Kiew-Hong Chua a.k.a Francis Computer Network Presentation 12/5/00 NETWORK CACHING TECHNOLOGY Table of Contents: Introduction
Growth of Web Content What is Caching? (benefits & how it woks) Caching Solution on the Network Level Ciscos Network-Based Shared Caching
Introduction The volume of Web traffic on the Internet is staggering, mostly redundancy -- multiple users at any given site request much of the same content. This means that a significant percentage of the WAN infrastructure carries the identical content (and identical requests for it) day after day (e.g: hotmail). Eliminating a significant amount of recurring telecommunications charges offers an enormous savings opportunity for enterprise and service provider customers.
Growth of Web Content Data networking is growing at extreme rate; More than 80% Fortune 500 company have Web site; Mostly implemented intranets with graphically rich data (include scent tech), onto corporate WANs; Resulting uncontrolled growth of Web access requirements to meet bandwidth demand. What is Caching?
A technique of keeping frequently accessed information in a location close to the requester. Web cache stores Web pages and content on a storage device that is physically or logically closer to the user---this is closer and faster than a Web lookup. Reduce amount of traffic on WAN links and overburdened Web server. Provide significant benefits to ISPs, enterprise networks and end users.
2 Key Benefits: Cost savings due to WAN bandwidth reduction : ISP can place place cache engines at (1) strategic points on their networks to improve response times and lower the bandwidth demand on their backbones and (2) strategic WAN access points to serve Web requests from a local disk rather than from distant or overrun Web servers. Increase productivity for end users: > 3 times faster than regular downloading time.
> Improves response times. > Completely transparent to user. How Web caching works? 1. A user accesses a Web page. 2. While the page is being transmitted to the user, the caching system saves the page and all its associated graphics on a local storage device. That content is now cached. 3. Another user (or the original user) accesses that Web page later in the day.
4. Instead of sending the request over the Internet, the Web cache system delivers the Web page from local storage. This process speeds download time for the user, and reduces bandwidth demand on the WAN link. 5. The important task of ensuring that data is up-to-date is depending on the design of the system. Caching Solution on the Network Level Two current types of network-level caching products: > proxy servers,
> network caches. Proxy servers: > not design to optimized for caching, > fail under heavy network loads, > require configuration of each user browser. Network caches: > run under UNIX or WinNT OS that involve very high per process context overhead, they cannot scale to large numbers of simultaneous processes in a graceful fashion.
Ciscos Network-Based Shared Caching Design from the ground up, multinode network system optimized to provide robust shared network caching. The cache engine solution comprises the Web Cache Control Protocol (a standard feature of Cisco IOS software) and one or more Cisco cache engines that store the data in the local network. The Web Cache Control Protocol defines the communication between the cache engine and the router. Using the Web Cache Control Protocol, the router directs only Web requests to the cache engine (rather than to the intended server). The router
also determines cache engine availability, and redirects requests to new cache engines as they are added to an installation. The Cisco cache engine is a single-purpose network appliance that stores and retrieves content using highly optimized caching and retrieval algorithms. > The following picture show a Cisco cache engine connected to a Cisco IOS router. (solely to content mgmt & delivery) This figure provides an overview of the operation of
the cache engine; how it works. Advantages of Cache Engine
Operates transparently to client & network. Client do not need to configure to proxy server mode. Compelling feature for large enterprise & ISP. Scalability, fault-tolerance, and fail-safe operation. High performance. (secure, real-time, eliminate file fragmentation,etc) Hierarchical Use (place anywhere). The following figure shows hierarchical implementation of cache engines (ISP) Conclusion Networking Caching is a very innovative
and practical way of implement economicof-scales at all cause into the Information Systems Technology era. Thank you for your attention
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