Deployment diagrams are used to visualize the topology(拓扑）of the physical components of a system, where the software components are deployed.
Deployment diagrams consist of nodes and their relationships.

Purpose of Deployment Diagrams

构件图：关注软件自身环境 部署图：关注软件部署的硬件环境
Deployment diagrams are used for describing the hardware components, where software components are deployed.

Component diagrams and deployment diagrams are closely related.