Html js img css img html img an example web page

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: server –  Based on 8mestamp of copy such as “Last- Modified” header from server –  Or based on content of copy such as “Etag” header from server –  Content is available aher 1 RTT Cache Network Server 143 25 11/26/13 Web Caching (4) •  Pu‚ng the pieces together: 144 Introduc8on to Computer Networks CDNs (Content Delivery Networks) (§7.5.3) Computer Science & Engineering 26 11/26/13 Context •  As the web took off in the 90s, traffic volumes grew and grew. This: 1.  Concentrated load on popular servers 2.  Led to congested networks and need to provision more bandwidth 3.  Gave a poor user experience •  Idea: –  Place popular content near clients –  Helps with all three issues above 148 Popularity of Content •  Zipf’s Law: few popular items, many unpopular ones; both mafer George Zipf (1902- 1950) Zipf popularity (kth item is 1/k) Rank Source: Wikipedia 151 27 11/26/13 Content Delivery Network 153 Content Delivery Network (2) •  DNS resolu8on of site gives different answers to clients –  Tell each client the site is the nearest replica (map client IP) 154 28 11/26/13 Business Model •  Clever model pioneered by Akamai –  Placing site replica at an ISP is win- win –  Improves site experience and reduces bandwidth usage of ISP Consumer site ISP Replica User . . . User 155 Topic •  The Future of HTTP –  How will we make the web faster? –  A brief look at some approaches request Network 156 29 11/26/13 Modern Web Pages •  Waterfall diagram shows...
View Full Document

Ask a homework question - tutors are online