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Cisco Cache Engine


The Cisco Cache Engine performs shared network caching of  Web  content to eliminate repeated transmission of identical content over wide-area network (WAN) links. The  solution includes high-performance Cisco Cache Engines that communicate with Cisco IOS® routers using the Cisco  Web Cache Control Protocol.

WAN Traffic Congestion and the Caching Solution

Companies rely upon Web access for a range of mission-critical business functions. As a result of the overwhelming growth of Web traffic, network administrators face the need to spend more money on WAN access bandwidth and service. Yet, a lot of  Web traffic can be redundant---multiple users at any given site request the same content. With the Cache Engine, Cisco has seized the opportunity to intelligently reduce bandwidth usage and  improve network response time. The Cache Engine dynamically retrieves, stores, and serves Web content locally to  eliminate redundant Web traffic and provide faster Web  access.

In operation, when a user first requests particular Web content, the Cache Engine intercepts the request, fetches the Web page from the remote server, and sends the content to the user while simultaneously storing the content locally. The system satisfies subsequent requests for the same content from local storage. The Cache Engine has the built-in intelligence to determine what can and should be cached. (For  example, stock price data is not cached, but the banners and buttons on the stock quotation Web page are cached for  a configurable period). The Cache Engine can also dynamically refresh content stored locally. The result is  much higher-performance Web access for the end user, with a significant reduction in WAN traffic volume.

Features at a Glance

The Cache Engine offers the following features:


By reducing the amount of traffic on WAN links and on  overburdened Web servers, caching provides significant benefits to service providers, enterprise networks, and end users.

Technology Overview

The Cisco Cache Engine is a robust, high-performance Web cache solution that provides for ease of  deployment and very low cost of ownership. The system leverages the large installed base of Cisco IOS routers to further increase the  value of enterprise and service provider customers' investments in Cisco equipment. The system was designed from the ground up as a loosely coupled, multinode network system optimized to provide robust, high-performance class, shared-network caching.

The solution comprises the Web Cache  Control Protocol (a standard feature of Cisco IOS software) and one  or more Cisco Cache Engines that store and retrieve cached data  locally.


In operation, a Cisco IOS router sends all Web requests to  the  Cache Engine without requiring any changes to client browsers---caching is entirely transparent. The first time a  particular Web page is requested, the Cache Engine sends the request to the Web server and forwards the resulting content to the requester while storing the content. All subsequent requests for the same content are fulfilled by the  Cache Engine, eliminating that traffic from the WAN link. The end  user notices only that Web page access times  improve.

Figure 1 shows a solution that incorporates a  four-Cache Engine cache farm. When customers add Cache Engines to scale a  cache farm, each additional engine takes on  an equal portion of the stored data. For example, a single Cache Engine provides 24 GB of storage and 2000 concurrent sessions; two Cache Engines provide 48  GB of storage and  4000 concurrent sessions. A single cache farm can scale to 32 Cache Engines, providing 768 GB of  cache storage and  64,000 concurrent sessions.
Figure 1: The Cache Engine is connected directly to the router


Large Web caches are used primarily by service providers and  institutions with hundreds of users, for example, universities, large enterprises, and Internet gateway sites around the world. Because so much Internet content is currently located in North America, international institutions use Web caching to extract maximum benefit from costly transoceanic links. ISPs can deploy cache farms hierarchically to gain the benefits of caching at each level of their network infrastructures, as shown in Figure 2.
Figure 2: Deployment of Cache Engine Cache Farms for an ISP

Small and medium-sized businesses and branch offices can use the  Cache Engine to cache Internet and intranet Web  servers at both a central site and remote offices. (See  Figure  3.) This hierarchical implementation reduces congestion at central servers and frees bandwidth on intersite  links.
Figure 3: Enterprise Deployment of Cache Engines

Service and Support Options

Service and support for the Cache Engine are available on a  one-time or annual contract basis. Support ranges from help-desk assistance to proactive, onsite consultation. All support contracts include major Cisco IOS software updates, full access rights to Cisco Connection Online, and 24-hour-a-day technical assistance. Contact your  local sales  office for further information.

Availability and Orderability

The Cache Engine is generally availability. Table 1 lists orderable products of the Cache Engine:

Table 1: Cache Engine Products 

Product Number  Product Description 
Cache Engine CE2050 24-GB/2000-session Cache Engine
Posted: Thu Oct 15 07:44:44 PDT 1998

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