SID uses extensively the concepts of “Specification” and “Instance”. The Specification provides the definition of the concept, whether it be a Product Offering, Resource or even Customer Facing Service (CFS), whilst the Instance allows as the name indicates allows individual instances of the specification be identified and linked, where appropriate to a particular Customer Account.
The Specification is easy to understand if you think of your car; every component in the car has a part number. The part number for, say the silencer (muffler), is the same for every car of the same year, model and manufacturer as your car. This allows you to go to the car parts shop and buy a new one. The silencer you buy will also have a serial number on it which is unique to that particular silencer, no other silencer with that part number will have the same serial number. So the part number identifies the Specification and the serial number identifies the Instance.
It is fairly easy to see how this model extends to customer equipment like a SIM card or handset. For example, each handset has a unique serial number (in the case of GSM handsets, the IMEI) and is identified by a part number, or name such as Motorola Raza or Nokia 6300. However this notion extends to Product Offering which is a specification of the Offering and Product Subscription which is the instance of a Customer’s use of the Product Offering and down to Installed Customer Facing Service which is the instantiation of the CFS (which is a specification too).
When defining a specification for a piece of equipment like a handset there are a set of properties that all handsets have, like
- Weight
- Talk time
- Size
- Colour
- Frequency band
as well as the capabilities of the handset, such as Bluetooth, camera, tones, MP3 player etc etc. So we can define a set of parameters relevant to the Resource Specification and then for a particular model define a set of Parameter Values (e.g. 100 grams, 4 hours, 10x5x1 cm, silver, 1800 MHz) that define the model.
We can then extend this idea to CFS where we can, for example, for “Voice Mail” (a CFS) we can define a set of parameters like
- Language
- Personalised greeting
- Message capacity
- Message latency, etc
This is a very powerful way of defining both the capabilities of services, products and hardware and recording the particular parametrisation relevant to individual customer's usage of them.
