What is the difference between N-layer and N-tier architecture?

Answer»

N-Layer	N-Tier
All the layers may reside on the same physical COMPUTERS(server) while the components in different layers communicate via well-defined interfaces.	In this type of architecture, there are at least THREE separate logical PARTS, each LOCATED on a different physical server.
Communication between layers is explicit and loosely coupled.	In this, communication between the tiers is asynchronous to support scalability.

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