Primary snmp mib operations

When learning the SNMP protocol, you should find something. The use of Linux SNMP is a key point. This also includes the use of snmp mib. So let's introduce it to you today.

Simple Network Management Protocol (SNMP) is a Simple Network Management Protocol. It provides a framework for the Network Management system to manage the underlying Network. The SNMP protocol is widely used in many types of network devices, software, and systems, mainly because it has the following features:

First, SNMP is easy to implement compared with other types of network management systems or management protocols. SNMP management protocols, snmp mib, and other related system frameworks can run on different types of devices, from low-end PCs to high-end hosts, servers, routers, switches, and other network devices.

Linux SNMP is a series of protocol groups and specifications that provide a method to collect Network Management Information from devices on the network. Linux SNMP also provides a way for devices to report problems and errors to network management workstations.

An SNMP Management Proxy component does not require a large amount of memory space during runtime, so it does not require too much computing power. The SNMP protocol can be developed quickly in the target system, so it is easy to appear in new products or upgraded old products. Although the SNMP Protocol lacks some advantages of other network management protocols, it is simple in design, flexible in expansion, and easy to use. These features greatly make up for other shortcomings in the SNMP Protocol application.
 
Secondly, the SNMP protocol is an open free product. Only organizations under IAB approved by the IETF standard agenda can modify the SNMP protocol. Vendors can also modify the SNMP protocol in private, but such results may not be worth the candle, because they have to persuade other vendors and users to support their non-standard improvement on the SNMP protocol, this is contrary to their original intention.
 
Third, the SNMP protocol has a lot of detailed documents, such as RFC, and other articles and instructions). The network industry also has a deep understanding of this Protocol, these are the foundation for the development and improvement of the SNMP protocol.
 
Finally, the SNMP protocol can be used to control various devices. For example, non-traditional devices such as telephone systems, environmental control devices, and other devices that can access the network and need to be controlled can use the SNMP protocol.

Snmp mib Tree Structure

We understand the SNMP implementation method. To provide the ability to traverse the Management Information Library, the snmp mib uses the tree naming method to name each SNMP management object instance. The name of each object instance is composed of an object class name and a suffix. The names of SNMP object classes are not repeated, so there is little danger of duplicate names between object instances of different object classes.

The SNMP application entity operates on the management objects in the Internet management information library. A subset of Management SNMP objects that an SNMP application entity can operate on is called the snmp mib authorization range. The SNMP application entity still has further access control restrictions on access to management objects within the authorization scope, such as read-only and read/write.

In the definition of a community, it is generally necessary to specify the scope of SNMP management objects authorized by the community, and correspondingly specify which SNMP object instances are the "jurisdiction" of the Community. Accordingly, the definition of a community can be imagined as a multi-Cross Tree, providing a means to traverse all SNMP management object instances in alphabetical order. With this method, SNMP can use the get-next operator to sequentially locate the next object from an object.

Most management information in SNMP exists in tables. A table corresponds to an SNMP object class, and each element corresponds to an SNMP object instance of this class. In this case, you can use the get-next method or the get/set method described later for operations on a single element (object instance) in the SNMP object in the management information table. The following describes the overall operations of a row in the table.
 
(1) Add a row: you can add a row in a table using only one set operation through SNMP. Each variable in the Operation corresponds to a column element in the row to be added, including the SNMP object instance identifier. If a table contains eight columns, the set operation must provide eight operands, corresponding to the corresponding elements of the eight columns.

(2) Delete a row: You can also use SNMP to call a set operation to delete a row, which is easier than adding a row. To delete a row, you only need to use the set operation to set any element in the row (SNMP object instance) to "invalid.

However, this operation has an exception: the address translation group SNMP object has a special table (address translation table), which does not define an "invalid" condition for an element. Therefore, in SNMP, the address in the table is set to an empty string, and the empty string is regarded as an illegal element.

When deleting a row, whether or not the element of a row in the table actually disappears is related to the specific implementation of each device (management agent. Therefore, in network management operations, the running management process may obtain "invalid" data from the Management proxy, that is, the deleted content of elements that are no longer in use, therefore, the management process must be able to determine the legitimacy of data through the content of each data field.

The structure of the SNMP Object Tree table is described here.