Specifications; Snmp Messages - Omron CJ1W-EIP21 Operation Manuals

SNMP Traps
When a failure or some other specific problem occurs, a status report called a trap is sent. This enables
monitoring changes in status even if the SNMP manager does not monitor the EtherNet/IP Unit period-
ically. However, traps use UDP. Therefore, you cannot check to see if the SNMP manager receives traps
from the EtherNet/IP port. Thus, depending on the network status, some traps may not reach the
SNMP manager.
SNMP manager
Trap

11-1-2 Specifications

Item
Protocol
Agent
MIB
Port No.
Timing of SNMP trap opera-
tion
Supported MIB commands

11-1-3 SNMP Messages

The structure of SNMP messages is as follows:
MAC header IP header
Version Community
Item
Version
Community
PDU
CJ-series EtherNet/IP Units Operation Manual for NJ-series CPU Unit (W495)
Controller power supply
turned ON.
MIB
SNMP agent
SNMP
SNMPv1, SNMPv2c
MIB-II
SNMP agent: 161 (UDP)
SNMP trap: 162 (UDP)
These can be changed in the EtherNet/IP Unit Settings from the Sysmac Studio.
Status reports are sent to the SNMP manager at the following times.
• When the Controller is turned ON
• When links are established
• When an SNMP agent fails to be authorized
GetRequest/GetNextRequest
Variable length (1,472 bytes max.)
UDP header SNMP message
PDU
This value gives the SNMP version.
SNMPv1: 0
SNMpv2c: 1
Community name for verification
This depends on the PDU type.
EtherNet/IP Unit
Specification
Set value
11 SNMP Agent
11-3
11