David Chieng

Evaluation of IPv6 and comparative study with different operating systems

With the increasing popularity in recent years, many popular operating system (OS) venders worldwide have incorporated Internet protocol version6 (IPv6) into their OS. The performance of the IP stack, together with the behavior of the OS greatly affects the efficiency of network applications built on top of it. Like any other protocols, the acceptance of various IPv6 implementations heavily relies on the end-user performance. Hence with the availability of a variety of IPv6 implementations, it is essential to evaluate their performance under different operating systems. An investigation of IPv6 stack performance on three different operating systems namely, Windows2003, Redhat Linux 9.0 (Redhat9.0) and FreeBSD4.9 is discussed in this paper. Performance analysis and comparison of the three IPv6 stacks, some interesting points raised by the experimental results are addressed.

A Mobile Agent Brokering Environment for the Future Open Network Marketplace

The growth of commercial activities across networks has led to the network itself becoming a competitive marketplace with a multitude of vendors, operators and customers. In such an environment, users will’ shop around’ for the best deals in terms of network financial costs and services. Intelligent, autonomous and mobile software agents introduce an alternative approach that facilitates expertise-brokering activities on behalf of the users. In this paper we present such an agent supported brokering scenario. The scenario involves interactions between Java-based mobile agents and an interactive model of the network. The paper describes how this prototyping environment can be used to examine the impact of mobile agents for brokering network resources in the future open network marketplace.

Agent-Enhanced Dynamic Service Level Agreement in Future Network Environments

Current network infrastructures are experiencing rapid transformation from providing mere connectivity, to a wider range of flexible network services with Quality of Service (QoS). We propose an agent-enhanced system that facilitates dynamic Service Level Agreement (SLA) activities, such as end-to-end QoS specifications and service price negotiations in such an environment. A prototype system consisting of real-time Java-based agents that interacts with a simulated network was developed to demonstrate scenarios and enable analysis. The studies show that this form of dynamic SLA negotiation introduces many innovative ways on how network services can be provisioned. This paper also highlights the effects of implementing dynamic connection bandwidth pricing on traffic load and network providers revenues.

Supporting carrier grade services over wireless mesh networks: The approach of the European FP-7 STREP CARMEN [Very Large Projects]

CARMEN is a three-year Specific Targeted Research Project (STREP) funded by the European Commission within the 7th Framework Program. The CARMEN access network will complement existing access technologies by exploiting low cost mesh networking techniques, thus minimizing deployment and maintenance costs. The CARMEN architecture introduces an abstraction layer that hides the specifics of the underlying access technology providing an abstract interface on top of which higher layers can be easily developed. This allows for the integration of current and future heterogeneous wireless technologies to provide scalable and efficient mobile ubiquitous Internet access, able to adapt to different environments and user requirements. Following these goals, CARMEN aims to define, study and implement link and technology abstractions, mobility support, and quality of service. The architecture also includes advanced monitoring features that allow for dynamic self-configuration, thereby reducing the installation and operational costs.

SLA brokering and bandwidth reservation negotiation schemes for QoS-aware internet

We present a novel Service Level Agreement (SLA)-driven service provisioning architecture, which enables dynamic and flexible bandwidth reservation schemes on a per-user or per-application basis. Various session level SLA negotiation schemes involving bandwidth allocation, service start time and service duration parameters are introduced and analyzed. The results show that these negotiation schemes can be utilized for the benefit of both end users and network providers in achieving the highest individual SLA optimization in terms of key Quality of Service (QoS) metrics and price. The inherent characteristics of software agents such as autonomy, adaptability and social abilities offer many advantages in this dynamic, complex, and distributed network environment especially when performing Service Level Agreements (SLA) definition negotiations and brokering tasks. This article also presents a service broker prototype based on Fujitsus Phoenix Open Agent Mediator (OAM) agent technology, which was used to demonstrate a range of SLA brokering scenarios.

Extremely dense wireless networks [Guest Editorial]

The ever growing demand from mobile network users is pushing the current wireless technologies toward their limits. As a matter of fact, not even the most optimistic promises from emerging standards, such as LTEAdvanced and IEEE 802.11ac/ad/af, will be able to satiate the huge appetite for bandwidth of the future users of 5G networks — at least, unless the size of cells is reduced dramatically. This situation will soon create a desperate need for extremely dense wireless networks (DenseNets).

POWARED for Non-Linear Adaptive RED

Random early detection (RED) is widely deployed as a congestion control mechanism in the routers. However, RED is often limited by the difficulty of tuning its parameters under different congestion levels. Adaptive RED (ARED) addresses this problem by adaptively adjusting the aggressiveness of RED settings to keep the average queue size between minimum threshold (minth) and maximum threshold (maxth ). We have observed that the additive increase multiplicative decrease (AIMD) approach used in ARED can always maintain high link utilization but not effective enough in preventing high packet loss rates under heavy congestion. In this paper, we propose an adaptive version of RED which applies non-linear power function instead of linear AIMD approach to achieve better link utilization as well as minimizing the packet loss rates under various traffic load conditions

An Architecture for Agent-Enhanced Network Service Provisioning through SLA Negotiation

This paper focuses on two main areas. We first investigate various aspects of subscription and session Service Level Agreement (SLA) issues such as negotiating and setting up network services with Quality of Service (QoS) and pricing preferences. We then introduce an agent-enhanced service architecture that facilitates these services. A prototype system consisting of real-time agents that represent various network stakeholders was developed. A novel approach is presented where the agent system is allowed to communicate with a simulated network. This allows functional and dynamic behaviour of the network to be investigated under various agent-supported scenarios. This paper also highlights the effects of SLA negotiation and dynamic pricing in a competitive multi-operator networks environment.

SLA-driven flexible bandwidth reservation negotiation schemes for QoS aware IP networks

We present a generic Service Level Agreement (SLA)-driven service provisioning architecture, which enables dynamic and flexible bandwidth reservation schemes on a per- user or a per-application basis. Various session level SLA negotiation schemes involving bandwidth allocation, service start time and service duration parameters are introduced and analysed. The results show that these negotiation schemes can be utilised for the benefits of both end user and network provide such as getting the highest individual SLA optimisation in terms of Quality of Service (QoS) and price. A prototype based on an industrial agent platform has also been built to demonstrate the negotiation scenario and this is presented and discussed.

A policy-based bandwidth resource provisioning architecture

We present a policy-based, agent-enhanced resource provisioning architecture, which facilitates flexible and quantitative end-to-end bandwidth reservation and management on a per-user, per-application or per-flow basis. Based on this architecture, various session level Service Level Agreement (SLA) negotiation schemes involving bandwidth allocation, service start time, guaranteed session duration can be introduced. The results show how these negotiation schemes can be utilised for the benefits of both network users and providers.