Specifications

Appendix B SNMP Management Installation and Operation Manual
B-2 SNMP Environment FCD-E1LC Ver. 1.0
SNMP Operations
The SNMP protocol includes four types of operations:
getRequest Command for retrieving specific management information from
the managed entity. The managed entity responds with a
getResponse message.
getNextRequest Command for retrieving sequentially specific management
information from the managed entity. The managed entity
responds with a getResponse message.
setRequest Command for manipulating specific management information
within the managed entity. The managed entity responds with
a setResponse message.
trap Management message carrying unsolicited information on
extraordinary events (e.g., alarms) reported by the managed
entity.
The Management Information Base
The management information base (MIB) includes a collection of managed
objects
. A managed object is defined as a parameter that can be managed, such
as a performance statistics value.
The MIB includes the definitions of relevant managed objects. Various MIBs can be
defined for various management purposes, types of equipment, etc.
An object's definition includes the range of values and the “access” rights:
Read-only Object value can be read, but cannot be set.
Read-write Object value can be read or set.
Write-only Object value can be set, but cannot be read.
Not accessible Object cannot be read, nor set.
MIB Structure
The MIB has an inverted tree-like structure, with each definition of a managed
object forming one leaf, located at the end of a branch of that tree. A unique
path reaches each “leaf” in the MIB, therefore 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 (ASN.1).
Since the general collection of MIBs 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, MIBs are classified in
various classes (branches), one of them being the experimental branch, and
another the group of private (enterprise-specific) branch.
Under the private (enterprise-specific) branch of MIBs, each enterprise
(manufacturer) can be assigned a number, which is its enterprise number.