SNMP Redundancy

Redundancy (in the Plant SCADA context) is a function of the support provided in the SNMP device you are talking to. Some SNMP devices have a fixed IP address of who can talk to them. In this case, only one Plant SCADA I/O server can talk to them and redundancy is impossible.

However, most SNMP devices allow any device to talk to them provided their SNMP community name (like a password) is valid. In this case, Plant SCADA redundancy will work.

For an SNMP device to support trap redundancy (that is, to send traps to multiple places) the device has to support allowing two or more trap IP addresses. Each trap has to be sent to the primary and standby I/O server. If the SNMP device only supports one trap IP address, the standby I/O server cannot receive traps if the primary server is down.