Clarifying the fundamentals of HTTP

ABSTRACT

The simplicity of HTTP was a major factor in the success of the Web. However, as both the protocol and its uses have evolved, HTTP has grown complex. This complexity results in numerous problems, including confused implementors, interoperability failures, difficulty in extending the protocol, and a long specification without much documented rationale.Many of the problems with HTTP can be traced to unfortunate choices about fundamental definitions and models. This paper analyzes the current (HTTP/1.1) protocol design, showing how it fails in certain cases, and how to improve these fundamentals. Some problems with HTTP can be fixed simply by adopting new models and terminology, allowing us to think more clearly about implementations and extensions. Other problems require explicit (but compatible) protocol changes.

REFERENCES

• 1: M. Baker. An abstract model for HTTP resource state. Internet-Draft draft-baker-http-resource-state-model-01.txt, IETF, Nov. 2001. This is a work in progress. http://www.ietf.org/internet-drafts/draft-baker-http-resource-state-model-01.txt.
• 2: T. Berners-Lee. Hypertext transfer protocol (HTTP). Internet Draft draft-ietf-iiir-http-00.txt, IETF, Nov. 1993. This is a work in progress. ftp://ftp.std.com/obi/Networking/WWW/draft-ietf-iiir-http-00.txt.
• 3: Marjory S. Blumenthal , David D. Clark, Rethinking the design of the Internet: the end-to-end arguments vs. the brave new world, ACM Transactions on Internet Technology (TOIT), v.1 n.1, p.70-109, Aug. 2001 [doi>10.1145/383034.383037]
• 4: M. C. Chan and T. Woo. Cache-based compaction: A new technique for optimizing Web transfer. In Proc. IEEE Infocom '99, pages 117--125, New York, NY, March 1999.
• 5: J. Dilley. The effect of consistency on cache response time. IEEE Network, 14(3):24--28, May/June 2000.
• 6: F. Douglis, A. Feldmann, B. Krishnamurthy, and J. Mogul. Rate of change and other metrics: a live study of the World Wide Web. In Proc. Symp. on Internet Technologies and Systems, pages 147--158, Monterey, CA, Dec. 1997. USENIX.
• 7: D. E. Eastlake 3rd. Protocol versus document points of view. Internet-Draft draft-eastlake-proto-doc-pov-04.txt, IETF, Sep. 2001. This is a work in progress. http://www.ietf.org/internet-drafts/draft-eastlake-proto-doc-pov-04.txt.
• 8: A. Einstein. Widely attributed quotation. Various forms of this quotation are attributed to Einstein.
• 9: R. T. Fielding, J. Gettys, J. C. Mogul, H. Frystyk Nielsen, and T. Berners-Lee. Hypertext transfer protocol -- HTTP/1.1. RFC 2068, HTTP Working Group, Jan. 1997.
• 10: R. T. Fielding, J. Gettys, J. C. Mogul, H. Frystyk Nielsen, L. Masinter, P. Leach, and T. Berners-Lee. Hypertext transfer protocol -- HTTP/1.1. RFC 2616, HTTP Working Group, June 1999.
• 11: Roy T. Fielding , Richard N. Taylor, Principled design of the modern Web architecture, Proceedings of the 22nd international conference on Software engineering, p.407-416, June 04-11, 2000, Limerick, Ireland [doi>10.1145/337180.337228]
• 12: N. Freed and N. Borenstein. Multipurpose internet mail extensions (MIME) part one: Format of Internet message bodies. RFC 2045, Network Working Group, Nov. 1996.
• 13: H. Frystyk Nielsen, P. J. Leach, and S. Lawrence. An HTTP extension framework. RFC 2774, IETF, Feb. 2000.
• 14: H. Frystyk Nielsen, M. Spreitzer, B. Janssen, and J. Gettys. HTTP-NG overview: Problem statement, requirements, and solution outline. Internet Draft draft-frystyk-httpng-overview-00.txt, IETF, Nov. 1998. This is a work in progress. http://www.w3.org/Protocols/HTTP-NG/1998/11/draft-frystyk-httpng-overview-00.
• 15: Y. Goland, E. Whitehead, Jr, A. Faizi, S. Carter, and D. Jensen. HTTP extensions for distributed authoring -- WEBDAV. RFC 2518, IETF, Feb. 1999.
• 16: K. Holtman. The Safe response header field. RFC 2310, IETF, April 1998.
• 17: Barron C. Housel , David B. Lindquist, WebExpress: a system for optimizing Web browsing in a wireless environment, Proceedings of the 2nd annual international conference on Mobile computing and networking, p.108-116, November 1996, Rye, New York, United States [doi>10.1145/236387.236416]
• 18: Internet Architecture Board. IAB architectural and policy considerations for OPES. Internet Draft draft-iab-opes-01.txt, IETF, Oct. 2001. This is a work in progress.
• 19: G. Klyne and L. Masinter. Identifying composite media features. Internet Draft draft-ietf-conneg-feature-hash-03.txt, IETF CONNEG Working Group, July 1999. This is a work in progress. http://www1.ics.uci.edu/pub/ietf/http/draft-ietf-conneg-feature-hash-03.txt.
• 20: B. Krishnamurthy and M. Arlitt. PRO-COW: Protocol compliance on the web. In Proc. USENIX Symposium on Internet Technology and Systems, pages 109--122, San Francisco, CA, March 2001.
• 21: D. M. Kristol and L. Montulli. HTTP state management mechanism. RFC 2965, IETF, Oct. 2000.
• 22: D. Li, P. Cao, and M. Dahlin. WCIP: Web cache invalidation protocol. Internet Draft draft-danli-wrec-wcip-01.txt, IETF, March 2001. This is a work in progress. http://www.ietf.org/internet-drafts/draft-danli-wrec-wcip-01.txt.
• 23: Merriam-Webster. Webster's Seventh New Collegiate Dictionary. G. & C. Merriam Co., Springfield, MA, 1963.
• 24: J. Mogul, J. Cohen, and S. Lawrence. Specification of HTTP/1.1 OPTIONS messages. Internet Draft draft-ietf-http-options-02.txt, HTTP Working Group, Aug. 1997. This is a work in progress. http://www1.ics.uci.edu/pub/ietf/http/draft-ietf-http-options-02.txt.
• 25: J. C. Mogul. Server-directed transcoding. Computer Communications, 24(2):155--162, Feb. 2001.
• 26: Jeffrey C. Mogul , Fred Douglis , Anja Feldmann , Balachander Krishnamurthy, Potential benefits of delta encoding and data compression for HTTP, Proceedings of the ACM SIGCOMM '97 conference on Applications, technologies, architectures, and protocols for computer communication, p.181-194, September 14-18, 1997, Cannes, France
• 27: J. C. Mogul, R. T. Fielding, J. Gettys, and H. Frystyk Nielsen. Use and interpretation of HTTP version numbers. RFC 2145, HTTP Working Group, May 1997.
• 28: J. C. Mogul, B. Krishnamurthy, F. Douglis, A. Feldmann, Y. Goland, A. van Hoff, and D. Hellerstein. Delta encoding in HTTP. RFC 3229, IETF, Jan. 2002.
• 29: E. Rescorla and A. M. Schiffman. The Secure HyperText Transfer Protocol. RFC 2660, IETF, Aug. 1999.
• 30: J. H. Saltzer , D. P. Reed , D. D. Clark, End-to-end arguments in system design, ACM Transactions on Computer Systems (TOCS), v.2 n.4, p.277-288, Nov. 1984 [doi>10.1145/357401.357402]
• 31: A. Tridgell and P. Mackerras. The rsync algorithm. Technical Report TR-CS-96-05, Dept. of Computer Science, Australian National University, June 1996. http://cs.anu.edu.au/techreports/1996/TR-CS-96-05.html.

INDEX TERMS

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

General Terms:
Design

Keywords:
HTTP, protocol design