Snmp Mib Objects - AudioCodes Mediant 1000 User Manual

can be determined via SNMP without the overhead associated with logging into the
device, or establishing a TCP connection with the device.
Get Next Request - Enables the SNMP standard network managers to "walk" through
all SNMP values of a device (via the "get-next" request) to determine all names and
values that a device supports. This is accomplished by beginning with the first SNMP
object to be fetched, fetching the next name with a "get-next", and repeating this
operation.
Set Request - The SNMP standard provides a action method for a device (via the "set"
request) to accomplish activities such as disabling interfaces, disconnecting users,
clearing registers, etc. This provides a way of configuring and controlling network
devices via SNMP.
Trap Message - The SNMP standard furnishes a mechanism for a device to "reach
out" to a network manager on their own (via the "trap" message) to notify or alert the
manager of a problem with the device. This typically requires each device on the
network to be configured to issue SNMP traps to one or more network devices that are
awaiting these traps.
The above message types are all encoded into messages referred to as "Protocol Data
Units" (PDUs) that are interchanged between SNMP devices.
8.1.1.2

SNMP MIB Objects

The SNMP MIB is arranged in a tree-structure, similar to a disk directory structure of files.
The top level SNMP branch begins with the ISO "internet" directory, which contains four
main branches:
The "mgmt" SNMP branch - Contains the standard SNMP objects usually supported
(at least in part) by all network devices.
The "private" SNMP branch - Contains those "extended" SNMP objects defined by
network equipment vendors.
The "experimental" and "directory" SNMP branches - Also defined within the "internet"
root directory, are usually devoid of any meaningful data or objects.
The "tree" structure described above is an integral part of the SNMP standard, though the
most pertinent parts of the tree are the "leaf" objects of the tree that provide actual
management data regarding the device. Generally, SNMP leaf objects can be partitioned
into two similar but slightly different types that reflect the organization of the tree structure:
Discrete MIB Objects - Contain one precise piece of management data. These objects
are often distinguished from "Table" items (below) by adding a ".0" (dot-zero)
extension to their names. The operator must merely know the name of the object and
no other information.
Table MIB Objects - Contain multiple pieces of management data. These objects are
distinguished from "Discrete" items (above) by requiring a "." (dot) extension to their
names that uniquely distinguishes the particular value being referenced. The "." (dot)
extension is the "instance" number of an SNMP object. For "Discrete" objects, this
instance number is zero. For "Table" objects, this instance number is the index into
the SNMP table. SNMP tables are special types of SNMP objects, which allow parallel
arrays of information to be supported. Tables are distinguished from scalar objects,
such that tables can grow without bounds. For example, SNMP defines the "ifDescr"
object (as a standard SNMP object) that indicates the text description of each
interface supported by a particular device. Since network devices can be configured
with more than one interface, this object can only be represented as an array.
By convention, SNMP objects are always grouped in an "Entry" directory, within an object
with a "Table" suffix. (The "ifDescr" object described above resides in the "ifEntry" directory
contained in the "ifTable" directory).
User's Manual 118
Digital Mediant 1000
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