Java-Based Adaptive Web Caching CS-526 Fall 2002 Semester Project G. Williams

Adaptive Web Caching Related Work - Lixia Zhang, Sally Floyd, and Van Jacobson, "Adaptive Web Caching," April 25, Problem - Data dissemination to thousands or millions of users on the Internet. Solution - Web Multicasting and Caching

Adaptive Web Caching IP multicast serves two purposes The most efficient way to deliver the same data to multiple receivers. An information discovery vehicle. For example, a host can multicast a query to a relevant group when it does not know exactly whom to ask.

Proposed Approach Researched some exisiting “Adaptive” caching servers, primarily Squid. Developed an Adaptive Web Caching (Proxy) Server “proof-of-concept” based on ideas from Zhang, Floyd, and Van Jacobson.

Custom Enhancements Web servers don’t need to implement multicasting to deliver content - This allows existing web servers on the Internet to be used with the system Servers share cached content dynamically – Local Cache is populated by snooping data being sent amongst servers in the multicast group.

Sample Configuration # Multicast Proxy Server Configuration File # Port Number, Default 8080 Port 8080 # Cache Directory CacheRoot=cache # Default TTL for a cached document in minutes CacheDefaultExpire 15 # Multicast Group Address MulticastGroupAddress # Multicast port on which to send requests MulticastRequestPort 1234 # Multicast port on which to receive replies MulticastResponsePort 6789 # The maximum time in milliseconds to wait for a response before # retrieving the document from the origin server. MaxResponseWaitTime 500

“Proof-of-Concept” Test Cases Stand-Alone Server No Multicasting Multiple Cache Updates two or more instances sharing cache data Retrieve Content from Group Request from neighbors before contacting the origin server Adaptive Caching Adding more servers to a group, no changes required – system adapts.

References Project Web Page (Source Code, Documentation etc.) [FLOYD97] Lixia Zhang, Sally Floyd, and Van Jacobson, "Adaptive Web Caching," April 25, [RFC 2616] Hypertext Transfer Protocol - HTTP/1.1, Request for Comments [RFC 1112] Host Extensions for IP Multicasting, Request for Comments [IANA]: Internet Assigned Number Authority, Internet Multicast Addresses [SQUID02] Squid Web Proxy Cache