Unit installation

Appendix B SNMP Management Installation and Operation Manual
B-2 SNMP Environment FCD-E1
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 getResponse
message.
trap Management message carrying unsolicited information on extraordinary
events (that is, events which occurred not in response to a management
operation) 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 (also called “instances”) and the
“access” rights:
Read-only Instances of that object can be read, but cannot be set.
Read-write Instances of that object can be read or set.
Write-only Instances of that object can be set, but cannot be read.
Not accessible Instances of that 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.