Comcast's Web Notification System Design

The objective of this document is to describe one method of providingnotifications to web browsers that has been deployed by Comcast, alarge Internet Service Provider (ISP). Such a notification system canbe used by an ISP to provide near-immediate notifications to theirusers, such as to warn them that their traffic exhibits patterns thatare indicative of malware or virus infection, for example. There aremany proprietary systems that can perform such notifications on themarket today, some of which use inline-based Deep Packet Inspection(DPI) systems. This document describes one example of such a systemthat does not rely upon DPI systems, and is instead based in openstandards and open source systems. While the system described hereinis in some ways specific to the Data-Over- Cable Service InterfaceSpecifications (DOCSIS) networks used by most cable-based broadbandISPs, components and concepts described in this document can generallybe applied to many different types of networks.