We present a novel approach to building and deploying network protocols. The approach is based on mobile code, demand loading, and caching techniques. The architecture of our system allows new protocols to be dynamically deployed at both routers and end systems, without the need forcoordination and without unwanted interaction between co-existing protocols. In this paper, we describe our architecture and its realization in a prototype implementation. To demonstrate how to exploit our architecture, we present two simple protocols that operate within our prototype to introduce multicast and mobility services into a network that initially lacks them. 1

Multicast services have been increasingly used in large scale continuous media applications. The quality-of-service (QoS) requirements of these continuous media applications prompt the necessity for QoS-driven, constraint-based multicast routing. This article provides a comprehensive overview of existing multicast routing algorithms, protocols, and their QoS extension. In particular, we classify multicast routing problems according to their optimization functions and performance constraints, present basic routing algorithms in each problem class, and discuss their strengths and weakness. We also categorize existing multicast routing protocols, outline the issues and challenges in providing QoS in multicast routing, and point out possible future research directions.

Active networks permit applications to inject programs into the nodes of local and, more importantly, wide area networks. This supports faster service innovation by making it easier to deploy new network services. In this paper, we discuss both the potential impact of active network services on applications and how such services can be built and deployed. We explore the impact by suggesting sample uses and arguing how such uses would improve application performance. We explore the design of active networks by presenting a novel architecture, ants, that adds extensibility at the network layer and allows for incremental deployment of active nodes within the Internet. In doing so, ants tackles the challenges of ensuring that the exibility o ered by active networks does not adversely impact performance orsecurity. Finally, we demonstrate how a new network service may be expressed in ants.

Abstract—This paper addresses the resource allocation problem for multiple media streaming over the Internet. First, we present an end-to-end transport architecture for multimedia streaming over the Internet. Second, we propose a new multimedia streaming TCP-friendly protocol (MSTFP), which combines forward estimation of network conditions with information feedback control to optimally track the network conditions. Third, we propose a novel resource allocation scheme to adapt media rate to the estimated network bandwidth using each media’s rate-distortion function under various network conditions. By dynamically allocating resources according to network status and media characteristics, we improve the end-to-end quality of services (QoS). Simulation results demonstrate the effectiveness of our proposed schemes. Index Terms—Flow control, multimedia streaming, QoS, rate control, resource allocation, TCP-friendly.

Differentiated service approach has been proposed as a potential solution to provide Quality of Services (QoS) in the next generation Internet. The ultimate goal of end-to-end service differentiation can be achieved by complementing the network-level QoS with the service differentiation at the Internet servers. In this paper, we have presented a detailed study of the performance of service differentiating web servers (SDIS). Various aspects, such as admission control, scheduling, and task assignment schemes for SDIS have been evaluated through real workload traces. The impact of these aspects have been quantified in the simulation-based study. Under high system utilization, a service differentiating server provides significantly better services to high priority tasks compared to a traditional Internet server. A combination of selective early discard and priority-based task scheduling and assignment is required to provide ecient service differentiation at the servers. The results of these studies could be used as a foundation for further studies on service differentiating Internet servers.

The server's storage I/O and network I/O bandwidths are the main bottleneck of VoD service. Multicast offers an efficient means of distributing a video program to multiple clients, thus greatly improving the VoD performance. However, there are many problems to overcome before development of multicast VoD systems. This paper critically evaluates and discusses the recent progress in developing multicast VoD systems. We first present the concept and architecture of multicast VoD, and then introduce the techniques used in multicast VoD systems. We also analyze and evaluate problems related to multicast VoD service. Finally, we present open issues on multicast VoD as possible future research directions.

Resource reservation must operate in an efficient and scalable fashion, to accommodate the rapid growth of the Internet. In this paper, we describe a distributed architecture for inter-domain aggregated resource reservation for unicast traffic. We also present an associated protocol, called the Border Gateway Reservation Protocol (BGRP), that scales well, in terms of message processing load, state storage and bandwidth. Each stub or transit domain may use its own intra-domain resource reservation protocol. BGRP builds a sink tree for each of the stub domains. Each sink tree aggregates bandwidth reservations from all data sources in the network. Since backbone routers maintain only the sink tree information, the total number of reservations at each router scales linearly with the number of Internet domains N . (Even aggregated versions of the current protocol RSVP have a reservation count that can grow like O(N 2 ).) BGRP maintains these aggregated reservations using "soft state." To further reduce the protocol message traffic, routers may reserve bandwidth beyond the current load, so that some sources can join or leave the tree without sending messages all the way to the tree root. BGRP relies on Differentiated Services for data forwarding, hence the number of packet classifier entries is extremely small.

The rapid proliferation of the Internet in the last few years has given rise to a strong interest in carrying telephony over the Internet. Because the Internet supports data communications, a range of other services can be bundled together with Internet telephony. The Internet, however, was designed for non-real-time data communications, and hence it poses several technical challenges that must be overcome before the Internet can be successfully used for carrying telephone services. This article discusses new services we can expect from Internet telephony, the technical challenges and solutions, and the emerging products that promise to support Internet telephony. INTRODUCTION Circuit switching and packet switching are the two main technologies for computer and telecommunications networks. The current telephone system is based on circuit switching, which offers a guaranteed quality of service (QoS) to customers. A circuit has to be set up between two endpoints before the start...

Given the ever increasing demand for network bandwidth, and the recent phenomenal advances in optical wavelength division multiplexing (WDM) networking technologies, a major component of the Next Generation Internet will be an Internat protocol (IP)-based optical WDM network. As IP over WDM networking technologies mature, a number of important architectural, management and control issues have surfaced. These issues need to be addressed before a true Next Generation Optical Internet can emerge. In this paper, we enumerate some of the key architectural, management and control issues and discuss corresponding approaches and advances made toward addressing these issues. We first review the different IP/WDM networking architectural models and their tradeoffs. We outline and discuss several management and control issues and corresponding approaches related to the configuration, fault, and performance management of IP over dynamic WDM networks. We present an analysis and supporting simulation results demonstrating the potential benefits of dynamic IP over WDM networks. We then discuss the issues related to IP/WDM traffic engineering in more detail, and present the approach taken in the NGI SuperNet Network Control and Management Project funded by DARPA. In particular, we motivate and present an innovative integrated traffic-engineering framework for reconfigurable IP/WDM networks. It builds on the strength of multiprotocol label switching for fine-grain IP load balancing, and on the strength of reconfigurable WDM networking for reducing the IP network’s weighted-hop-distance, and for expanding the bottleneck bandwidth.

The Integrated Services Packet Network (ISPN) architecture proposed within the Internet community [2] incorporates a resource reservation mechanism for those applications requiring Quality of Service (QoS) guarantees. Resource reservation introduces a new form of resource contention that can lead to reduced network throughput and thrashing. We establish several necessary conditions to induce thrashing. We also look at the effects several different reservation models and user behaviors can have on network stability. Our work is unique from previous network resource reservation investigations in that we consider the effects of reservations for multipoint-to-multipoint applications. We conclude with examples of how simple modifications to user behavior can result in significant increases in system stability. 1 Introduction The Internet, and other similar packet-switched network architectures, offer best-effort service. Best-effort service requires no admission control and involves no re...