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We describe our investigation of the effect of persistent connections, pipelining and link level document compression on our client and server HTTP implementations. A simple test setup is used to verify H'ITP/l.l's design and understand HTTP/l.1 implementation strategies. We present TCP and real time performance data between the libwww robot [27] and both the W3C's Jigsaw [28] and Apache [29] HTI'P servers using HTI'P/l.O, HTTP/1.1 with persistent connections, HTIPD.1 with pipelined requests, and HTTP/1.1 with pipelined requests and deflate data compression [22]. We also investigate whether the TCP Nagle algorithm has an effect on HllP/I.I performance. While somewhat artificial and possibly overstating the benefits of H'ITP/l.l, we believe the tests and results approximate some common behavior seen in browsers. The results confirm that HTTP/I.1 is meeting its major design goals. Our experience has been that implementation details are very important to achieve all of the benefits of HTI'P/I.l.For all our tests, a pipelined HTTP/1.1 implementation outperformed HTTP/1.0, even when the HTTP/1.0 implementation used multiple connections in parallel, under all network environments tested. The savings were at least a factor of two, and sometimes as much as a factor of ten, in terms of packets transmitted, Elapsed time improvement is less dramatic, and strongly depends on your network connection. Some data is presented showing further savings possible by changes in Web content, specifically by the use of CSS style sheets [lo], and the more compact PNG [2OJ image representation, both recent recommendations of W3C. Time did not allow full end to end data collection on these cases. The results show that H'ITP/l.l and changes in Web content will Permlaslon to moke digital/hard copy of part or all this work for peraonol or classroom use is granted without fee provided that copies ore not made or distributed for profit or commercial advantoge, the copyright notice, the title of the publication and its date appear, and notice is given that copying is by permission of ACM, Inc. To oopy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. SIGCOMM '97 Cannes, France 0 1997 ACM 0.89791.905.X/97/0009...$3.50 have dramatic results in Internet and Web performance as HTTP/1.1 and related technologies deploy over the near future. Universal use of style sheets, even without deployment of I-I'ITP/I.I, would cause a very significant reduction in network traffic.This paper does not investigate further performance and network savings enabled by the improved caching facilities provided by the HTTP/I.1 protocol, or by sophisticated use of range requests.157

No abstract

We describe our investigation of the effect of persistent connections, pipelining and link level document compression on our client and server HTTP implementations. A simple test setup is used to verify H'ITP/l.l's design and understand HTTP/l.1 implementation strategies. We present TCP and real time performance data between the libwww robot [27] and both the W3C's Jigsaw [28] and Apache [29] HTI'P servers using HTI'P/l.O, HTTP/1.1 with persistent connections, HTIPD.1 with pipelined requests, and HTTP/1.1 with pipelined requests and deflate data compression [22]. We also investigate whether the TCP Nagle algorithm has an effect on HllP/I.I performance. While somewhat artificial and possibly overstating the benefits of H'ITP/l.l, we believe the tests and results approximate some common behavior seen in browsers. The results confirm that HTTP/I.1 is meeting its major design goals. Our experience has been that implementation details are very important to achieve all of the benefits of HTI'P/I.l.For all our tests, a pipelined HTTP/1.1 implementation outperformed HTTP/1.0, even when the HTTP/1.0 implementation used multiple connections in parallel, under all network environments tested. The savings were at least a factor of two, and sometimes as much as a factor of ten, in terms of packets transmitted, Elapsed time improvement is less dramatic, and strongly depends on your network connection. Some data is presented showing further savings possible by changes in Web content, specifically by the use of CSS style sheets [lo], and the more compact PNG [2OJ image representation, both recent recommendations of W3C. Time did not allow full end to end data collection on these cases. The results show that H'ITP/l.l and changes in Web content will Permlaslon to moke digital/hard copy of part or all this work for peraonol or classroom use is granted without fee provided that copies ore not made or distributed for profit or commercial advantoge, the copyright notice, the title of the publication and its date appear, and notice is given that copying is by permission of ACM, Inc. To oopy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. SIGCOMM '97 Cannes, France 0 1997 ACM 0.89791.905.X/97/0009...$3.50 have dramatic results in Internet and Web performance as HTTP/1.1 and related technologies deploy over the near future. Universal use of style sheets, even without deployment of I-I'ITP/I.I, would cause a very significant reduction in network traffic.This paper does not investigate further performance and network savings enabled by the improved caching facilities provided by the HTTP/I.1 protocol, or by sophisticated use of range requests.