Web Management Guide-R05

Chapter 13 | Basic Administration Protocols
Connectivity Fault Management
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The following figure shows a single Maintenance Domain, with DSAPs located on
the domain boundary, and Internal Service Access Points (ISAPs) inside the domain
through which frames may pass between the DSAPs.
Figure 298: Single CFM Maintenance Domain
The figure below shows four maintenance associations contained within a
hierarchical structure of maintenance domains. At the innermost level, there are
two operator domains which include access points marked “O
1
” and “O
2
”
respectively. The users of these domains can see their respective MEPs as well as all
the MIPs within their domains. There is a service provider domain at the second
level in the hierarchy. From the service provider’s view, the access points marked
“P” are visible, and all access points within the operator domains have also been
made visible as MIPs according to common practice. And finally, there is a customer
domain at the top of the hierarchy. Users at this level can only see the access points
marked “C” on the outer domain boundary. Again, normal practice is to hide the
internal structure of the network from outsiders to reduce security risks.
Figure 299: Multiple CFM Maintenance Domains
Note that the Service Instances within each domain shown above are based on a
unique maintenance association for the specific users, distinguished by the domain
name, maintenance level, maintenance association’s name, and assigned VLAN.
Maintenance Domain
Bridge
DSAP
ISAP
Customer MA
Provider MA
Operator 1 MA Operator 2 MA
C
C
C
C
O
1
O
1
P
O
2
O
2
P
P
O
1
O
2
P