Before you can use the SNMP feature you have to configure the SNMP manager and the SNMP agents (and thereby create a manager DP, and an agent DP that belongs to the manager DP), via the SNMP configuration panels. This chapter describes the SNMP configuration panels for manager and agent configuration. Open the SNMP configuration panel via System Management > Driver > SNMP.
The panel shows the agents for each SNMP manager. Furthermore, you can create new SNMP managers and agents.
Figure: SNMP configuration panel
SNMP ManagerThe agents "SNMPAgent1", and "SNMPAgent2" (see figure above) belong to the manager with the number 1.
A SNMP manager can be chosen from the combo box and the agents belonging to the chosen manager are shown in the table. New managers can be created via the New button. You can create managers with a number from 1 until 255. The manager number 1 exists by default.
The chosen manager can be deleted via Delete button.
Note that when you delete a manager the agents that were configured for this manager, are not deleted! SNMP AgentsThe SNMP agents are queried by the SNMP managers. New SNMP agents can be created via the New button. The new agents are created by using the following panel.
Figure: Create SNMP agent
SNMP Manager: shows the manager for which the agent is created, Agent DP Name: specifies the name for the SNMP agent DP. The entry is read from the config file. You have to set the config entry "agentDPName" or in case of SNMPv3, the entry "v3entityDPName". See Config entries and internal data points. The SNMP Agent ID can be a number between 1 and 255. This means that a manager can query maximum 255 agents. This limit can be modified with the aid of the 'maxAgents' config entry. Name is the name of the agent and is shown in the table on the SNMP agents tab. If you do not specify a name the internal agent data point is shown. IP Address shows the IP address of the agent, e.g. 192.168.1.13, or a computer name, e.g. eiwrk068. If no IP address was set here or it has been deleted (empty string) the agent is disabled and the internal DPE Status.Timeout (see Config entries and internal data points) is set to FALSE independent of the state it was before.
To delete an agent select the agent from the table and right click the table. The manager can be deleted via the context menu.
The configuration panel of the SNMP agent is opened via the context menu (right click on the table) or via double click on an agent in the table.
Figure: SNMP agent configuration
Name: is the name of the agent and is shown in the table on the SNMP agents tab. IP address: The IP address of the agent, e.g. 192.168.1.13, or a computer name, e.g. eiwrk068. If no IP address was set here or it has been deleted (empty string) the agent is disabled and the internal DPE Status.Timeout (see Config entries and internal data points) is set to FALSE independent of the state it was before. The port number: Defines the port number via which the SNMP manager tries to connect to the agent, which is configured here. The default WinCC OA Pmon SNMP agent port is 4700. The port numbers for the SNMP pmon agent and for the live agent can be specified via config entries. The fields read and write community: allow the read and write access to the agent. The read and write community strings are like a password. The community strings are sent with the SNMP request. If the string is correct, the SNMP agent sends an answer (the requested information) to the manager. This entries are only used for the agents to which the WinCC OA system is connecting. The timeout: specifies the time in 1/100s until which the manager has to receive a reply to a SNMP message. The default value is 1 sec. It might ,however, be necessary to increase the timeout in case of longer distances or low networks/agents. Valid values are 1 - 10 sec. Retries: specifies the number of retries that are executed before an error is shown. If a timeout is reached the message is sent newly. You can configure maximal 10 sending retries. (default = 1) SNMP protocol: specifies whether the protocol SNMP v1 or SNMP v2 is used. SNMP live agentsThe live agent provides data point specific data from the DP table of the ETM MIB. The SNMP Pmon agent serves as a proxy for the SNMP live agent. Thus, the data can be provided for external SNMP managers. The Live Agents tab shows the live agents configured for the WinCC OA project.
Further information about the OIDs of the WinCC OA MIB can be found under: MIB - WinCC OA MIB
Figure: SNMP configuration
Click on the push button "New" in the SNMP configuration panel (refer to the figure above) and the following dialog pops up, in which SNMP Live agents can be created.
You can create live agents with the number from 1 to 10. The number can be chosen from the combo box.
The SNMP live
agent configuration panel can be used for configuring the
dp elements that are queried via SNMP (the DPEs are provided by
the SNMP live agent). The SNMP live agent configuration
panel is opened via a double click on the agent in the table or
via the context menu that is opened via right click on the table
(refer to Figure "SNMP configuration" above). Click
on the push button "select data point element"
Technically it would be possible to write (write access) on these DPEs. Since it is not possible to check the user rights, this was, however, omitted.
Figure: SNMP Live agent configuration
The unique number of the live agent (Agent No.) as well as the Name are shown at the top of the panel. The DP Table shows the data points that are queried via SNMP. The data points are chosen via the familiar WinCC OA buttons and are added to the table via the Apply button. The data points contain an index, which is used to communicate with the data points via MIB (e.g. (1.3.6.1.4.1.13828.2.1.20.1.2.idx).The queried data point information is presented on other data points to which a peripheral address was added.
A trap text
can be specified in the lower part of the panel. The trap text is represented on the _LiveAgentNr_SNMPLiveAgent.specificTrap
data point element. The trap is sent to all configured managers
when
The traps are sent via the Pmon agent since the Pmon agent serves as a proxy for the live agent. The default SNMP live agent port is 4701. SNMPv3In order to use SNMPv3 there are some additional optional config entries. Furthermore, the SNMP configuration panel as well as the address config for the SNMP driver were modified. You can now also configure SNMPv3 entities and set the entity type in the address panel. The config entries and the configuration and address panels are described in the following.
Figure: SNMP v3 entities
Limitations: Currently there is no SNMPv3 support in the WinCC OA SNMP Live Agent (WCCOAsnmpa) and in the Pmon.
Figure: create a v3 entity (agent)
If the data point (see figure above) name is changed when creating the agent/entity (default: SNMPAgent or SNMPV3Entity for V3), also the corresponding config file entry (see the SNMP config entries of this document) for the middle part of the data point name (agentDPName or v3entityDPName) has to be set. The middle part of the data point name has to be same for all created data points!
Figure: SNMP v3 entity configuration
An entity is configured in the panel shown above.
Name The name of the entity and is shown in the table on the SNMP agents tab.
IP address The IP address of the entity, e.g. 192.168.1.13, or a computer name, e.g. eiwrk068. If no IP address was set here or it has been deleted (empty string) the entity is disabled and the internal DPE Status.Timeout (see Config entries and internal data points) is set to FALSE independent of the state it was before.
SecurityName The SecurityName describes the user/the program that requires access to the data. The SecurityName has to be unique per SNMP manager.
ContextName The context name on the target computer. The context includes specific MIB objects.
You can specify a context name per entity. If several context areas should be queried on one entity, several data points should be created.
The Management Information Base is the tree which leaves contain the actual data. You can restrict the user access in the SNMP V3 to an area of MIB e.g. everything under the node 1.3.6.2.1.1. Thus, the user can not access anything else.
Port Defines the port number via which the SNMP manager tries to connect to the entity, which is configured here.
Timeout Specifies the time in 1/100s until which the manager has to receive a reply to a SNMP message. The default value is 1 sec. It might, however, be necessary to increase the timeout in case of longer distances or low networks/entities. Valid values are 1 - 10 sec.
Retries Specifies the number of retries that are executed before an error is shown. If a timeout is reached the message is sent newly. You can configure maximal 10 sending retries. (default = 1).
SecurityLevel The security level describes which security measures should be used for the data exchange.
Default value is (1).
AuthProtocol There are two protocols available for the authentication of the SNMP users:
Default value is (1).
An authentication protocol can only be selected, if the setting in the security level is "authNoPriv" or "authPriv".
AuthPasswd The password used for the authentication. This password can only be set, if the setting in the security level is "authNoPriv" or "authPriv".
PrivProtocol The sent data can also be encrypted in order to increase the security. For the encryption a protocol has to be selected.
Default is (1).
An encryption protocol can only be selected, if the setting in the security level is "authPriv".
PrivPasswd The password used for the encryption. This password can only be set, if the setting in the security level is "authPriv".
ContextEngineID The EngineID of the target computer. If this is not specified, it is defined during the query of data. |
V 3.11 SP1
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CAUTION
Note
in the SNMP Live Agent
configuration panel to select a data point element which is available
to the Live_Agent SNMP manager.
is clicked. The config entry
