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HTTP Latency

  To get a sense for the likelihood that a request would take a long time to start receiving data, we collected 1000 random URLs from AltaVista [1] and timed their responses. This study differs somewhat from Viles and French [20], who studied the availability of random HTTP servers and the time to connect to them; here we are seeing how long it takes to collect the first data from a WWW page. Figure 5 shows the results of this experiment, based on the 722 URLs that returned data within the first minute. We found that about a third of pages responded within a second, assuming they responded at all, and half responded within about 1.6s. However, it takes 5s to cover tex2html_wrap_inline1253 of the pages and 10% took 10-30s or more for the first data to arrive. As more pages on the WWW are dynamically generated, we expect the fraction of pages with sluggish response to increase.

  figure539


Figure 5: Distribution of response times to receive first data, based on a sampling of 722 URLs. Roughly tex2html_wrap_inline1251 of the sample received data within a second, and tex2html_wrap_inline1253 received data within 5 seconds.



Gaurav Banga
Tue Nov 12 20:47:38 EST 1996