Historically, Azure services were provided via one portal prior to 2014, the classic portal, which can be accessed via the following URL https://manage.windowsazure.com/.
The model that was used for that portal is called the ASM model, within which each resource existed independently. You could not manage your resources together; you had to build up and track each resource. For example, you would have to manage storage from the storage blade, and the same goes for the virtual networks, VMs, and so on. So, when your environment got bigger, there would be chaos in the management scheme. You would have to know which VMs were stored in which storage account, and that could lead to some critical situations, such ...
