Maintenance Domains
A maintenance domain is a management space for the purpose of managing and administering a network. A
domain is owned and operated by a single entity and defined by the set of ports internal to it and at its boundary.
The figure below illustrates a typical maintenance domain.
Figure 8: A Typical Maintenance Domain
A unique maintenance level in the range of 0 to 7 is assigned to each domain by a network administrator.
Levels and domain names are useful for defining the hierarchical relationship among domains. The hierarchical
relationship of domains parallels that of customer, service provider, and operator. The larger the domain, the
higher the level value. For example, a customer domain would be larger than an operator domain. The customer
domain may have a maintenance level of 7 and the operator domain may have a maintenance level of 0.
Typically, operators would have the smallest domains and customers the largest domains, with service provider
domains between them in size. All levels of the hierarchy must operate together.
Domains should not intersect because intersecting would mean management by more than one entity, which
is not allowed. Domains may nest or touch but when two domains nest, the outer domain must have a higher
maintenance level than the domain nested within it. Nesting maintenance domains is useful in the business
model where a service provider contracts with one or more operators to provide Ethernet service to a customer.
Each operator would have its own maintenance domain and the service provider would define its domain--a
superset of the operator domains. Furthermore, the customer has its own end-to-end domain, which is in turn
a superset of the service provider domain. Maintenance levels of various nesting domains should be
communicated among the administering organizations. For example, one management approach would be to
have the service provider assign maintenance levels to operators.
Ethernet CFM exchanges messages and performs operations on a per-domain basis. For example, running
CFM at the operator level does not allow discovery of the network by the higher provider and customer levels.
Network designers determine domain configurations.
The following characteristics of domains are supported:
•
Name is a maximum of 63 characters in length.
•
Direction is specified when the MA is configured.
Carrier Ethernet Configuration Guide (Cisco ASR 920 Series)
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Configuring Ethernet CFM
Maintenance Domains
