But sometimes communication was lost temporary
So if available to create another block of mms connect to cn2(172.17.x.x) in the same time in control builder to exchange in parallel with cn1 network To avoid missing communication or it will give conflict in communication
1. Resolve the network issues that are causing you to lose connection. eg is it a hardware failure, network overload, bad cable, incorrect router configurate etc.
2. RNRP is a redundancy handler. It can deal with failed networks lost messages etc. You don't need to program anything in MMS or ComVars for this to work. Make sure RNRP is configured correctly.
Better do as Rob Lyon suggests, let RNRP handle the routing / failover between the primary and secondary networks and concentrate on the reason why traffic is lost. RNRP in modern versions keeps track on lost routing telegrams, use it as an indicator. The RNRP Network Status and Fault Tracer tools can display and reset these counters.
- Examine Control Builder M > Remote System > Controller Analysis > More > Network Information
Overruns, underruns and other Interface counters may reveal an unhealthy controller. Overload and lack of task tuning are common problems. Some CEX-bus units may drain considerable amounts of resources from the CPU, eg fast serial communication with eg Autrosafe/Autronica (fire & gas detection systems) is a known culprit.
- Examine port counters in the switches
Also worth noticing, MMS runs over TCP port 102 and tools like Wireshark can tell you a lot if you capture the traffic. I usually begin with checking what Wireshark's Analysis > Expert Info has to say. Capture of switched traffic can be tricky. I suggest to use Port Mirroring if possible.