Control plane: All requests for control plane operations are sent to the Azure Resource Manager URL. That URL varies by the Azure environment.
And from image here, it seems that the control plane and Azure Resource Manager are the same things. What are the differences between them?
Azure Resource Manger (ARM) is one of two Deployment models in Azure, the other is Azure Service Manager (ASM), now called Classic. These models are considered the Control plane. You can learn more about the different models here:
https://docs.microsoft.com/en-us/azure/azure-resource-manager/management/deployment-models
Azure operations can be divided into two categories - control plane and data plane. You use the control plane to manage resources in your subscription. You use the data plane to use capabilities exposed by your instance of a resource type.
Thanks Ken W MSFT, Here is the answer from Azure Docs.
What is Azure Service Manager and what does it mean by classic?
The word "classic" in IaaS VM (classic) refers to VMs managed by Azure Service Manager (ASM). Azure Service Manager (ASM) is the old control plane of Azure responsible for creating, managing, deleting VMs and performing other control plane operations.
What is Azure Resource Manager?
Azure Resource Manager is the latest control plane of Azure responsible for creating, managing, deleting VMs and performing other control plane operations.
