A Maintenance Domain (MD) is the part of a network that is controlled by a single administrator. For example, a customer can engage the services of a service provider, who, in turn, can engage the services of several operators. In this scenario, there can be one MD associated with the customer, one MD associated with the service provider, and one MD associated with each of the operators.
You assign one of the following eight levels to the MD:
0–2 (operator levels)
3–4 (provider levels)
5–7 (customer levels)
The levels separate MDs from each other and provide different areas of functionality to different devices using the network. An MD is characterized by a level and an MD name (optional).
A single MD can contain several Maintenance Associations (MA).