8.1 Introduction

HAVi is a digital audio video networking initiative that provides a home networking software specification for seamless interpretability among home entertainment products. Equally important, the HAVi specification is device-centric, so it has been designed to meet the particular demands of digital audio and video. It defines an operating-system-neutral middleware that manages multi-directional audio video streams, event schedules, and registries, while providing APIs for the creation of a new generation of software applications. Whatever their brand, the focus is on the control and content of digital audio video streams. HAVi software takes advantage of the powerful resources of chips built into modern audio and video appliances to give you the management function of a dedicated audio-video networking system.

The HAVi architecture is intended for implementation on Consumer Electronics (CE) devices and computing devices such as tuners, VCRs, clocks, cameras , DVD, and other audio video players, displays, amplifiers , modems, and Web proxies. As such, it provides a set of services that facilitate interpretability and the development of distributed applications on home networks. HAVi is intended for, but not restricted to, electronic devices supporting the IEEE 1394 [1394] and IEC 61883 [DAV] interface standards. Four pillars guided the development of HAVi:

1. Interpretability : Functions on a device within the HAVi networking system may be controlled from another device within the system. Search for an available VCR to record a TV program, e.g., with commands being given via the menu selection of another TV display.

2. Brand independence : Entertainment products from different manufacturers communicate with each other when connected into a HAVi network. Imagine a variety of VCRs, hi-fis, DVD players, MiniDisc machines, active loudspeakers, and set-top boxes, all daisy-chained together and showing up on the TV for you to control from your one remote.

3. Hot plug and enjoy : HAVi compliant devices automatically announce their presence and capabilities to every other device on the HAVi network, greatly simplifying installation and setup. Just plug and enjoy. There would be no more complicated and difficult installation instructions and no configuration of network addresses or device drivers.

4. Link the past, upgradeable in the future : Today's i.LINK-enabled camcorders and other devices may be controlled on a HAVi network for basic functions. HAVi compliant devices may come with their own dynamic device control modules. Updating functionality can be done by downloading new capabilities via the Internet. Also, additional or replacement products can simply be incorporated into the network.

A key goal of the HAVi architecture was to be future-proof. Therefore, interpretability was critical. HAVi is a software architecture that allows new devices to be integrated into the home network and to offer their services in an open and seamless manner. The HAVi architecture provides:

• A set of software elements along with the protocols and APIs needed to achieve interpretability device abstraction and device control models, an addressing scheme, and lookup service for devices and their resources

• An open execution environment supporting visual presentation and control of devices, and providing run-time support for third party applications communication mechanisms for extending the environment dynamically through plug-and-play capabilities,

• A versioning mechanism that preserves interpretability as the architecture evolves, management of isochronous data streams.