20. Communication Requirements

Many products have a requirement to communicate with the external world via a variety of communications networks. These requirements emanate either directly from their function as a communications apparatus or as a result of their peripheral market requirements such as alarm reporting and fast response maintenance.

Communication Applications

The product definition should highlight the particular communications applications that the product is to enable or make use of. Generally these applications will be of the following types:

• command and control requirements in which the product actively commands and controls remote resources closely associated with it;
• user communications requirements in which case the product facilitates the transfer of information between the user and other external parties;
• problem reporting requirements, in which case the product may act as a subservient element of some other entity,
• or as a peer in a resilient system supporting redundancy for the purposes of ensuring system integrity.

Whatever the communications applications requirements, it is worthwhile considering the information that needs to be conveyed to the product designers in order for them to properly assess the network connection methods and protocols needed by the product. The International Standards Organisation has developed an abstract architecture for defining communications protocols and requirements.

Aspects of this ISO Open Systems Interconnection model are useful for identifying what considerations the product definition should encompass when prescribing communications requirements.