A web-based resource migration protocol using WebDAV

ABSTRACT

The web's hyperlinks are notoriously brittle, and break whenever a resource migrates. One solution to this problem is a transparent resource migration mechanism, which separates a resource's location from its identity, and helps provide referential integrity. However, although several such mechanisms have been designed, they have not been widely adopted, due largely to a lack of compliance with current web standards. In addition, these mechanisms must be updated manually whenever a resource migrates, limiting their effectiveness for large web sites. Recently, however, new web protocols such as WebDAV (Web Distributed Authoring and Versioning) have emerged, which extend the HTTP protocol and provide a new level of control over web resources. In this paper, we show how we have used these protocols in the design of a new Resource Migration Protocol (RMP), which enables transparent resource migration across standard web servers. The RMP works with a new resource migration mechanism we have developed called the Resource Locator Service (RLS), and is fully backwards compatible with the web's architecture, enabling all web servers and all web content to be involved in the migration process. We describe the protocol and the new RLS in full, together with a prototype implementation and demonstration applications that we have developed. The paper concludes by presenting performance data taken from the prototype that show how the RLS will scale well beyond the size of today's web.

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INDEX TERMS

Primary Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.2 Network Protocols
          Subjects: Applications (SMTP, FTP, etc.)

Additional Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.4 Distributed Systems
          Subjects: Client/server; Distributed applications

  H. Information Systems
  H.3 INFORMATION STORAGE AND RETRIEVAL
      H.3.5 On-line Information Services
          Subjects: Web-based services

General Terms:
Algorithms, Design, Experimentation

Keywords:
WebDAV, link rot, referential integrity, resource locator service, resource migration protocol, web