Appendix C SNMP Management
MX-2100/2104
Installation and Operation Manual
C-2
SNMP Environment
•
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 value 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. Each leaf in
the MIB is reached by a unique path, 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 into
various branches, one of them being the experimental branch, and another, the
private (enterprise-specific) branch. Under the private branch of MIBs, each
enterprise (manufacturer) can be assigned a number. The assigned number
designates the top of an enterprise-specific sub-tree of non-standard MIBs.
MIBs of general interest are published by the IAB in the form of a Request for
Comment (RFC) document. In addition, MIBs are also often assigned informal
names that reflect their primary purpose. Enterprise-specific MIBs are published
and distributed by their originator, who is responsible for their contents.
