port providing broadband to multiple PCs. Consumers see value in these services and, as a result, cable operators are realizing incremental revenue now. In addition, forward-looking services, such as medical monitoring, energy management, and networked personal video recording (PVR) distribution, will be increasingly visible. (HANs and the specifics of the CableHome specification are discussed in more detail at the end of this chapter.) The Future of Cable TV Networks The industry perspective is that within 10 to 15 years, cable networks will have evolved to a converged platform. Analog video will have ceased, and telephone will have migrated to VoIP, leaving only QAM-modulated downstream channels carry- ing MPEG transport stream packets. Some of those packets will carry video, and others will carry IP traffic, which might include voice, computer files, video, set- top box commands, or network management traffic. All upstream communications will be based on DOCSIS, including cable modem traffic, IP voice, and communi- cations from DOCSIS-enabled set-top boxes and gateways and system-monitoring devices. Encryption modules will be portable, allowing any set-top box to decrypt any transmission if properly authorized, and headend encryption will no longer be inseparable from multiplexing and modulation. VOD is cable TV's fastest-growing new service category. Aside from providing additional service revenue, VOD is an essential tool in cable's competition with satel- lite. It exploits three inherent advantages that HFC networks have over direct Chapter 12 Broadband Access Alternatives broadcast satellite networks: greater raw information capacity, a broadband two-way connection, and a customer base that can be segmented into small groups. This com- bination allows the network to dynamically create and manage bidirectional informa- tion sessions with individual customers or groups of customers, which enables not only VOD but telephony, Internet access, and multiplayer interactive gaming. The initial successes of VOD lau