Cisco Cisco Packet Data Interworking Function (PDIF) Documentation Roadmaps
Content Filtering Support Overview
Category-based Content Filtering Support ▀
Cisco ASR 5000 Series Product Overview ▄
OL-22937-01
Apart from the advantages described previously, Category-based Content Filtering service reduces the requirement of
over-provisioning of capacity at neighboring gateway routers. It also eliminates requirements of external Server Load
Balancers and enhances the accuracy in subscriber charging records.
over-provisioning of capacity at neighboring gateway routers. It also eliminates requirements of external Server Load
Balancers and enhances the accuracy in subscriber charging records.
The Category-based Content Filtering solution has the following logical functions:
Deep Packet Inspection (DPI) for Content Rating (event detection and content extraction)
Content Rating Function with Static Rating of URLs and Dynamic Rating of content
Content Rating Policy Enforcement; for example, permit, discard, deny, redirect
Content-ware accounting CF-EDR generation for events of interest
Static-and-Dynamic Content Filtering
With Static Category-based Content Filtering, the filtering is only as good as the collection of URLs in the database.
Even the largest URL database covers only a fraction of the Surface Web and virtually none of the Deep Web. It is quite
impossible to find, review, and categorize enough of the available Web sites to keep the database current.
Even the largest URL database covers only a fraction of the Surface Web and virtually none of the Deep Web. It is quite
impossible to find, review, and categorize enough of the available Web sites to keep the database current.
Also, many mobile sites are classified as dynamic sites. A dynamic site may return either acceptable or inappropriate
content from the same URL. For example, search engines, news portals, or auction sites that return variable results
depending upon subscriber requests.
content from the same URL. For example, search engines, news portals, or auction sites that return variable results
depending upon subscriber requests.
When the Content Filtering subsystem receives a request for dynamic content it becomes necessary to categorize pages
in real-time to determine how to classify content the provider is delivering at that moment. The ―Static Rating‖ solution
that relies exclusively on previously categorized rating for sites may fail to categorize dynamic sites appropriately.
in real-time to determine how to classify content the provider is delivering at that moment. The ―Static Rating‖ solution
that relies exclusively on previously categorized rating for sites may fail to categorize dynamic sites appropriately.
Dynamic Content Filtering enables on-the-fly content analysis of Web traffic using different content analysis
techniques. When a Web page is received, it is analyzed and then categorized according to the content found in the
page. Whether a Web site has existed for five months or for five minutes does not matter since determination of the
category to which the Web page belongs is made just at the time of request. Therefore, dynamic filters have no problem
keeping up with the growth and changing content of the Internet. A combination of static filtering and dynamic
inspection provides real accuracy and scalability as the Web weaves an increasingly sophisticated network of sites.
techniques. When a Web page is received, it is analyzed and then categorized according to the content found in the
page. Whether a Web site has existed for five months or for five minutes does not matter since determination of the
category to which the Web page belongs is made just at the time of request. Therefore, dynamic filters have no problem
keeping up with the growth and changing content of the Internet. A combination of static filtering and dynamic
inspection provides real accuracy and scalability as the Web weaves an increasingly sophisticated network of sites.
Important:
Category-based Content Filtering can only work in static-only or in static-and-dynamic modes.
Dynamic-only Content Filtering mode is not supported.
In Static-and-Dynamic Content Filtering, every URL will first undergo static rating, if the URL cannot be rated by the
static database, or if the URL‘s statistic rating is categorized as DYNAM, then it will go for dynamic rating. After the
content has been analyzed, as with static content filtering, dynamic rating actions include acceptance, blocking,
redirection, and/or replacement of content.
static database, or if the URL‘s statistic rating is categorized as DYNAM, then it will go for dynamic rating. After the
content has been analyzed, as with static content filtering, dynamic rating actions include acceptance, blocking,
redirection, and/or replacement of content.
Static-and-Dynamic Content Filtering must be enabled at the global and rulebase levels. Before enabling static-and-
dynamic rating in the rulebase, it must be enabled at the global level as the resources required for dynamic rating are
allocated at the global level. When enabled in a rulebase, it is applied for subscribers using that rulebase.
dynamic rating in the rulebase, it must be enabled at the global level as the resources required for dynamic rating are
allocated at the global level. When enabled in a rulebase, it is applied for subscribers using that rulebase.
Limitations of Dynamic Content Filtering