SNMP Terms (Windows Embedded CE 6.0)
1/6/2010
- Instance
An Instance specifies in which row an object that is part of a table is located. The instance is appended to the Object Identifier and has a similar format as the former. For objects that are not part of a table the instance is Zero.
- Managed Node
A managed node is a network device that is being monitored actively by an agent. Each managed node is a member of one or more management communities. Each community is identified by a community name or community string, which is encapsulated in the SNMP message.
- Messages
In an SNMP operation, network information is exchanged through messages or Protocol Data Units (PDUs). Each SNMP operation has its own type of message. Management systems use messages to request that an operation be performed on the managed variable that is maintained by an SNMP agent. SNMPv1 defines three types of request messages: GetRequest, GetNextRequest, and SetRequest. SNMPv2 defines an additional type of request message: GetBulk. The SNMP agent responds to a received request by sending a GetResponse message. If a predefined condition or an extraordinary event occurs, the SNMP agent sends a Trap message to the network management system.
- MIB
A Management Information Base (MIB) is a schema or blueprint that contains the hierarchical order of all of the managed objects. Each managed object in a MIB has a unique identifier. The identifier includes the object's type (such as counter, string, gauge, or address), access level (such as read/write), size restrictions, and range information.
- MIB Compiler
A MIB compiler is a program that translates MIBs written in ASN.1 into another data format, such as C (which is later compiled as part of the agent) or a relational database. Most management systems and agents cannot read ASN.1 MIBs and must first compile them into a more readable format.
- MIB Module
A MIB module is a readable, ASN.1 description of SNMP MIB objects, data definitions, conventions, subtypes and events. Because MIB modules are usually compiled into another format before they are used, they can be considered to be the source code of the MIB.
- NMS
A Network Management Station (NMS) is a console that monitors and controls network elements by executing management applications. To perform NMS functions, high-performance workstation computers with a fast CPU and extensive disk space are used. A managed network requires at least one NMS workstation to perform SNMP operations.
- OID
An Object Identifier (OID) is the identification value of an object that is defined in a MIB. OIDs are arranged in a hierarchical tree structure compliant with Internet standard, that consists of roots and branches. An OID is written as a sequence of subidentifiers, starting with the tree root in dotted decimal notation. For example, the Microsoft branch of the MIB naming tree is expressed as 1.3.6.1.4.1.311.
- SNMP Agent
An SNMP Agent is an application that performs the operational role to receive requests, process them, send responses to the manager, and send traps when an event occurs.
- SNMP Manager
An SNMP Manager or SNMP Service is an application that performs the operational role of generating requests to modify and retrieve management information, and of receiving the requested information and trap event reports that are generated by the SNMP agent.