For a certain class of meshed rings, under a uniform traffic matrix, we derive the optimal topology which achieves maximum throughput efficiency. Using such a topology, we obtain upper and lower bounds on the number of wavelengths required to achieve that efficiency level. The network is divided into (overlapping) communities of nodes. Each community is assigned a wavelength and a subnetwork (identified as a wavelength graph). Each pair of nodes in a community can communicate across the associated wavelength graph. Wavelength graphs (subnets) are constructed to demonstrate the implementation of the routing scheme using the number of wavelengths that is equal to the derived upper bound. For practical implementation reasons, we investigate the performance of networks which employ a reduced number of wavelengths. We show that by modifying the topological layout of the meshed ring network, we can reduce substantially the number of required wavelengths, while incurring just a modest reduction in throughput efficiency.

The transmission of ATM cells through a virtual path (VP) which comprises one or more virtual channel (VCs) multiplexed through a VP is examined. Constant bit rate (CBR) sources are used. During the process, there are ATM cell loss, cell delay, and the performance degradation. This paper proposes the techniques of CDMA, OOCs code and 2/sup n/ prime code for improve the performance and to compare two codes when using an ATM network. The results show that when using the same code length a 2/sup n/ prime sequence code has a greater performance than OOCs code.

Relay selection is a challenging issue in cooperative communication networks. In particular, in a multi-user multi- concurrent-transmission network, effects of the resource sharing of a relay by its served users on the relay selection strategy need to be taken into account. There is little research on this investigation in literature. In this paper, we propose a novel efficient and fair relay selection strategy, in which individual user's QoS requirement is inherently taken into account. In terms of efficiency, the proposed strategy is of low computational complexity. In terms of fairness, the system resource is utilized fairly among all relaying nodes so that the system has the best potential to accommodate as many users as possible. Simulation results indicate that the proposed selection strategy outperforms many existing ones, therefore justifying our arguments.

Discovery of suitable Web services for a given user requirement is one of the key technology. A mechanism is proposed to support QoS-based semantic web service discovery in the paper. Firstly, to reduce the overhead and enhance the discovery efficiency, genetic algorithm is adopted as a method of service clustering. Furthermore, based on user's QoS requirements, the QoS-based service matchmaker was realized. In the end, simulation results demonstrated the effectiveness of the proposed method.

With the development of 5G new services, the IP network layer needs to provide the service layer with deterministic carrying and forwarding capabilities characterized by differentiation and quality assurance. To effectively manage and utilize differentiated forwarding resources at the IP network layer, an open framework for IP network differentiated services based on SRv6 is proposed. The framework combines SRv6 BSID to abstract the end-to-end network forwarding path. A unified service resource pool with differentiated characteristics has been formed, and the service layer can schedule differentiated services on demand. We set up a typical operator backbone network environment in the laboratory, and verified that switching differentiated service resources on demand can make the video services own a better forwarding path. This framework can reduce the coupling between the service layer and the network layer, and provides differentiated services with guaranteed network quality through overlay and underlay collaboration.

Traffic engineering in IP/WDM networks can be pursued in two fashions: overlay and integrated. With overlay traffic engineering, operations in one layer can be independent from those in the other layer. Traffic engineering solutions developed for either IP networks or WDM networks can be directly applied to each layer, respectively. At the present stage, an anticipated first step towards IP over WDM is to hook up IP router interfaces to optical add/drop multiplexer client add/drop ports. This forms an overlay network in which WDM serves as the server layer and IP behaves like the client layer. This overlay client-server network is a natural match to the notion of overlay traffic engineering. With integrated traffic engineering, optimization with respect to selected objectives is pursued coordinately across both the IP and WDM layers. It is made possible by mechanisms such as multi-protocol lambda switching that allows a unified control plane across both layers. With the emergence of more sophisticated hardware that integrates functionality of both IP and WDM at each network element, integrated traffic engineering can be performed more naturally and efficiently.

With networks increasingly moving into virtually every aspect of our daily life, security is gaining importance, not only from the traditional perspective of communication but the network's growing role in modern automation and control. The traditional, certification based approach attempts to guarantee the security of a network through certification. Certified networks are generally confined to a limited domain and, as a result, they are isolated, costly, and under-utilized. In contrast, this paper presents a new principle – user-level, security-on-demand system, wherein the network allocates, where possible, the security resources commensurate with the user's request for transporting message(s) through the network securely. This principle is successfully demonstrated for the current Asynchronous Transfer Mode (ATM) networks, and is the result of an integration of the fundamental framework for network security, recently proposed by the authors in the literature, with the unique characteristics of ATM networks. The framework encapsulates the fundamental knowledge and set of relationships in network security and permits scientific and systematic reasoning about network security. It also enables all user groups – military, government, industry, and academia, to define their security requirements in a uniform manner. The security-on-demand approach promises the development of a "mixed use" class of networks in the future that may be simultaneously shared by different groups of users, with the system sustaining the diverse security requirements of each user. A unique characteristic in ATM network design is the dynamic call setup process. Under it, a network first establishes a virtual path or route for a user's call, guided by the user's requirements, and then transports the messages when a route has been successfully determined. This unique ATM characteristic is integrated with the framework to yield a successful demonstration of the proposed, user-level, security-on-demand approach. Utilizing the security framework as the foundation, every element of the network – node and link, is characterized by a security matrix that reflects its security resources. Every user is permitted to specify the security requirement for the call through a matrix, which expresses the limits of the security resources that the traffic cells must encounter during their transport through the network. Thus, during the dynamic establishment of the virtual path, every node and link is examined to ensure that the user-specified security is met, in addition to bandwidth and other Quality of Service (QoS) requirements. Traffic is launched when the call setup succeeds, otherwise, the call fails. Like all networks, the ATM network inherently consists of geographically dispersed entities and, as a result, the resource allocation strategy is necessarily distributed. Furthermore, as the network operation progresses, the resource availability scene changes dynamically. This paper proposes a unique function that reduces the key network resource parameters at a node to a single value, termed Node Status Indicator (NSI). The NSI value is computed dynamically at every node and disseminated across the network to be utilized by a node to refine its determination of a virtual path for a user call. The aim of the NSI is to improve the resource utilization in the network. The proposed approach is modeled for a large-scale, representative, 40-node ATM network. Utilizing stochastic input traffic that is synthesized to reflect realistic operating conditions, the model is simulated extensively on a testbed of 35+ Pentium workstations, under Linux, configured as a loosely-coupled parallel processor, utilizing an accurate, asynchronous, distributed simulator. The simulator implements the key characteristics of the ATM Forum proposed P-NNI 1.0 and UNI 3.0 standards. While the simulation results reflect a successful realization of the proposed approach, analysis reveals minimal impact of incorporating security on ATM network performance, as measured through call success rates and call setup times. In contrast, the tradition has been to incorporate security into large-scale systems and networks as an afterthought, i.e. adding hardware and software devices after the design has been completed, resulting in performance degradation. Also, while the use of NSI is observed to yield slightly lower average call setup rates and slightly higher average call setup times, a careful analysis of the trace of the calls as they progress through the system, reveals that, in general, calls are dispersed throughout the network, seeking to utilize all available resources of the network more evenly.

The cyber-physical system is highly desirable for real-time perception and dynamic control, especially in task scheduling and network communication for large and complex engineering systems. In most of the applications, the resource scheduling of cyber and physical network are independent on each other, which may cause severe deterioration of the network performance. To implement the cognitive cooperation between the upper layer of industrial services and the underlying network, we propose a cooptimization method in this article. We adopt the software defined networking technology to extract the network control logic, which is integrated with the upper-level task scheduling. This cooptimization scheme can dynamically calculate optimal end-to-end virtual paths over the underlying network infrastructures. Meanwhile, it can also adjust the task scheduling of the upper-level network by signals derived from the underlying network. Simulation results show that our proposed scheme outperforms the traditional method in terms of task acceptance rate, average end-to-end delay, and network load balance degree.

An ATM bandwidth management algorithm coupled with multilevel survivability constraints based on virtual paths (VP) is proposed. Two key features in regard to survivable ATM networks are incorporated in the new algorithm: (1) Preserve the integrity of each flow, and (2) Utilization of the excess spare bandwidth in the network to route working traffic when the network is overloaded. The algorithm is an integer optimization problem and is solved using Lagrangian relaxation with subgradient optimization. Results obtained from a sample network are shown.

Most studies of resource allocation mechanisms have used a performance model of the resource, where the very concept of the resource is defined in terms of measurable qualities of the service such as utilization, throughput, response time (delay) and so on. Optimization of resource allocation is defined in terms of these measurable qualities. One novelty introduced by the economic approach is to design a system which takes into account the diverse QoS requirements of users, and therefore use multiobjective (utilities)optimization techniques to characterize and compute optimum allocations. Economic modelling of computer and communication resource sharing uses a uniform paradigm described by two level modelling: QoS requirements as inputs into a performance model that is subject to economic optimization. In a first step, one transforms QoS requirements of users to a performance (example: queueing service model).This model establishes quantifiable parameterization of resource allocation. For example, average delay QoS requirement, when based on a FIFO queueing model, is a function of resources, bandwidth and buffer, and user traffic demands. These parameters are then used to establish an economic optimization model. The question of whether the resource is a piece of hardware, a network link, a software resource such as a database or a server, or a virtual network entity such as a TCP connection is not of primary importance. The first modeling transformation eliminates the details and captures the relevant behaviors and the optimization parameters. We consider a decentralized model of network and server economies , where we show efficient QoS provisioning and Pareto allocation of resources (network and server resources) among agents and suppliers, which are either network routes or servers (content providers)