Rohit Khare

Extending the Representational State Transfer (REST) architectural style for decentralized systems

Because it takes time and trust to establish agreement, traditional consensus-based architectural styles cannot safely accommodate resources that change faster than it takes to transmit notification of that change, nor resources that must be shared across independent agencies. The alternative is decentralization: permitting independent agencies to make their own decisions. Our definition contrasts with that of distribution, in which several agents share control of a single decision. Ultimately, the physical limits of network latency and the social limits of independent agency call for solutions that can accommodate multiple values for the same variable. Our approach to this challenge is architectural: proposing constraints on the configuration of components and connectors to induce particular desired properties of the whole application. Specifically, we present, implement, and evaluate variations of the World Wide Webs Representational State Transfer (REST) architectural style that support distributed and decentralized systems.

The origin of (document) species

Abstract The World Wide Webs extraordinary reach is based in part on its open assimilation of document formats. Although Web transfer protocols and addressing can accommodate any kinds of resources, the unique application context of a truly global hypermedia system favours the adoption of certain Web-adapted formats. In this paper we consider the evolutionary record that has led to the ascent of the eXtensible Markup Language (XML). We present a taxonomy of document species in the Web according to their syntax, style, structure, and semanties. We observe the preferential adoption of SGML, CSS, HTML, and XML, respectively, which leverage a parsimonious evolutionary strategy favouring declarative encodings over Turing-complete languages; separable styles over inline formatting; declarative markup over presentational markup; and well-defined semantics over operational behavior. The paper concludes with an evolutionary walkthrough of citation formats. Ultimately, combined with the self-referential power of the Web to document itself, we believe XML can catalyze a critical shift of the Web from a global information space into a universal knowledge network.

Trust management on the World Wide Web

Abstract As once-proprietary mission-specific information systems migrate onto the Web, traditional security analysis cannot sufficiently protect each subsystem atomically. The Web encourages open. decentralized systems that span multiple administrative domains. Trust Management is an emerging framework for decentralizing security decisions that helps developers and others in asking “why” trust is granted rather than immediately focusing on “how” cryptography can enforce it. In this poster, we summarize the implications of Trust Management to future Web applications.

Anatomy of a URL (and other Internet-scale namespaces. 1)

The author discusses the anatomy of a URL (Uniform Resource Locator). He considers domain names, IP addresses, MAC addresses, phone numbers, path names and names in HTTP messages.

Can XForm transform the Web? Transcending the Web as GUI.II

Designing completely abstract user interfaces for the Web requires addressing three separable aspects: presentation, logic and data. Our virtual assistant needs to know how to: prompt the user; do so in a specific order; and recognize spoken or typed entries. The first layer, presentation, addresses rendition of interactors, whether as GUI widgets, voice prompts, or paper blanks. Second, the logical layer governs the order of form field fill-in, multipage and sequenced forms, and scripting for input validation. Finally, the data layer adds more structure and coherency to existing text string-only values by applying richer schemas (types). This kind of coordinated evolution is precisely the mission of the World Wide Web Consortium, whose XForms working group is tackling these interdependent issues. While XHTML brought existing HTML 4.0 usage into XML compliance, XForms was specifically chartered to innovate solutions to support handheld, television, and desktop browsers; deploy richer user interfaces to meet the needs of business, consumer, and device-control applications; improve internationalization; and decouple presentation, logic, and data. The paper considers whether XForm can transform the Web.

Building the perfect beast: dreams of a grand unified protocol

From the infinite world of protocol designs-yet-to-be, the paper focuses on an IETF Birds-of-a-Feather proposal for an Application Core (ApplCore) protocol. ApplCore would identify common problems encountered in application-level protocol development and then design one simple core protocol to solve these problems based on the successes and failures of already deployed IETF protocols-in effect, an application-layer TCP.

TELNET: the mother of all (application) protocols

Telnets true value is not the abstraction of how-to-wire-terminals-to-hosts (standardizing connections); instead, its the abstraction of terminals (standardizing endpoints). Telnets application-level semantics are captured in its external interface, the Network Virtual Terminal. Its internal interfaces have close ties to TCP transport facilities, an option negotiation scheme, and symmetric treatment of client and server roles. Notice that none of these three internal functions has any bearing on remote-login, the most popular application of Telnet. Instead, in considering Telnet against the taxonomic criteria set forth previously, we need to separate Telnet from the services it can access. That helps highlight the enduring lessons of Telnet for future seventh-layer protocol designers.

The spec's in the mail

The paper discusses the coevolution of the Internet Text Message (RFC 822) format and the Simple Mail Transfer Protocol (SMTP, RFC 821), from its roots as a printer-spooling convention piggybacked on FTP through the development of the Multipurpose Internet Mail Extensions (MIME) up to the latest drafts of the Detailed Revision/Update of Message Standards (DRUMS) working group.

Reflections on: Trust management on the World Wide Web

This paper is included in the First Monday Special Issue #6: Commercial applications of the Internet, published in July 2006. Special Issue editor Mark A. Fox asked authors to submit additional comments regarding their articles.

The transfer protocols

There are many Internet-scale messaging systems: Telnet for duplex byte streams, File Transfer Protocol (FTP) for pulling files, Simple Mail Transfer Protocol (SMTP) for reliable e-mail messaging, Network News Transfer Protocol (NNTP) for pushing e-mail, HyperText Transfer Protocol (HTTP) for pulling Web pages, and a host of other special-purpose schemes, from Finger to Network File System (NFS). How can we make sense of it all? Understanding the history of these transfer protocols (TPs) is the key to charting their future, especially as new contenders like HTTP-NG (next-generation) emerge. In this article, I set forth a general ontology-a vocabulary for describing and classifying TPs, with the aim of developing a framework to help navigate among the alternatives.