An enterprise composite model includes :
How we can build a Management Block for all the enterprise?
Can we have one management VLAN for all enterprise?
If the answer is yes, as far as connection between different blocks is layer 3, so how one VLAN can spread in all network?
Yes, if you have multiple management VLANs - as we do - you need to have a layer 3 switch or a router to route between the different management VLANs. This is especially true if if you have your management servers (e.g. Cisco Works LMS, etc) on the one of the management VLANs and they need to be able to reach all of the devices to be able to monitor them.
We use the same infrastructure for management and user access but you could in theory create a completely separate management network with one or more separate layer 3 switches to do the routing and dedicated links between them.