CTC Union FRM220-NMC, Руководство пользователя

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Appendix A
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A.2.19.4 MIB Structure
The MIB has an inverted tree-like structure (root over leaves), with each definition of a managed instance
forming one leaf, located at the end of a branch of that tree. Each "leaf" in the MIB is reached by a unique path. By
numbering the branching points, starting with the top, each leaf can be uniquely defined by a sequence of numbers.
The formal description of the managed objects and the MIB structure is provided in a special standardized format,
called Abstract Syntax Notation 1, or
ASN.1 (pronounced A-S-N dot one).
Since the general collection of MIB's can also be organized in a similar structure, under the supervision of the
Internet Activities Board (IAB), any parameter included in a MIB that is recognized by the IAB is uniquely defined.
To provide the flexibility necessary in a global structure, MIB's are classified in various classes (branches), one
of them being the experimental branch, another being the management (mgmt) branch, and yet another the group
of private (enterprise-specific) branches. Under the private enterprise-specific branch of MIB's, each enterprise
(manufacturer) can be assigned a number, which is its enterprise number. The assigned number designates the
top of an enterprise-specific sub-tree of non-standard MIB's.
Enterprise-specific MIB's are published and distributed by their creators, who are responsible for their contents.
The MIB supported by the FRM220-1000EAS SNMP Agent follows RFC 1213 (MIB-2 standard).
A.2.19.5 SNMP Communities
To enable the delimitation of management domains, SNMP uses "communities". Each community is identified
by a name, which is an alphanumeric string of up to 255 characters defined by the user. Any SNMP entity (this term
includes both managed nodes and management stations) is assigned by its user a community name. In parallel,
the user defines for each SNMP entity a list of the communities which are authorized to communicate with it, and
the access rights associated with each community (this is the SNMP community name table of the entity).
In general, SNMP agents support two types of access rights:
Read-only
the SNMP agent accepts and processes only SNMP getRequest
and getNextRequest commands from management stations
which have a read-only community name.
Read-write
the SNMP agent accepts and processes all the SNMP
commands received from a management station with a read-write
community name. SNMP agents are usually configured to send traps to
management stations having read-write communities.