d control systems On-deck = Access server Billing services mediation Subscriber = Router PTS 22050 portals 4Gbps inspection 500K subscribers Small POP Aggregation Internet network large POP PTS 24000 (virtual switch cluster) PTS 22400 Wireless 480Gbps intersection 20Gbps inspection 2M subscribers "On-deck services" are those that the carrier or ISP offers directly such as video-on-demand and self-service portals. "Control systems" are applications such as billing and charging used to bill customers and manage networks. Deep packet switches typically interface with on-deck services and control systems. Figure 1-4 Access devices such as Digital Subscriber Line Access Multiplexers (DSLAMs) connect to customers' modems. The POP (Point of Presence) is the loca- tion of the ISP's switching equipment. Managed services include e-mail, text messag- ing, and content from CNN. (Courtesy Sandvine, Inc.) Using DPI to Manage Networks in Private and Public Educational Institutions In addition to ISPs, universities, colleges, and high schools also use DPI to manage traffic. Large universities often transmit cable TV to dorm rooms and classrooms over the same fiber networks used for all of their data and voice traffic. Educational insti- tutions often carry IP video downloaded from the Internet to classrooms. The DPI software prioritizes video transmitted over these internal networks. Prioritizing video ensures that the video is of acceptable quality. If it's not prioritized, packets might be dropped when the school's network is congested, causing images to freeze. In other cases, universities and ISPs have been served warrants from law enforce- ment agencies asking that they turn over the names of students or others who download music illegally from music sharing sites or peer-to-peer Internet sites. These agencies Computing and Enabling Technologies can use DPI services to identify these individuals. In 2009, several music companies sued a 25-year-old graduate student for illegal music downloads and won a $670,000 judgment. In 