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SLA-based dynamic resource management in wireless environments
Abstract
In this article, we focus on the service-driven management of quality of service and user access in wireless corporate networks. We propose a service-level agreement (SLA) oriented nomadism management architecture with a top-down vision starting by the specification of company objectives and going down to device-level configurations. We define an algorithm for the automatic translation of application-level quality assurance parameters into network-level configuration parameters. The description of the prototype implementation of our solution to the SLA-driven enterprise nomadism management is given and preliminary results on the self-adaptive capabilities of our mapping algorithm are given.
... There are several research works that deal with QoS management, based on the application needs and user characteristics like those presented in [19], [20] and [21]. For example, a user profile for QoS negotiation has been defined when specifying a "smart" interface that allows users to negotiate QoS [19]. ...
Based on the IP technology, the next generation networks (NGN) must overcome the main drawbacks of this technology consisting in the lack of quality of service (QoS), security and mobility management. To ensure a service offer in an NGN environment, a protocol for negotiating a service level can be used. However, most of the existing negotiation protocols allow the establishment of a service level which includes only QoS. As for security and mobility, they were often not covered by these negotiations, and therefore managed independently. However, securing a service can cause degradation of the QoS, and the mobility of a user can change the service needs in terms of QoS and security. Thus, we need to simultaneously manage QoS and security while taking into account user's mobility. In this context, we propose an end-to-end NGN architecture with several autonomous domains, where each domain is under the authority of an autonomic domain manager. We provide those autonomic managers with a negotiation capability to achieve an agreement between the different domains involved in the transport of various offered services. This agreement may cover different aspects such as QoS, security and takes into account the user profile. The negotiation process will be based on SLNP (Service Level Negotiation Protocol) which uses Web Services technologies in order to enable interoperability between the managers of the different autonomous domains involved in the service transport.
The paper describes a nomadic guide that considers the context of use (CoU) for information selection and presentation. A
nomadic system is de- fined by continuous access to information spaces independent from specific de- vices. The CoU is defined
by the location and characteristics of the user. Inter- ests of the user deduced from the navigation in the physical and information
space are the main goal of information adaptation in the paper. A prototype of a nomadic system that adapts the information
to the user needs is presented.
In this work, we focus on Service Level Agreement "SLA" driven nomadism management in wireless corporate networks. We adopt a novel top down approach in dealing with this problem. We aim at automatic equipment configuration based on high level company objectives and strategies for nomadism. For that, we propose a service-oriented management architecture, which starts at the specification of company objectives and strategies and down through SLAs until reaching instance level configurations.
In this paper, we present several challenges and innovative approaches to support nomadic computing. The nomadic computing environment is characterized by mobile users that may be connected to the network via wired or wireless means, many of whom will maintain only intermittent connectivity with the network. Furthermore, those accessing the network via wireless links will contend with limitations of the wireless media. We consider three general techniques for addressing these challenges: (1) asymmetric design of applications and protocols, (2) the use of network-based proxies which perform complex functions on behalf of mobile users, and (3) the use of pre-fetching and caching of critical data. We examine how these techniques have been applied to several systems, and present results in an attempt to quantify their relative effectiveness.
With the evolution of the QoS-capable third generation wireless networks, the wireless community has been increasingly looking for a framework that can provide an effective, network independent, end-to-end QoS control. In this paper, we first construct such a framework and then describe how dynamic SLA-based control can be used to achieve end-to-end QoS in a wired and wireless (UMTS) environment. The proposed framework, which is an extension of the IST CADENUS project, offers an effective wired-wireless QoS translation, an efficient QoS control and management, and a dynamic SLA policy-based QoS provisioning.
Middleware systems have emerged to support applications in
heterogeneous and ubiquitous computing environments. Specifically,
future middleware platforms are expected to provide quality of service
support, which is required by a new generation of QoS-sensitive
applications such as media streaming and e-commerce. This article
presents four key aspects of a QoS-aware middleware system: QoS
specification to allow description of application behavior and QoS
parameters; QoS translation and compilation to translate specified
application behavior into candidate application configurations for
different resource conditions; QoS setup to appropriately select and
instantiate a particular configuration; and finally, QoS adaptation to
adapt to runtime resource fluctuations. We also provide a comparison of
existing QoS-aware middleware systems in these four aspects
In multimedia systems, session coordination technique is important to accommodate a new session and re-distribute reclaimed resources when tough continuous media session is exiting. Although end-users do not want to specify the quality of service (QOS) in an exact memory size like in KB or KB/s of bandwidth, such rigid usages are necessary for admission control and coordination. Therefore, we introduce the multi-level quality specification and QOS translation mechanism to put it into the quantitative expression which the system can handle. Nonetheless, session coordination have demanded complicated computation or presented an NP-complete problem. Constraining QOS specification, we invent a simplified session coordination method which is feasible enough to actually implement. This paper reports experiments on QOS translation and multiple session coordination using the Conductor/Performer system on top of Real-Time Mach 3.0.
In this work we propose GXLA, a language for the specification of Service Level Agreements (SLA). GXLA represents the implementation of the Generalized Service Level Agreement (GSLA) information model we proposed in a previous work. It supports multi-party service relationships through a role-based mechanism. It is intended to catch up the complex nature of service interactivity in the broader range of SLA modeling of all sorts of IT business relationships. GXLA is defined as an XML schema which provides a common ground between the entities in order to automate the configuration. GXLA can be used by service providers, service customers, and third parties in order to configure their respective IT systems. Each party can use its own independent SLA interpretation and deployment technique to enforce the role it has to play in the contract. An illustrative VoIP service negotiation shows how GXLA is used for automating the process of SLA negotiation and deployment.
The Differentiated Services (DiffServ) architecture is receiving wide attention as a framework for providing different levels
of service according to a Service Level Agreement (SLA) profile. The edge routers in a DiffServ network mark/shape/police
flows based on their SLAs, and the core routers offer packets different treatments using the marks they carry. Core routers
handle aggregates of flows instead of individual flows, which is known to considerably reduce the complexity of DiffServ.
Tuning core routers is clearly an important issue to satisfy the needs of traffic marked at the edges. This tuning is actually
characterized by extensive manual work, based on a trial-and-error process, which is often ineffective, time-consuming and
costly to network managers. In this paper, we propose a dynamic, self-tuning mechanism for allocating resources in core routers
among Diffserv services. Our mechanism is easy to implement, and does not require any particular signaling. It ensures that
SLAs are respected, and allows at the same time an efficient utilization of network resources. We validate the performance
of our mechanism by a campaign of experiments on a real network testbed.
In order to improve the scalability of the IETF’s PBM architecture, we previously proposed an extension to this architecture.
The aim of our proposal was to facilitate the support of on-demand resource allocation in stateless IP networks. The proposed
schema distribute part of the decision making process but keeps centralized the bandwidth brokerage operation as this latter
uses a critical resources (traffic matrix). Our current work aims to render the PBM architecture completely distributed by
designing a scalable scheme for bandwidth brokerage. To that end, we propose using a proactive two-tier scheme in order to
improve the scalability of the resource management procedures. In this paper, we present the proposed scheme, its design features
and the set of experimentations we realized in order to demonstrate its performances.
During the past years, IP networks have grown considerably in size and complexity: the number and the variety of the connected devices have increased, new applications have emerged and Quality-of-Service is increasingly demanded. In such networks, traditional management techniques seem to suffer from significant scalability and efficiency limitations. Policy-Based Networking (PBN) has emerged as a promising paradigm for IP networks operation and management. In PBN, policy servers enforce network policies by sending the appropriate configuration data to the managed devices. IETF is currently developing COPS (Common Open Policy Service) and its extension for policy provisioning, COPS-PR, as the protocols to implement PBN. COPS-PR, although initially biased towards DiffServ, has received significant attention and seems efficient for several other management areas, such as accounting and IP filtering. However, in COPS-PR, the rigidity of the policy-enforcing mechanisms at the managed devices restricts the intelligence that can be pushed into them. This work attempts to raise these limitations by extending the COPS-PR protocol with meta-policies. Meta-policies are rules that can be stored and processed by the devices, independent of their semantics. They allow intelligence to be pushed towards the managed device, making in this way the scheme more efficient, scalable, distributed and robust.
We consider whether the off-line compilation of a set of Service Level Agreements (SLAs) into low-level management policies can lead to the runtime maximization of the overall business profit for a service provider. Using a simple Web application hosting SLA template for a utility service provider, we derive low-level QoS management policies and validate their consistency. We show how the default first come first served (FCFS) mechanism for the runtime scheduling of triggered policies fails to deliver an all times maximum business profit for the service provider. To achieve a better business profit, first a penalty/reward model that is derived from the SLA Service Level Objectives (SLOs) is used to assign runtime utility tags to triggered policies. Then three policy scheduling algorithms, which are based on the prediction of the future state of the running SLAs, are used to drive the runtime actions of the Policy Decision Point (PDP). The prediction function per see involved the unsolved problem of predicting in realtime the evolution of the transient state of a variant of an M/M/Ct/Ct queue. A simple approximative solution to the latter problem is provided. Finally, using the VS policy simulator tool, comparative simulation results for the business profit generated by each of the proposed policy scheduling algorithms are presented. VS is a novel tool which we have developed to respond to the increasing need of benchmarking SLA and policy-based management solutions.
There are a diverse range of products and services currently on
the market, but cellular or personal communications services (PCS) radio
networks probably have the highest public profile. These services
provide highly mobile, widely accessible two-way voice and data
communications links. In general, the most complex and expensive part of
the radio path for these systems is the base station. As a result,
manufacturers have been designing networks that have high efficiency in
terms of the bandwidth occupied and the number of users per base
station. Base station antenna arrays are a promising method for
providing large capacity increases in cellular mobile radio systems.
This article considers channel-modeling issues, receiver structures, and
algorithms, and looks at the potential capacity gains that can be
achieved. It considers antenna arrays for the mobile-to-base-station or
reverse link of a CDMA cellular system. It begins with an introduction
to CDMA communications systems and also addresses the general topic of
antenna array receivers
The management of network infrastructure in an enterprise is a
complex and. daunting affair. In an era of increasing technical
cornplexity, it is becoming difficult to find trained personnel who can
manage the new features introduced into the various servers, routers,
and switches. Policy-based network management provides a means by which
the administration process can be simplified and largely automated. In
this article we look at a general policy-based architecture that can be
used to simplify several new technologies emerging in the context of IP
networks. We explain how network administration can be simplified by
defining two levels of policies, a business level and a technology
level. We discuss how business-level policies are validated and
transformed into technology-level policies, and present some algorithms
that can be used to check for policy conflicts and unreachable policies.
We then show how to apply this architecture to two areas: managing
performance service level agreements, and supporting enterprise
extranets using IPSec communication
Wireless local-area networks (WLANs) based on the IEEE 802.11 technology have been widely adopted for private use over the past few years. However, several issues remain concerns for large-scale deployment in corporate environments. Enforcing security and quality-of-service (QoS) has become a fundamental challenge to managing IEEE 802.11-based enterprise networks. In order to provide corporate networks with a global management solution, we have designed a service-oriented management system that enables user-centric service provisioning, while enforcing security and QoS requirements. As enterprises may be comprised of a number of distinct networks, we have extended our system to support the roaming of users between different enterprise sites. In this paper, we describe the design, implementation, and performance evaluation of our solution.
An Expedited For-warding PHB, 1999. (a) Simulation result for the scenario of table 2 with averaging interval 5 seconds (b) Simulation result with averaging interval = 2 seconds
- V Jacobson
- K Nichols
- K Poduri
V. Jacobson, K. Nichols, K. Poduri, et al. An Expedited For-warding PHB, 1999. (a) Simulation result for the scenario of table 2 with averaging interval 5 seconds (b) Simulation result with averaging interval = 2 seconds. Figure 6. Impact of Policies on Network Behaviour
Advanced Routing and Traffic Control HOWTO, A very hands-on approach to iproute2, traffic shaping and a bit of netfilter
- B Hubert
- Linux
An Expedited Forwarding PHB