David M. Kristol

TeleWeb: loosely connected access to the World Wide Web

Abstract The development of the World Wide Web (WWW) has made people reliant on continuous, high-speed, low-cost networks in order to get work done. Ideally, one should be able to browse the Web anytime, anywhere, whether connected to such a network or not. This paper describes the design of TeleWeb, a system we are building to support this goal. We believe that fine-grained cost control is crucial and have developed a “reactive architecture” that supports user-specified adaptation under various operating conditions. There are four key features to TeleWebs architecture: costs are made visible to the user through annotated HTML; budget monitoring warns the user when operations exceed pre-specified limits; actions may be postponed and later triggered when conditions are met; and finally, user customization and system configuration values may automatically adapt according to the changing conditions of use. These mechanisms work together to provide an asynchronous, email-style of browsing in which users can work disconnected from a cache of documents, or trade off communication cost against information needs.

Consistent, yet anonymous, Web access with LPWA

In recent years the World Wide Web WWW has become an immensely popular and powerful medium To attract more users many web sites o er personalized services whereby users identify themselves and register their information preferences On return visits they conveniently receive a personalized selection of information However personalized services raise user concerns with respect to convenience and privacy

Key differences between HTTP/1.0 and HTTP/1.1

Abstract The HTTP/1.1 protocol is the result of four years of discussion and debate among a broad group of Web researchers and developers. It improves upon its phenomenally successful predecessor, HTTP/1.0, in numerous ways. We discuss the differences between HTTP/1.0 and HTTP/1.1, as well as some of the rationale behind these changes.

Conformance testing of protocols specified as communicating finite state machines-a guided random walk based approach

We present a new approach for conformance testing of protocols specified as a collection of communicating finite state machines (FSMs). Our approach uses a guided random walk procedure. This procedure attempts to cover all transitions in the component FSMs. We also introduce the concept of observers that check some aspect of protocol behavior. We present the result of applying our method to two example protocols: full-duplex alternating bit protocol and the ATM-adaptation-layer-convergence protocol. Applying our procedure to the ATM adaptation layer, 99% of component FSMs edges can be covered in a test with 11692 input steps. Previous approaches cannot do conformance test generation for standard protocols (such as asynchronous transfer mode (ATM) adaptation layer) specified as a collection of communicating FSMs.

Multicast transport protocols for high speed networks

This paper presents the design and analysis of three reliable multicast transport protocols for high speed networks. The novelty of these protocols lies in the technique used in combining the acknowledgments of individual destinations along the underlying multicast tree to prevent acknowledgement implosion and in the technique used in preventing unnecessary retransmission by performing local multicasts. These protocols use the periodic exchange of complete state information between the source and the destinations and a block-based Selective Repeat retransmission scheme to improve the overall performance in a high speed networking environment. Performance of each protocol is analyzed in terms of throughput, end-to-end delay, buffer requirement, acknowledgment traffic and retransmission traffic. Based on this analysis and the complexity of implementation, one of the three protocols is recommended for reliable multicasting in high speed networks.<<ETX>>

On secure and pseudonymous client-relationships with multiple servers

This paper introduces a cryptographic engine, Janus, which assists clients in establishing and maintaining secure and pseudonymous relationships with multiple servers. The setting is such that clients reside on a particular subnet (e.g., corporate intranet, ISP) and the servers reside anywhere on the Internet. The Janus engine allows each client-server relationship to use either weak or strong authentication on each interaction. At the same time, each interaction preserves privacy by neither revealing a clients true identity (except for the subnet) nor the set of servers with which a particular client interacts. Furthermore, clients do not need any secure long-term memory, enabling scalability and mobility. The interaction model extends to allow servers to send data back to clients via e-mail at a later date. Hence, our results complement the functionality of current network anonymity tools and remailers. The paper also describes the design and implementation of the Lucent Personalized Web Assistant (LPWA), which is a practical system that provides secure and pseudonymous relations with multiple servers on the Internet. LPWA employs the Janus function to generate site-specific person , which consist of alias usernames, passwords, and e-mail addresses.

A polynomial algorithm for gateway generation from formal specifications

A systematic procedure that takes exponential time to synthesize protocol converters from formal specifications is presented. The algorithm proceeds in two steps: compute the largest common subset of services provided by the two mismatched protocols, and reduce the converter, retaining common services, without traversing the entire machine that represents the composition of the two mismatched protocols. In a number of cases, the converter can be constructed by a memoryless translation of messages from one protocol to another. Conditions under which such stateless conversion is possible are given. Two examples are presented to illustrate the techniques. In the first example, a converter that interconnects a half-duplex protocol with a full-duplex protocol from their formal specifications is computed. In the second example, the polynomial procedure is applied to computation of a converter for interconnecting the SNR and TCP protocols. >