SNMPv1: Simple Network Management Protocol version 1st

SNMPv1 Full name: (SNMPv1: Simple Network Management Protocol V1)

SNMP is a standard protocol used to manage network nodes (servers, workstations, routers, switches, and hubs) in an IP network. It is an application layer protocol. SNMP enables network administrators to manage network performance, discover and solve network problems, and plan network growth. The Network Management System receives random messages (and event reports) through SNMP to learn about network problems.

Currently, SNMP has three versions: SNMPv1, SNMPv2, and SNMPv3. This article describes SNMPv1 information.

SNMPv1 is a simple request/response protocol. When the network management system sends a request, the manager returns a response. This behavior is implemented by using either of the four protocol operations. These four operations are get, getnext, set, and trap. NMS obtains one or more object (Instance) values from the SNMP agent through the get operation. If the agent cannot provide all the object (Instance) values in the request list, it does not provide any values. NMS uses the getnext operation to request the proxy to retrieve the next object instance value from the request list or object list. NMS sends commands to the SNMP agent through the set operation and requires reconfiguration of object values. The SNMP Agent notifies NMS of a specific event from time to time through the trap operation.

For more information about SNMP, SNMPv2, and SNMPv3, see the relevant section.

 

Protocol Structure

 

SNMP is an application.ProgramProtocol, encapsulated in UDP. Common SNMP information formats of different versions are as follows:

 

Version

Community

PDU

 

Version: SNMP version number. The manager and agent must use the same version of SNMP. You need to delete information with different version numbers without further processing them. Community: group name, used to authenticate the manager before accessing the proxy. PDU (SNMPv1): There are five different types of PDU: getrequest, getnextrequest, getresponse, setrequest, and trap. For details about each part, see the following:

 

The getrequest, getnext request, getresponse, and setrequest PDUS formats are as follows:

 

PDU type

Request ID

Error status

Error Index

Object 1, value 1

Object 2, value 2

...

 

PDU type: indicates the PDU type to be transmitted: 0 getrequest; 1 getnextrequest; 2 getresponse; 3 setrequest. Request ID: Connection SNMP request and response. Error status: indicates an error and error type. This field can be set only for the response operation. For other operations, this field is set to 0. Error index: connects an error and a special object instance. This field can be set only for the response operation. For other operations, this field is set to 0. Variable bindings: Used as the data field of the SNMPv1 PDU. Each variable is bound to a special object instance under the current value (except for the get and getnext requests, the values are ignored ).

 

The format of the trap PDU is as follows:

 

PDU type

Enterp

Agent ADDR

Gen trap

Spec trap

Time stamp

OBJ 1, Val 1

OBJ 1, Val 1

...

 

PDU type: Specify the PDU type for transmission (trap = 4 ). Enterprise: identifies and manages an enterprise and defines trap under its registration right. Agent Address: the IP address of the agent for further identification. Generic Trap type: Describes the event report fields. The following seven values are defined. Specific trap type: This type is used to identify non-generic traps when generic traps become a type specified by the enterprise. Timestamp: the value of the sysuptime object, indicating the time between the initial value setting and the occurrence of the corresponding trap.