If you are responsible for a remote monitoring system with asynchronous transmission, then you are probably faced with moments when you don't know if device silence means "no problems" or "I am offline".
It's not practical to simply wait for asynchronous alarm messages from your RTUs. After all, you might wait forever as your network falls apart. When a device has been silent for a long time, it's critical to act quickly and test if this network element is reachable to check on its status.
That's where pinging network elements come into play.
In this article, we'll walk through what a ping is, its benefits, and real-world scenarios.
The ping command is a basic yet essential capability in network management. It allows you to monitor device availability, network latency, and packet loss. In other words, a ping helps you make sure all devices with an IP address on your network are online. Pinging ensures that all of your devices are alive, available, and working as expected.
A ping alarm is a notification automatically sent to you and your team when one of your LAN connected devices fails to respond to a series of successive pings. Advanced RTUs allows you to configure scheduled pings to a large number of devices every couple of minutes. Some RTUs can support ping alarming to as many as 32 different IP addresses at the same time.
Ping alarms make sure that your network equipment is working properly and as expected. If no response is received from a particular piece of gear, it is assumed that that device is down and needs to be addressed. Addressing it could mean power cycling it, installing new cables, or maybe replacing the unit altogether.
A typical ICMP ping is an IP-based signal sent from one equipment to another. If the target device receives the ping from the source device, it will (as long as it is configured to do so) respond to confirm that it is active and connected to the network. This is a simple, easy way to confirm that your device is online.
The main issue with ICMP pings is that they operate on a superficial layer. This means that they can "freeze" but still respond to your pings. In cases like these, a simple ping simply isn't complex enough to be a reliable test of actual device status.
A SNMP Get message is sent by the manager to a device to request a specific value. So, if you want to know the real-time temperature reading at a remote facility, your SNMP manager will send a Get request to the local RTU to ask for the sensor value.
A smart manager allows you to take advantage of the call-and-response Get structure to send an SNMP ping. On an automated schedule that you previously set, your manager will send an SNMP Get to a device. If it responds, then there are no problems in your network. But, if no response is ever received after successive requests, then your manager can reach the conclusion that the device is offline and will send you an alarm to report that.
If you are using ICMP pinging, chances are your device might continue to respond despite being in a failed state. You lost your visibility over your network and you don't even know it. SNMP-based pings, in this case, are a much better option to make sure you know when your network equipment is still online.
Pinging your remote devices is not useful only when they have been silent for long periods of time. There are other circumstances where pinging can help you troubleshoot other situations in your network.
For example, your IP RTUs can't connect to LAN. Here's a simple step-by-step on what you can do:
Not a long time ago, we had a telecommunications company reach out to us because they wanted to be able to ping IP elements and receive SNMP traps if a device fails or goes offline. After talking to them during our network consultation meeting, we established that they needed to monitor the online status of IP elements from their SNMP manager.
For that, we gave them two options to choose from:
Both the T/Mon and the NetGuardian 832A have ping alarm functionality. So, either unit is able to ping IP elements and send an SNMP trap to this company's SNMP manager if their network element does not respond to the ping.
In this case, the company choose to invest in the T/Mon master station. But, if you have a similar scenario, keep in mind that the device you should choose will depend on the scale of your needs. The NetGuardian can ping up to 32 IP addresses while the T/Mon LNX can ping up to thousands of IP addresses - dozen of which are simultaneous.
Since you're doing your research about ping and ping alarms, you probably already found different sites offering free ping alarm software that you can simply install on your PC. This software certainly has its intended target audience, which should never be industrial networks. Since freeware are usually untested and unreliable, not only your network visibility will be compromised but you risk the safety of your data as well.
The only tool you should trust to take care of your mission-critical network is a software with its own dedicated hardware.
The NetGuardian family of RTUs is designed and manufactured to support a broad number of ping alarms. In fact, most devices support ping-based monitoring of 32 different IP addresses. And, I've said previously, depending on your capacity needs, you might want to choose the T/Mon LNX master station - which supports more ping alarms than you'll ever be able to use.
These units can alert you via email, text message, and even phone calls that a number of consecutive pings to a device failed. Aside from ping functionality, you can also monitor any other aspect of your network as well, such as sensors, propane tanks, doors and etc., for a complete monitoring system.
For more information about our devices, and to know what's best for your unique scenario, give us a call.
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