At the center of the Value Chain sits the Reference Architecture, underpinning and tying together the Value Streams. This diagram shows the first level of the IT4IT Reference Architecture. On first appearance it looks rather linear, but this is not the case. It actually reveals a continuous flow, with feedback running all the way through it. The blue boxes are the Functional Components, which act upon the Key Data Objects (the black circles). Notice that the Key Data Objects are tied together with solid lines. These lines represent the Relationships between Objects. The purple circles represent a special designation of Data Object, the Service Backbone Data Object. These are characterized by physical objects in the Service Model.
Finally, strip off the Functional Components and you have a great view of the Relationships between all of the Key Data Objects, and how you can trace them from the beginning to the end, and from the end to the beginning by referring to the Service Backbone Data Objects.