Digisol DG-FS4526E, Руководство по управлению

Страница: 1030 / 1162

C
HAPTER
40 | CFM Commands
– 1030 –
pass, and only if a maintenance end point (MEP) is created at
some lower MA Level.
none – No MIP can be created for any MA configured in this
domain.
D
EFAULT
S
ETTING
No maintenance domains are configured.
No MIPs are created for any MA in the specified domain.
C
OMMAND
M
ODE
Global Configuration
C
OMMAND
U
SAGE
A domain can only be configured with one name.
Where domains are nested, an upper-level hierarchical domain must
have a higher maintenance level than the ones it encompasses. The
higher to lower level domain types commonly include entities such as
customer, service provider, and operator.
More than one domain can be configured at the same maintenance
level, but a single domain can only be configured with one maintenance
level.
If MEPs or MAs are configured for a domain using the ethernet cfm mep
command or ma index name vlan command, they must first be
removed before you can remove the domain.
Maintenance domains are designed to provide a transparent method of
verifying and resolving connectivity problems for end-to-end
connections. By default, these connections run between the domain
service access points (DSAPs) within each MA defined for a domain,
and are manually configured using the ethernet cfm mep command.
In contrast, MIPs are interconnection points that make up all possible
paths between the DSAPs within an MA. MIPs are automatically
generated by the CFM protocol when the mip-creation option in this
command is set to “default” or “explicit,” and the MIP creation state
machine is invoked (as defined in IEEE 802.1ag). The default option
allows MIPs to be created for all interconnection points within an MA,
regardless of the domain’s level in the maintenance hierarchy (e.g.,
customer, provider, or operator). While the explicit option only
generates MIPs within an MA if its associated domain is not at the
bottom of the maintenance hierarchy. This option is used to hide the
structure of network at the lowest domain level.
The diagnostic functions provided by CFM can be used to detect
connectivity failures between any pair of MEPs in an MA. Using MIPs
allows these failures to be isolated to smaller segments of the network.
Allowing the CFM to generate MIPs exposes more of the network
structure to users at higher domain levels, but can speed up the
process of fault detection and recovery. This trade-off should be
carefully considered when designing a CFM maintenance structure.