Out of Band Access is one of 8 Reasons to Choose RTU vs Embedded Monitoring.
An out of band network is an important tool that allows you to see your equipment without primary network connection. It essentially provides you with a backup path in case of network communication failure.
Your individual devices can have out of band access if they're really critical, but it's an especially important feature for remote management. Many problems with your primary transport can be fixed with simple commands. It might be as simple as a reboot. The only requirement is that you have some other way to send the command while your transport is offline. Out of band access provides this other way to receive data and send commands.
An example of out of band access is a serial port connected to an out of band modem that provides dial-up access to the router. It might be an overhead channel on a microwave system. Your normal payloads are carried in the main channel, but you get an overhead channel that is outside of the normal band (out of band). Other examples include T1 when you use LAN as your primary method. It's also becoming more common to use cellular connections as a backup for LAN.
You've decided it's time to buy an RTU to monitor your remote sites, but how do you decide which model is the best fit? Today, we're going to look at the top 3 things you need to think about when you're choosing an RTU...
by Andrew Erickson on February 11, 2019
If you rely on any one data path to connect to your remote sites, you're at risk for losing communications. You'll have to send a tech to the site. This is why it is critical for your remote monitoring equipment to support out-of-band access. Two possible choices are LAN with dial-up backup or LAN with serial backup.
Having a backup communications path is especially important in a remote monitoring and control context. If your primary communications go down, you have a problem. With a backup channel available, you can access your alarm remote at the site and execute a fix remotely. For more serious trouble (equipment failure, overheating), at least you can send your tech out to the site with a good idea of what's happening. Knowing what replacement parts to bring is key.
Even if you're using a serial connection or LAN as your main alarm-reporting channel, a dial-up modem can still be a useful backup data path. If anything goes wrong with the serial connection, you can still receive alarms via dial-up reporting.
SNMP management information travels the same network path as your data. It uses the same WAN and LAN routers, hubs, and communications links. And that is the problem. While the network is operating normally, SNMP packets flow between the managed devices and the management workstation with no problem. Its TRAPs, SETs, and GETs all flow with the same priority as regular traffic on the LAN/WAN and provide management information to the workstation or commands to the controlled devices. However, when the network goes down or is severely disrupted, SNMP traffic has no way to get between the managed device and the management workstation. Telnet is usually used along with an SNMP workstation. Telnet packets are also unable to move between the management workstation and managed devices during those network issues.
NetGuardian 832A's dial-up connection can be used as a main or backup path for reporting SNMP traps
Are you in the process of evaluating SNMP manager vendors? Remember, that not all masters are created equal, and not all of them are going to fit perfectly into your network requirements. To build an effective remote alarm management system, it's important that you find the best solution for you.
by Andrew Erickson on April 15, 2019
With out-of-band access, a second path is open to the managed devices that do not depend on the LAN/WAN. It is usually an RS-232 access switch connected to the management port of each device. Every network device that supports SNMP also contains a RS-232 management port. Although it doesn't provide the fancy GUI interface of most SNMP workstations, this method provides the native interface for each device being controlled.
You've decided that it's time for better remote monitoring visibility of your sites. You're doing research about the best SNMP managers, the capacity requirements of the site you're monitoring, comparing free vs. paid, and trying to get an understanding of that perfect-fit setup for your sites. However, the question that's always in the back of your mind - and in the mind of your boss - is how much will an SNMP manager cost?
by Andrew Erickson on December 3, 2019
No, they work with each other. System cost increases only slightly when adding out of band access management, while functionality goes up quite a lot. The SNMP GUI can be used for normal network monitoring and metrics, alarm reports, and data reduction. Then, when problems surface, you can connect to the remote access switch for direct control of your remote equipment. Since there is direct access to the management port, troubleshooting doesn't have the added complexity of a network coming between the device and the technician. And when the network is down, the same connectivity is still there. This provides a direct link between the technician and the device causing the problems.
Being able to access your remote monitoring system is an absolute requirement at all times. It's the lifeline of all of your revenue-generating equipment. That's why your monitoring gear must always be the last thing to fail. To this end, good alarm remotes and masters are designed with redundant power supplies, redundant fuses, and redundant storage devices. Similarly, they should have more than one reporting channels to enable instant failover if one channel goes down.
An important aspect of using RTUs (remote telemetry units) for monitoring is the collecting and reporting of data from your remote sites. Your monitoring system needs a way to collect this data and report it to you via...
by Andrew Erickson on May 3, 2019
Buying a remote monitoring device (an RTU or master station) is an expensive investment. Not only does it have an out-of-pocket cost, but this device is also something you'll depend on. If you don't have visibility of...
by Andrew Erickson on February 22, 2019
If you want to start the process of implementing a remote monitoring or SCADA system in your network, then you're probably wondering if you should use an RTU or a PLC. You might be more inclined to choose an RTU if you...
by Andrew Erickson on April 26, 2019
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