PDN Gateway Overview
Features and Functionality - Inline Service Support ▀
Cisco ASR 5x00 Packet Data Network Gateway Administration Guide ▄
71
Content Filtering policy enforcement is the process of deciding if a subscriber should be able to receive some content.
Typical options are to allow, block, or replace/redirect the content based on the rating of the content and the policy
defined for that content and subscriber. The policy definition is transferred in an authentication response from a AAA
server or Diameter policy message via the Gx reference interface from an adjunct PCRF. The policy is applied to
subscribers through rulebase or APN/Subscriber configuration. The policy determines the action to be taken on the
content request on the basis of its category. A maximum of one policy can be associated with a rulebase.
ICAP Interface
Provides a value-added service to prevent unintended viewing of objectionable content that exploits underage children.
Content Filtering offers mobile operators a way to increase data ARPU and subscriber retention through a network-
based solution for parental controls and content filtering. The Content Filtering ICAP solution is appropriate for
operators with existing installations of Active Content Filtering servers in their networks.
The Enhanced Charging Service (ECS) for the P-GW provides a streamlined Internet Content Adaptation Protocol
(ICAP) interface to leverage the Deep Packet Inspection (DPI) to enable external Application Servers to provide their
services without performing the DPI functionality and without being inserted in the data flow. The ICAP interface may
be attractive to mobile operators that prefer to use an external Active Content Filtering (ACF) Platform. If a subscriber
initiates a WAP (WAP1.x or WAP2.0) or Web session, the subsequent GET/POST request is detected by the deep
packet inspection function. The URL of the GET/POST request is extracted by the local DPI engine on the ASR 5x00
platform and passed, along with subscriber identification information and the subscriber request, in an ICAP message to
the Application Server (AS). The AS checks the URL on the basis of its category and other classifications like, type,
access level, content category and decides if the request should be authorized, blocked or redirected by answering the
GET/POST message. Depending upon the response received from the ACF server, the P-GW either passes the request
unmodified or discards the message and responds to the subscriber with the appropriate redirection or block message.
Header Enrichment: Header Insertion and Encryption
Header enrichment provides a value-added capability for mobile operators to monetize subscriber intelligence to include
subscriber-specific information in the HTTP requests to application servers.
Extension header fields (x-header) are the fields that can be added to headers of a protocol for a specific purpose. The
enriched header allows additional entity-header fields to be defined without changing the protocol, but these fields
cannot be assumed to be recognizable by the recipient. Unrecognized fields should be ignored by the recipient and must
be forwarded by transparent proxies.
Extension headers can be supported in HTTP/WSP GET and POST request packets. The Enhanced Charging Service
(ECS) for the P-GW offers APN-based configuration and rules to insert x-headers in HTTP/WSP GET and POST
request packets. The charging action associated with the rules will contain the list of x-headers to be inserted in the
packets. Protocols supported are HTTP, WAP 1.0 and WAP 2.0 GET, and POST messages.
Important:
For more information on ECS, see the
Enhanced Charging Service Administration Guide
.
The data passed in the inserted HTTP header attributes is used by end application servers (also known as Upsell
Servers) to identify subscribers and session information. These servers provide information customized to that specific
subscriber.
The Cisco P-GW can include the following information in the http header:
User-customizable, arbitrary text string
Subscriber‘s MSISDN (the RADIUS calling-station-id, in clear text)
