(C) Copyright PodsCat, 1998 A Smart Internet Caching System1 E-mail : [email protected]...

(C) Copyright PodsCat, 1998

A Smart Internet Caching System 1

A Smart Internet Caching System

E-mail : [email protected]

Director : Dr. 張燕光

Speaker : Chun-Po Kuo

From : http://info.isoc.org/isoc/whatis/conferences/inet/96/proceedings/a4/a4_3.htm



Outline

Introduction Background and previous work System Model System design System Protocols Dimensioning and performance issues Conclusions



Introduction

long response time due to: load on the server load on the communication line

system techniques are: Caching of recently accessed file Pre-fetching of files which may be accessed shortly. Deferment of loading large and/or low priority files. Automatic updating of frequently used pages during off-peak times. File compression and difference.



Background and previous work

Two techniques used to implement proxies are mirroring, and caching.

Mirror suffers from a number of drawbacks : Files are mirrored only at periodic intervals.

Many mirrored files will rarely, or never, be accessed.

Users may not be aware of the best mirror site to use.

A mirror can only store a small fraction of the files on the Internet.



The System Model



Performance-enhancing measures

A number of techniques are used to improve performance. A conventional cache File pre-fetching Deferred file loading Automatic updating File compression and differencing

three types of document requests User requests Predicted request Update requests



System Model



Algorithm for the local gateway

The prime responsibilities of the local gateway are :Record all user requests, and maintain a history

information of previous requests.

Maintain a cache of recently loaded document.

Decide which documents are required for the predicted and update requests.

Transmit predicted and update requests for documents to the remote gateway.

Receive and decompress documents.

Forward documents to user.



Local Gateway



Algorithms for the remote gateway

The prime responsibilities of the remote gateway are :Receive requests from local gateway

Requests and load documents from WWW servers or other caches.

Use heuristics to predict which other documents might soon be requested on the basis of the contents of requests document.

Compress these documents will not have yet been requested, in which case a push or forces send is required.



Remote Gateway



Conclusion

Detailed analysis and experimentation is required.

Having demonstrated their feasibility , a product could be developed for wider implementation.

(C) Copyright PodsCat, 1998 A Smart Internet Caching System1 E-mail : [email protected]...

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