well thought out approach to a select service area. But perhaps the most comprehensive working architecture from a single vendor is the Microsoft Connect Service Framework in its largest context. Among service providers, we are impressed with AT&T’s architecture and with Swisscomm Mobile.

SDF differs from SDPs in some important but subtle ways. One way of looking at SDF is as a super-framework that allows many different SDPs to be linked together. Indeed, with some architectural constraints, even heritage systems may be used in service composition, abstracted thru a SOA interface. Importantly, SDF’s will incorporate the architectural notion of domains with different resources, policies, and security. This enables not just the assembly of a service that spans multiple platforms supplied by multiple vendors – it enables the composition of services that cross operator boundaries using networks, resources, and application components from multiple service providers. This extends the notion of wholesaling from circuits to service components.

Lastly, and quite powerful in an SDF “Any application rendering a service may in turn become a component.” (TR139) The SDF should not only provide the fast and reliable assembly of the service components but also provide the fast and reliable reassembly of any service component in another assembly. This recursive principle brings SDF right to the starting edge of the principles of Autonomic Communication.

Technical issues aside, a simpler way of looking at the difference between SDPs and SDF:

• SDPs allow creation of services.
• SDF allows services to be mashed up: service calling service, calling service.

For instance, an address book lookup gives a name which is used to find a person’s location which brings up a map of reasonable trip routing, resulting in a call, once connected, linking in web co-browsing, with a location, type search to find for a restaurant along the trip route, clicking the restaurant’s advertisement, resulting in a reservation, and a message to social-network shared friends to met them with directions inserted from that person’s location. This Mashup is becoming possible with some Over-the-Top (OTT) service platforms; network operating providers must meet this challenge.

What we propose is that a fully realized SDF could enable creation of a middle-ground strategy between the wild west OTT services and the existing “walled garden” approaches typical of network operators. We call this open, yet controlled, strategy the “garden club.” Many different players in the ecosystem contribute both to the resources