1394 Communications Media Manager (CMM) - interfaces with IEEE1394 to provide services to other HAVi software elements or application programs which reside in the same appliance as the CMM.

The CMM provides two types of services: (1) it provides a transport mechanism for sending requests to and receiving indications from remote devices, and (2) it abstracts the bus activities and presents the resulting information to the HAVi system.

Event Manager (EM) - a service that enables software elements to post a record of specific events (such as changes in the network configuration) and subscribe to reports of such records. The Event Manager is responsible for delivering reports of each posted event to all of the elements subscribing to it.

Specifically, when appliances are added to or removed from the network, the EM reports these changes to each appliance on the network. This allows for the convenience of "hot" plug-and-play connectivity.

Registry - records the attributes of the software elements of all appliances on the network. By checking the registry, an appliance can locate and recognize the essential software elements of other devices on the network. This makes it possible for the different appliances to interoperate.

Messaging System (MS) - is responsible for transferring messages between software elements in a location transparent way. ( i.e. the sender and receiver are not aware of which appliance in the network they are located.)

Device Control Module (DCM) - offers a model of a device on the network. Applications interact directly with a DCM, not the device itself. The DCM offers a proper API, and shields applications from idiosyncrasies of the individual devices. This enables each appliance on the network to recognize the functions of the other devices on the network, and it enables these functions to be controlled from a remote location.

DCM Manager - controls the installation of DCMs for various devices in the network. It automatically reacts to changes in the network by installing new DCMs for new devices. It allows for continuous appliance operation even during network reconfigurations, and it accepts user-preferred settings for DCM installation.

Data Driven Interaction (DDI) Controller - renders a GUI (Graphical User Interface) on a appliance's display based on the GUI data provided by a HAVi software element such as a DCM. The GUI data contains sufficient information to produce a GUI on a wide range of displays, varying from graphical to text-only. The DDI supports user interaction with the appliance.

Stream Manager (SMGR) - provides a service for establishing end-to-end real-time AV stream connections. Connections may be between two or more appliances. The Stream Manager is responsible for the configuration of both internal (within a device) and external (between devices) connections. It also requests and releases network resources and provides global connection information, and it supports reconnection after the network resets.