Interface View

Closely related to the logical view is the interface view. Interfaces are one of the riskiest parts of any software system, so it’s very useful to show what the internal/external interfaces are and how they work.

• Are the key internal (e.g. databases, messaging systems, etc) and external interfaces (e.g. other systems) well specified at a high level?
• If messaging is being used, which queues (point-to-point) and topics (pub-sub) are components using to communicate?
• What format are the messages (e.g. plain text or XML defined by a DTD/Schema)?
• Are they synchronous or asynchronous?
• Are asynchronous messaging links guaranteed?
• Are subscribers durable where necessary?
• Can messages be received out of order and is this a problem?
• Who has ownership of the interfaces?
• Are interfaces idempotent?
• How often does the interface change and how is versioning handled?
• Is the interface always available or do you (e.g.) need to cache data locally?