Study of Queueing Behaviour in IP Buffers

It is unquestioned that the importance of IP network will further increase and that it will serve as a platform for more and more services, requiring different types and degrees of service quality. Modern architectures and protocols are being standardized, which aims at guaranteeing the quality of service delivered to users. In this paper, we investigate the queueing behaviour found in IP output buffers. This queueing increases because multiple streams of packets with different length are being multiplexed together. We develop balance equations for the state of the system, from which we derive packet loss and delay results. To analyze these types of behaviour, we study the discrete-time version of the “classical” queue model M/M/1/k called Geo/Gx/1/k, where Gx denotes a different packet length distribution defined on a range between a minimum and maximum value

IP and ATM integration: A New paradigm in multi-service internetworking

ATM is a widespread technology adopted by many to support advanced data communication, in particular efficient Internet services provision. The expected challenges of multimedia communication together with the increasing massive utilization of IP-based applications urgently require redesign of networking solutions in terms of both new functionalities and enhanced performance. However, the networking context is affected by so many changes, and to some extent chaotic growth, that any approach based on a structured and complex top-down architecture is unlikely to be applicable. Instead, an approach based on finding out the best match between realistic service requirements and the pragmatic, intelligent use of technical opportunities made available by the product market seems more appropriate. By following this approach, innovations and improvements can be introduced at different times, not necessarily complying with each other according to a coherent overall design. With the aim of pursuing feasible innovations in the different networking aspects, we look at both IP and ATM internetworking in order to investigating a few of the most crucial topics/ issues related to the IP and ATM integration perspective. This research would also address various means of internetworking the Internet Protocol (IP) and Asynchronous Transfer Mode (ATM) with an objective of identifying the best possible means of delivering Quality of Service (QoS) requirements for multi-service applications, exploiting the meritorious features that IP and ATM have to offer. Although IP and ATM often have been viewed as competitors, their complementary strengths and limitations from a natural alliance that combines the best aspects of both the technologies. For instance, one limitation of ATM networks has been the relatively large gap between the speed of the network paths and the control operations needed to configure those data paths to meet changing user needs. IP\u27s greatest strength, on the other hand, is the inherent flexibility and its capacity to adapt rapidly to changing conditions. These complementary strengths and limitations make it natural to combine IP with ATM to obtain the best that each has to offer. Over time many models and architectures have evolved for IP/ATM internetworking and they have impacted the fundamental thinking in internetworking IP and ATM. These technologies, architectures, models and implementations will be reviewed in greater detail in addressing possible issues in integrating these architectures s in a multi-service, enterprise network. The objective being to make recommendations as to the best means of interworking the two in exploiting the salient features of one another to provide a faster, reliable, scalable, robust, QoS aware network in the most economical manner. How IP will be carried over ATM when a commercial worldwide ATM network is deployed is not addressed and the details of such a network still remain in a state of flux to specify anything concrete. Our research findings culminated with a strong recommendation that the best model to adopt, in light of the impending integrated service requirements of future multi-service environments, is an ATM core with IP at the edges to realize the best of both technologies in delivering QoS guarantees in a seamless manner to any node in the enterprise

WIRELESS APPLICATION PROTOCOL PERFORMANCE

Our work addresses the various performance testing aspects of the WAP architecture. For a systematic approach at first the architectural elements have to be identified. Then appropriate testing methods have to be found for testing each element and for the test of the entire architecture. In this paper we shall outline a theoretical basis for testing the influence on the performance of the wireless network and the IP backbone through the service quality parameters. First the service quality parameters are introduced from the provider and the user viewpoint, then the effect of the network (wireless and IP backbone) through bearers and transport protocol overheads on these parameters is analyzed. Conclusions are drawn regarding the results of the analysis and further steps are outlined for the refinement of our study. The results have not been confirmed by measurements yet, we are working on appropriate test scenarios to validate the outcomes and to refine our model. The final purpose of the work is to specify a performance parameter monitoring system for in-use WAP architectures that would tune the WAP parameters `on the fly´ in order to optimise the service quality parameters from the user viewpoint

Space Disaggregated Network Architectures

Modular, Open, Network Architectures (MONA) hold the promise of revolutionizing space system design, integration, test, operations, and overall business practices. Primarily focused on intra-spacecraft networking, MONA approaches also have the potential of providing highly enabling inter-spacecraft networking capability for system of system (SoS) space architectures, which include homogeneous constellations, heterogeneous satellite collections, and ground command, control and payload service platforms. This networked SoS approach is especially relevant in the context of disaggregated space systems, which are hoped to reduce total ownership cost and enhance resiliency of the space enterprise. Any MONA approach utilized for disaggregated space systems will need to have appropriate capabilities, including but not limited to scalability, versatility, fault tolerance, enabling quality of service guarantees, and security. Potential architectural approaches will include existing terrestrial standards, protocols, and software communication and management services. For instance, IP-based networking at first appears to be a reasonably good approach for space-space networks. At a conceptual level, it seems simple: just use the IP hardware, protocols, and software to communicate--among components within a spacecraft, between spacecraft, and between space and ground. Almost transparently, this simple view would suggest, IP in space opens a vast realm of services for space applications. However, given the many constraints that apply to space applications, it\u27s not as simple as it seems. In this context, various approaches to creating an efficient MONA approach for disaggregated space systems will be presented. Opportunities and challenges of such an approach will be discussed

WiLiTV: A Low-Cost Wireless Framework for Live TV Services

With the evolution of HDTV and Ultra HDTV, the bandwidth requirement for IP-based TV content is rapidly increasing. Consumers demand uninterrupted service with a high Quality of Experience (QoE). Service providers are constantly trying to differentiate themselves by innovating new ways of distributing content more efficiently with lower cost and higher penetration. In this work, we propose a cost-efficient wireless framework (WiLiTV) for delivering live TV services, consisting of a mix of wireless access technologies (e.g. Satellite, WiFi and LTE overlay links). In the proposed architecture, live TV content is injected into the network at a few residential locations using satellite dishes. The content is then further distributed to other homes using a house-to-house WiFi network or via an overlay LTE network. Our problem is to construct an optimal TV distribution network with the minimum number of satellite injection points, while preserving the highest QoE, for different neighborhood densities. We evaluate the framework using realistic time-varying demand patterns and a diverse set of home location data. Our study demonstrates that the architecture requires 75 - 90% fewer satellite injection points, compared to traditional architectures. Furthermore, we show that most cost savings can be obtained using simple and practical relay routing solutions

Calypso Service Architecture for Broadband Networks

The Calypso project aims at developing an extremely flexible control and service architecture for ATM-based broadband networks. This architecture provides various alternatives to distribute the network and service control functions among clients, servers and different network nodes. This means that a control or service function can reside not only in a network node, but in the customer's workstation or in the service provider's dedicated server. Instead of the traditional ATM or IN signalling, the Calypso architecture uses the TCP/IP protocol suite for the management and control of the network and services. The management, control and user data is transferred by means of IP switching. In addition to IP switching, the architecture will support endto -end native ATM streams with guaranteed Quality of Service. In this paper we compare the Calypso architecture with the traditional B-ISDN and IN architectures. We focus on describing the Java-based Service Execution Environment that provides..

Computing infrastructure issues in distributed communications systems : a survey of operating system transport system architectures

The performance of distributed applications (such as file transfer, remote login, tele-conferencing, full-motion video, and scientific visualization) is influenced by several factors that interact in complex ways. In particular, application performance is significantly affected both by communication infrastructure factors and computing infrastructure factors. Several communication infrastructure factors include channel speed, bit-error rate, and congestion at intermediate switching nodes. Computing infrastructure factors include (among other things) both protocol processing activities (such as connection management, flow control, error detection, and retransmission) and general operating system factors (such as memory latency, CPU speed, interrupt and context switching overhead, process architecture, and message buffering). Due to a several orders of magnitude increase in network channel speed and an increase in application diversity, performance bottlenecks are shifting from the network factors to the transport system factors.This paper defines an abstraction called an "Operating System Transport System Architecture" (OSTSA) that is used to classify the major components and services in the computing infrastructure. End-to-end network protocols such as TCP, TP4, VMTP, XTP, and Delta-t typically run on general-purpose computers, where they utilize various operating system resources such as processors, virtual memory, and network controllers. The OSTSA provides services that integrate these resources to support distributed applications running on local and wide area networks.A taxonomy is presented to evaluate OSTSAs in terms of their support for protocol processing activities. We use this taxonomy to compare and contrast five general-purpose commercial and experimental operating systems including System V UNIX, BSD UNIX, the x-kernel, Choices, and Xinu

Admission control in Flow-Aware Networking (FAN) architectures under GridFTP traffic

This is the author’s version of a work that was accepted for publication in Optical Switching and Networking. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Optical Switching and Networking, 6, 9 (2009) DOI: 10.1016/j.osn.2008.05.003Selected papers from First International Symposium on Advanced Networks and Telecommunication Systems, ANTS 2007Computing and networking resources virtualization is the main objective of Grid services. Such a concept is already used in the context of Web-services on the Internet. In the next few years, a large number of applications belonging to various domains (biotechnology, banking, finance, car and aircraft manufacturing, nuclear energy etc.) will also benefit from Grid services. Admission control is a key functionality for Quality of Service (QoS) provision in IP networks, and more specifically for Grid services provision. Service differentiation (DS) is a widely deployed technique on the Internet. It operates at the packet level on a best-effort mode. Flow-Aware Networking (FAN) that operates at the scale of the IP flows relies on implicit flow differentiation through priority fair queuing (PFQ). It may be seen as an alternative to DS. A Grid session may be seen as a succession of parallel TCP/IP flows characterized by data transfers with much larger volume than usual TCP/IP flows. In this paper, we propose an extension of FAN for the Grid environment called Grid over FAN (GoFAN). We compare, by means of computer simulations, the efficiency of Grid over DS (GoDS) and GoFAN. Two variants of GoFAN architectures based on different fair queuing algorithms are considered. As a first step, we provide two short surveys on QoS for Grid environment and on QoS in IP networks respectively