3.1. Motivation

Let's begin by putting forth a few specific goals for residential gateway applications.

First, a gateway customer ought to have the freedom to choose a version of a service from any one of multiple competing vendors. If multiple companies are to develop services, they must program against a consistent model and API. Their services need to cooperate with, and be insulated from, one another when existing on the same gateway. For example, a chat service from America Online can use a 3Com modem service on the gateway, but it should never clash with an offering from MSN, accidentally or not.

Second, the relationship between the customer and the service provider should be flexible: The customer can subscribe to services as well as discontinue them at any time. This requires the capability of installing a service, putting it to use, and removing it later. It also requires that the service be packaged in a form that can travel easily across the network.

Third, a service must be developed with enough stability so that variations or changes of its internal implementation do not cause repercussions on other services that depend on it. For example, it is desirable to use a photo-swapping service without worrying about how the images are transferred. Depending on the hardware configuration of the box, one implementation of the service may use USB, another may use the Ethernet.

The OSGi architecture provides a programming model that satisfies these requirements.