A deployment diagram is a diagram that shows the configuration of run time processing nodes and the components (hardware, software & middleware on hardware) that live on them that is used to model the static deployment view of a system (topology of the hardware).
Graphically, a deployment diagram is a collection of vertices and arcs. Deployment diagrams commonly contain Nodes and Dependency & association relationships. It may also contain notes and constraints.
Firstly, identify the nodes that represent your system's client and server processors and then highlight those devices that are relevant to the behavior of your system.
For example, you'll want to model special devices, such as credit card readers, badge readers, and display devices other than monitors, because their placement in the system's hardware topology are likely to be architecturally significant. � Provide visual cues for these processors and devices via stereotyping. � Model the topology of these nodes in a deployment diagram. Similarly, specify the relationship between the components in your system's implementation view and the nodes in your system's deployment view.
A node usually represents a piece of hardware in the system. A connection depicts the communication path used by the hardware to communicate usually indicates the method i.e. TCP/IP
Visual Paradigm supports deployment diagram and other UML diagram types. You can find all the tools you need in modeling deployment views and other aspects of software systems.