1.2. The Service Gateway
Traditional service providers such as utilities, telephone, and cable TV companies all have their own dedicated wires into the home. However, in the envisioned networked home of the future, this configuration will soon become unmanageably complex for a diversified portfolio of services, such as home security, health monitoring, telephony, and audio/video media, each possibly using a different communication technology. It will also miss interesting opportunities for integration. As a result, a centralized device interfacing the external Internet and the internal device and appliance networks has been proposed (Figure 1.1). This device is called a service gateway.[1]
[1] This term is used interchangeably with residential gateway in this book, although it could be argued that a service gateway may operate in settings other than the residence, such as a retail outlet or an information kiosk. They refer to the same type of device in terms of what they do, however.
Figure 1.1. The role of a service gateway
A typical native platform of a service gateway consists of
A processor
Memory
Persistent storage (disk or flash RAM)
TCP/IP networking
A device network (for example, a serial or parallel port)
An operating system or real-time operating system
The familiar cable set-top box can be augmented with more “smarts” and transformed into a residential gateway. For example, Motorola's DCT-5000+ set-top is equipped with a 300+-MHz MIPS processor, 14 MB of memory, an integrated cable modem, the Ethernet, Universal Serial Bus (USB), and IEEE 1394 interfaces. Its main application is to provide traditional video services and high-speed Internet access [2].
Other companies have designed service gateways from the ground up. For example, Ericsson's e-box features a 100-MHz 486 CPU, 32 MB of memory, 24 MB of flash memory, a 10BaseT Ethernet interface, and a serial port. Its purpose is to provide e-services: Internet access, alarm and security, remote energy control and management, health care, e-commerce, and entertainment [3].
These are just a few examples of what is being tried out today. As costs decrease, more powerful devices can be expected to emerge on the market.
The residential gateway can participate in a wide range of home-based services:
Home security, fire alarm, disaster alert, and emergency response
Home-based health care, patient diagnosis, and child-care monitoring
Energy management involving heating, ventilation, and air-conditioning
The benefits of delivering services to homes are twofold. For the consumer, her demands are met exactly when and how she needs them inside her home; intermediaries are eliminated so that she can hope for cheaper products and services. For merchants and service providers, they can serve a much more focused market more efficiently and can open new revenue streams with value-added services. The residential gateway can also leverage one service to benefit another. For example, it is possible for the home theater system to send a signal to lower the automated window blinds when a movie starts on a Sunday afternoon. A gateway that can authenticate a user via a cell phone can also let the user remotely open a door when a family member forgets to bring the key.