Showing papers by "Jon Crowcroft published in 2002"

Forward Error Correction (FEC) Building Block

Abstract: This document generally describes how to use Forward Error Correction (FEC) codes to efficiently provide and/or augment reliability for data transport. The primary focus of this document is the application of FEC codes to one-to-many reliable data transport using IP multicast. This document describes what information is needed to identify a specific FEC code, what information needs to be communicated out-of-band to use the FEC code, and what information is needed in data packets to identify the encoding symbols they carry. The procedures for specifying FEC codes and registering them with the Internet Assigned Numbers Authority (IANA) are also described. This document should be read in conjunction with and uses the terminology of the companion document titled, "The Use of Forward Error Correction (FEC) in Reliable Multicast".

The Use of Forward Error Correction (FEC) in Reliable Multicast

Abstract: This memo describes the use of Forward Error Correction (FEC) codes to efficiently provide and/or augment reliability for one-to-many reliable data transport using IP multicast. One of the key properties of FEC codes in this context is the ability to use the same packets containing FEC data to simultaneously repair different packet loss patterns at multiple receivers. Different classes of FEC codes and some of their basic properties are described and terminology relevant to implementing FEC in a reliable multicast protocol is introduced. Examples are provided of possible abstract formats for packets carrying FEC.

Asynchronous Layered Coding (ALC) Protocol Instantiation

Abstract: This document describes the Asynchronous Layered Coding (ALC) protocol, a massively scalable reliable content delivery protocol. Asynchronous Layered Coding combines the Layered Coding Transport (LCT) building block, a multiple rate congestion control building block and the Forward Error Correction (FEC) building block to provide congestion controlled reliable asynchronous delivery of content to an unlimited number of concurrent receivers from a single sender.

Layered Coding Transport (LCT) Building Block

Abstract: Layered Coding Transport (LCT) provides transport level support for reliable content delivery and stream delivery protocols. LCT is specifically designed to support protocols using IP multicast, but also provides support to protocols that use unicast. LCT is compatible with congestion control that provides multiple rate delivery to receivers and is also compatible with coding techniques that provide reliable delivery of content.

Peer to peer: peering into the future

Abstract: In this paper, we survey recent work on peer-to-peer systems, and venture some opinions about future requirements for research.The paper is a survey to support the tutorial at the Networks 2002 Conference and is therefore neither complete, nor likely to be up-to-date by the time you are reading this, since the topic was extremely fast-evolving at the time of writing.Instead, we try to bring some historical perspective and structure to the area, and to shed light on where the novel contributions, and where it is likely that there are research questions to answer.

ATM: a retrospective on systems legacy or "a technology with a fabulous future behind it?"

Abstract: The following four papers were selected from submissions for a proposed workshop that was to have been held during the 2002 ACM SIGCOMM Conference. Due to time, we cancelled the event, but the papers capture some of the past, present and future lessons to be gleaned from the whole ATM experience, and we felt that these lessons should be provided with a forum.

A Delay Bound alternative revision of RFC 2598

Abstract: For historical interest, this document captures the EF Design Team's proposed solution, preferred by the original authors of RFC 2598 but not adopted by the working group in December 2000. The original definition of EF was based on comparison of forwarding on an unloaded network. This experimental Delay Bound (DB) PHB requires a bound on the delay of packets due to other traffic in the network. At the Pittsburgh IETF meeting in August 2000, the Differentiated Services working group faced serious questions regarding RFC 2598 - the group's standards track definition of the Expedited Forwarding (EF) Per Hop Behavior (PHB). An 'EF Design Team' volunteered to develop a re-expression of RFC 2598, bearing in mind the issues raised in the DiffServ group. At the San Diego IETF meeting in December 2000 the DiffServ working group decided to pursue an alternative re-expression of the EF PHB.

TCP/IP and Linux protocol implementation

Abstract: Vinton Cerf--co-inventor of TCP/IP--is the technical editor for this book. " This remarkable book ought to be titled ' TCP/IP illustrated' !

Channel islands in a reflective ocean: large-scale event distribution in heterogeneous networks

Abstract: We discuss the design of a multicast event distribution service intended to support extremely large-scale event distribution. To date, event notification services have been limited in their scope due to limitations of the infrastructure. At the same time, Internet network and transport layer multicast services have seen limited deployment due to lack of user demand (with the exception of streaming services, e.g., on Sprint's US core network and in the Internet II). Research in active networks and reflective middleware suggests a way to resolve these two problems at one go. The goal of this article is to describe a reflective middleware system that integrates the network, transport, and distributed middleware services into a seamless whole. The system integrates this "low-level" technology into an event middleware system, suitable for telemetry, novel mobile network services, and other as yet unforeseen applications.

Internet Multicast Tomorrow

Abstract: This article is part of a pair, the first of which looked at the state of play in IP multicast routing (Ole: IPJ Citation?) In this article, we look at the broader problems and future activities with multicast We divide the areas into routing, addressing, transport, security, operations, and research There has been quite a bit of debate about the nature of compelling applications for multicast recently[44] It is certainly the case that we do not completely understand the “market” for multicast this is at least in part because multicast does not yet provide a complete set of functions for all the applications and services we might imagine This is a typical chicken and egg situation, though: To put an extreme version of the argument, the application writers don’t see any multicast deployed; the ISPs don’t see any multicast applications; the router vendors don’t see any multicast service demand from ISPs1 As we discussed in the part I of this article, this vicious circle has been broken by streaming applications for audio and video from the classical content providers in the entertainment and news industries However we are still seeing some teething problems However, we are also seeing broader interest and development The next section presents recent work on routing and addressing After that we look at transport Subsequently, we discuss security Then we look at operations and management Finally, we take a glance at some of the research ideas that are out there

Channel Islands in a Reflective Ocean: Large Scale Event Distribution in Heterogeneous Networks

Abstract: This is a discussion paper about the possible future use of network and transport level multicast services to support extremely large scale event distribution.To date, event notification services[40] have been limited in their scope due to limitations of the infrastructure At the same time, Internet network and transport layer multicast services have seen limited deployment due to lack of user demand (with the exception more recently of streaming services, e.g. on Sprint's US core network, and in the Internet II). Recent research in active and reflective middleware suggests a way to resolve these two problems at one go.Event-driven and messaging infrastructures are emerging as the most flexible and feasible solution for enabling rapid and dynamic integration of legacy and monolithic software applications into distributed systems. Event infrastructures also support deployment and evolution of traditionally difficult-to-build active systems such as large-scale collaborative environments and mobility aware architectures.Event notification is concerned with propagation of state changes in objects in the form of events. A crucial aspect of events is that they occur asynchronously. Event consumers have no control over when events are triggered. On the other hand, event suppliers do not generally know what entities might be interested in the events they provide. These two aspects clearly define event notification as a model of asynchronous and de-coupled communication, where entities communicate in order to exchange information, but do not directly control each other.The IETF is just finishing specifying a family of reliable multicast transport protocols, for most of which there are pilot implementations. Key amongst these for the purposes of this research is the exposure to end systems of router filter functionality in a programmable way, known as Generic Router Assist. This is an inherent part of the Pragmatic General Multicast service, implemented by Reuters, Tibco and Cisco in their products, although it has not been widely known or used outside of the TIBNET products until very recently.The goal of this paper is to describe a reflective middleware system that integrates the network, transport and distributed middleware services into a seamless whole.The outcome of this research will be to integrate this 'low-level' technology into an event middleware system, as a toolkit as well as evaluation of this approach for massive scale event notification, suitable for telemetry, novel mobile network services, and other as yet unforeseen applications.

Proactive multi-path routing

Abstract: Internet service provider faces a daunting challenge in provisioning network efficiently. We introduce a proactive multipath routing scheme that tries to route traffic according to its built-in properties. Based on mathematical analysis, our approach disperses incoming traffic flows onto multiple paths according to path qualities. Long-lived flows are detected and migrated to the shortest path if their QoS could be guaranteed there. Suggesting nondisjoint path set, four types of dispersion policies are analyzed, and flow classification policy which relates flow trigger with link state update period is investigated. Simulation experiments show that our approach outperforms traditional single path routing significantly.

Securing the Internet metering and billing

Abstract: In the near future, billing for network services will not only be concerned with time or volume based accounting but also in ways of measuring the quality of the service provided. Dynamic price schemes, such as congestion-based charging, have been proposed. In some of these models, the charging infrastructure relies on the distribution of electronic tariffs to end-users machines. The tariff structure includes the price information and an algorithm to calculate the charge. Thus, the monitoring of network usage according to this tariff is essential within these frameworks. However, little attention has been given to the security issues associated with Internet metering in these schemes. This has had a great impact on the new models proposed today, since security has become a major concern in open networks. Systems that naturally have incentive to fraud, such as metering systems used for billing purposes, must deal with security threats in large scale environments. The article compiles the security issues of a dynamic networked system where electronic tariffs and service level agreement (SLA) structures are distributed among service providers and customers. To address these issues, a set of security protocols is outlined.