This topic describes the basic concepts about DDH.
DDH related terminology is as follows.
|Dedicated Host||Abbreviated to DDH, a physical server that you can exercise full control over the resources. It enables physical isolation on physical server level for tenants. For more information, see what is a dedicated host.|
|Tenant||An Alibaba Cloud account, which may own multiple RAM users, has full control over the resources of a Dedicated Host. For RAM user, see what is RAM.|
|Dedicated Host Type||The configurations of a Dedicated Host, including the physical cores, sockets, local disks, virtual CPU (vCPU) cores, and memory. Dedicated Host types are defined according to business scenarios. For more information, see dedicated host types.|
|Region||The physical location of the data center where physical servers are located. For more information, see regions and zones.|
|Elastic Compute Service (ECS)||A basic cloud compute service provided by Alibaba Cloud. For more information, see what is ECS.|
|ECS instance||A cloud server on shared cloud hosting or a Dedicated Host. It is virtual computing environment, working as a virtual machine. It is comprised of essential computing components, including CPU, memory, operating system, networking, and storage. For more information, see what are ECS instances.|
|ECS console||The Web application for managing ECS and DDH.|