SNMP I/O Configuration Manual
Introduction
This document describes how the SNMPManagerIO component works, how to set it up and use it within a CDP system. It also describes basics about the SNMP protocol.
The SNMPManagerIO is able to send SNMP Set and Get requests to several SNMP agents. Get requests can be sent regularly, specified by two different intervals. Get request Responses from agents can be used to update CDP Signals. The SNMPManagerIO is able to receive and decode SNMP Trap messages sent from several sources. The different Traps can either be configured to Set/Clear CDPAlarm, or to generate property change Event. If communication with SNMP Agents on different ethernet-interfaces is needed, several SNMPManagerIO components can be created, each working on a separate ethernet-interface. The SNMPManagerIO supports SNMP v.1 and 2. When configuring Requests and Traps, the OIDs of the variables must be known. Vendor of the device (SNMP Agent) should have this information (MIB). Another possibility is to use a MIB Browser to retrieve this information.
Terms and Definitions
| SNMP | Simple Network Management Protocol. A protocol using UDP that enables a management station to configure, monitor, and receive trap messages from network devices. |
| SNMP Agent | Software that enables a device to respond to manager requests to view or update MIB data, and send traps reporting problems or significant events. |
| MIB | Management Information Base. A logical database made up of the configuration, status and statistical information stored at a device. MIB-files are readable text-files. |
| OID | Objec Identifier, a string of numbers derived from a global naming tree, used to identify an object. E.g.: '1.3.6.1.4.1.16177.1.1.9.1' |
| Get Request | A manager-to-agent request to retrieve the value of a variable. A Response with current values is returned. |
| Set Request | A manager-to-agent request to change the value of a variable. A Response with (current) new value for the variable may be returned. |
| Trap | Asynchronous notification from agent to manager. SNMP traps enable an agent to notify the management station of significant events by way of an unsolicited SNMP message. |
| BER | Basic Encoding Rules - A set of rules for translating ASN.1 values into a stream of octets to be transmitted across a network. |
Configuration of SNMP I/O Server
The SNMPManagerIO can be added to the selected application from the Resource tree under SNMPIO.
SNMPManagerIO Transport
The SNMPManagerIO Transport table makes it possible to configure how to send and receive SNMP messages.
| Name | Value | Description |
|---|---|---|
| Name | NetworkTransport | The name of the transport |
| Protocol | SNMP | The Ethernet protocol used. |
| LocalName | ETH0 | The name, as specified in the Application NetworkInterface, of the local ethernet interface to use. |
| SetGetPort | 161 | The port to send to, used for Set- and Get-Requests. 161 is reserved as destination port for SNMP Set- and Get-Requests, but may be configured to another value if the SNMP agent(s) needs that. |
| TrapPort | 162 | The port to listen for incoming Traps. 162 is reserved as destination port for Traps sent from SNMP agents, but may be configured to another value if the SNMP agent(s) needs that. |
| OwnSrcPortPort | 30543 | The port used as Src-port when sending Set- and Get-Requests. SNMPManagerIO will listen on this port for incoming Responses. Can be any available port number (1-65535), but numbers <1024 are typically reserved by the Operating System and require Administrator permissions to access. |
| Model | SNMPIO.NetworkInterface |
SNMPManagerIO Properties
There are 3 extra properties for the SNMPManagerIO: PollInterval1, PollInterval2 and TimeoutLostContact. PollInterval1 and PollInterval2 specifies in seconds two different intervals for how often to send a GetRequest. TimeoutLostContact specifies number of seconds without getting any reply of GetRequests, before setting LostContact alarm for an agent. Value should be at least twice as large as the smallest PollInterval to avoid setting alarm unnecessarily.
Configuration of SNMP Agent
To be able to send and receive SNMP messages, you must first add one or more SNMPAgent resources to the SNMPManagerIO. Give the SNMP Agent a Name, specify the agent's IP address in RemoteIP and choose SNMP version 1 or 2.
| Name | Value | Description |
|---|---|---|
| Name | SNMPAgent | The name of the SNMP Agent |
| RemoteIP | 127.0.0.1 | The IP address of the remoteSNMP Agent to communicate with. Must be on the same subnet as LocalName configured in Transport. |
| SNMPversion | 2 | The SNMP version the agent is using. SNMPManagerIO supports 1 and 2. |
| Model | SNMPIO.SNMPAgent |
Configuring what to send and receive
Inside the SNMP agent, you may choose between SetRequest, GetRequest, ReceiveAlarmTrap and ReceiveEventTrap from the Resource tree.
SetRequest
To be able to change/set a value inside the SNMP Agent, add a SetRequest from the Resource tree.
| Name | Value | Description |
|---|---|---|
| Name | SetRequest | The name of the SetRequest |
| OID | 1.3.6.1.4.1 | The Object Identifier for this SetRequest. |
| DataType | INTEGER | What datatype to use/how to encode the SetValue. |
| Community | private | What community to use, usually private or public. |
| SetValue | The value to send to the SNMP agent. | |
| Model | SNMPIO.SetRequest |
GetRequest
To be able to retrieve a value from the SNMP Agent, add a GetRequest from the Resource tree.
| Name | Value | Description |
|---|---|---|
| Name | GetRequest | The name of the GetRequest |
| OID | 1.3.6.1.4.1 | The Object Identifier for this GetRequest. |
| DataType | INTEGER | What datatype to use for the GetValue. |
| Community | private | What community to use, usually private or public. |
| PollInterval | 2 | How often to send the GetRequest. Value 1 and 2 corresponds to PollInterval1 and PollInterval2 in the Properties for SNMPManagerIO. Value 0 means sending once (or until receiving Response). |
| GetValue | The value retrieved from the SNMP agent. | |
| Model | SNMPIO.GetRequest |
If you want a CDPSignal to be updated with the value retrieved from the GetRequest, click at the GetRequest and add a CDPSignal of correct type under CDPCore from the Resource tree. Only the following types can be converted to a CDPSignal: BOOLEAN, INTEGER, COUNTER32, GAUGE32, UINTEGER32 or COUNTER64.
ReceiveAlarmTrap
The SNMP Agent must be set up to send traps to the SNMPManagerIO. This is done by configuring the SNMP Agent to send traps to the same IP Address that the SNMPManagerIO application runs on. If a received trap shall Set/Clear a CDPAlarm, where one OID shall Set a CDPAlarm, and one OID shall Clear the same CDPAlarm, add a ReceiveAlarmTrap from the Resource tree.
| Name | Value | Description |
|---|---|---|
| Name | ReceiveAlarmTrap | The name of the ReceiveAlarmTrap |
| OID_Set | 1.3.6.1.4.1 | The Object Identifier causing the CDPAlarm to be Set. |
| OID_Clear | 1.3.6.1.4.1 | The Object Identifier causing the CDPAlarm to be Cleared (different than OID_Set). |
| ValueToSetClearAlarm | Optional. If you specifiy a value here, the CDPAlarm will only be Set/Cleared if the value received together with the OID_Set/OID_Clear match this value. | |
| Model | SNMPIO.ReceiveAlarmTrap |
ReceiveEventTrap
The SNMP Agent must be set up to send traps to the SNMPManagerIO. This is done by configuring the SNMP Agent to send traps to the same IP Address that the SNMPManagerIO application runs on. If a received trap shall trig a CDP Event, add a ReceiveEventTrap from the Resource tree.
| Name | Value | Description |
|---|---|---|
| Name | ReceiveEventTrap | The name of the ReceiveEventTrap |
| OID | 1.3.6.1.4.1 | The Object Identifier causing the Event to be trigged. |
| TrapValue | If this Trap/OID is received, TrapValue will contain the received value in the trap. | |
| Model | SNMPIO.ReceiveEventTrap |
If this trap contains several OIDs (and correspondign value), which you want to trig Events for, click at ReceiveEventTrap and add SubOIDEvent from the Resource tree.
| Name | Value | Description |
|---|---|---|
| Name | SubOIDEvent | The name of the SubOIDEvent |
| SubOID | 1.3.6.1.4.1 | Another Object Identifier causing an Event to be trigged. |
| TrapValue | If this Trap/OID is received, TrapValue will contain the received value in the trap. | |
| Model | SNMPIO.SubOIDEvent |
Get started with CDP Studio today
Let us help you take your great ideas and turn them into the products your customer will love.