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Gemini G3 - User Manual
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4.7.3.5.2
SNMP Overview
SNMP (Simple Network Management Protocol) is used by network management systems to manage and
monitor network-attached devices. SNMP is based on the manager/agent model consisting of a manager,
an agent, a database of management information, managed objects, and the network protocol. The man-
ager provides the interface between the human network manager and the management system. The agent
provides the interface between the manager and the physical devices being managed (Figure 28). SNMP
uses basic messages (
such as GET, GET-NEXT, SET, and TRAP
) to communicate between the manager
and the agent.
Figure 28 - SNMP: manager/agent model
MIB
The manager and agent use a Management Information Base (MIB), a logical, hierarchically organized
database of network management information. MIB comprises a complete collection of objects used to
manage entities in a network. A long numeric tag or object identifier (OID) is used to distinguish each
variable uniquely in the MIB and SNMP messages.
GeminiG3 MIB File
Each GeminiG3 unit firmware package is bundled with three MIB files (found inside mibs.zip file):
•
dataradio-regs.mib
: contains a top level set of managed object definitions aimed at managing Datara-
dio products.
•
1213.mib
: contains a set of managed object definitions aimed at managing TCP/IP-based internets.
•
gcu3.mib
: contains a set of managed object definitions aimed at managing Dataradio mobile units.
OID
In SNMP, each object has a unique OID consisting of numbers separated by decimal points. These object
identifiers naturally form a tree. Figure 29 illustrates this tree-like structure for
1213.mib,
which comes
bundled with every ParagonP3 unit package
.
A path to any object can be easily traced starting from the
root (top of the tree). For example, object titled “SNMP” has a unique OID: 1.3.6.1.2.1.11. The MIB as-
sociates each OID with a label (e.g. “SNMP”) and various other parameters. When an SNMP manager
wants to obtain information on an object, it will assemble a specific message (e.g. GET packet) that in-
cludes the OID of the object of interest. If the OID is found, a response packet is assembled and sent
back. If the OID is not found, a special error response is sent that identifies the unmanaged object.
MANAGER
AGENT
Management Database
Management Database
Managed Object
Messages
Network
Protocol
Management System
Managed Element
Human Network
Manager