ICAP is an open standard protocol that extends the NetCache content delivery model by enabling value-added services. ICAP leverages the existing network infrastructure and makes it easy to implement third-party applications that provide services such as content filtering, virus scanning, language translation, and ad insertion.
ICAP functionality extends your network to provide content management services. It increases network efficiency and provides scalable solutions for processing Internet-based content. Because ICAP is an open protocol, you can extend ICAP servers to provide new services at the edge of any network. ICAP is extensible, efficient, and scalable.
The ICAP open standard allows you to choose applications without being locked into a proprietary, single solution for value-added services such as virus scanning.
Modified content is cached, eliminating the need to fetch a new copy or reprocess a request. The ICAP protocol directs or "vectors" specific content from NetCache to dedicated ICAP servers for adaptation. Vectoring frees up cache resources by pipelining process-intensive applications that consume bandwidth off the cache.
ICAP is a scalable solution because deploying ICAP services is more efficient than adding a Web proxy to a network gateway for each service. In addition, several ICAP servers configured to provide the same type of service, such as, virus scanning, can service requests from a single cache.
NetCache and ICAP work together to provide the following types of services:
Virus scanning services check Internet content for the presence of virus contamination. ICAP supports virus checking or scanning for HTTP and FTP content. When an ICAP server is installed and enabled in a caching system, all Web transactions are directed to the ICAP server. The ICAP server performs the virus checking service, and then returns the request to the NetCache appliance.
Note
ICAP virus scanning services are not supported for secure sockets (SSL). SSL is a secure connection, and data received over an SSL connection cannot be interpreted by NetCache or an ICAP server.
Content filtering services monitor Internet access to content by category, and redirect unauthorized or restricted requests to another Web site. Categorization provides a cache of URL-to-category mapping information that can be used in combination with NetCache ACLs to enforce category restrictions, that is, to control user requests for content. ICAP supports the following content filtering features:
Ad insertion services use click streams to profile users based on content retrieval. This information is then used for target advertising. Ad insertion techniques paste advertisements into Web pages as an effective means of connecting customers to products and merchants.
There are two ad insertion techniques: intrapage insertion and interpage insertion.
With this technique, an advertisement is pasted directly into an HTML page. These types of banner ads direct users to various Web pages. This application requires content filtering so that only HTML pages are redirected to an ad insertion service.
With this technique, Web pages are inserted into the click/result stream at random intervals. The Web pages contain links to the original content. These types of ads are difficult or impossible to avoid by narrowing the browser window. They appear for 8 to 10 seconds, then users are redirected to the original link they wanted to access.
A targeted ad system can create ads tailored to the user. This type of ad system can identify a user by an IP address or authentication information to create a profile of the user. Access is recorded in ICAP log files so that ad vendors can obtain a count of how many times an ad has appeared.
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Part No. 210-00263
File: icap102.htm
Last updated: 07/30/02 12:00:23