Cisco Cisco Packet Data Gateway (PDG) Documentation Roadmaps
Content Filtering Support Overview
Category-based Content Filtering Support ▀
Cisco ASR 5000 Series Product Overview ▄
OL-22938-01
How Category-based Content Filtering Works
The Content Filtering Subsystem integrated into the ACS subsystem consists of two primary elements; an onboard static
categorization database and a dynamic rating engine. The filtering service uses the Deep Packet Inspection (DPI)
capabilities of the ACS subsystem to classify and partition application or protocol specific flows into virtual sessions.
categorization database and a dynamic rating engine. The filtering service uses the Deep Packet Inspection (DPI)
capabilities of the ACS subsystem to classify and partition application or protocol specific flows into virtual sessions.
Content analyzers are used to identify various types of flows such as HTTP, MMS/WAP, and POP3 E-mail. A typical
HTTP request for a Web page, for example, invokes TCP and HTTP traffic analyzers. Any HTTP field including URLs
or URIs can be identified. When a subscriber session is bound by CSS to an ECS running content filtering service, the
URL/URI is extracted and compared against the static categorization database.
HTTP request for a Web page, for example, invokes TCP and HTTP traffic analyzers. Any HTTP field including URLs
or URIs can be identified. When a subscriber session is bound by CSS to an ECS running content filtering service, the
URL/URI is extracted and compared against the static categorization database.
The following figure and the steps describe how Category-based Content Filtering works during a subscriber call: