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Reserve Your Seat TodayGET requests at regular intervals are used in the same manner as an ICMP ping to automatically detect if an SNMP device is online.
An "SNMP ping" is a method of achieving "heartbeat" or "keep-alive" functionality with SNMP communications.
Let's start with a quick review of a typical ICMP ping. That's an IP-based signal sent from one device to another. If the target device receives the "ping" from the source device, it will (if configured to do so) respond to confirm that it is active and connected to the network. It's a nice, simple way of confirming that a device is online.
The problem with ICMP pings is that they operate on a fairly superficial layer. If you've worked with IP networks for a while, you've surely run across a situation where a device is "frozen" but can still respond to pings. In cases like this, a simple ping just isn't complex enough to be a good test of actual device status.
SNMP devices in your network support a more reliable ping method based on GET requests. As you'll recall, an SNMP GET message is sent by the manager to a device to request a specific value. If you want to know the temperature reading at a remote site right now, your manager will send a GET request to the local SNMP RTU to demand the sensor value.
A smart SNMP manager can take advantage of the call-and-response GET mechanic to send a kind of "SNMP ping". On an automated schedule (one every 3 minutes, for example), your manager will send an SNMP GET to the device. If the device responds, all is well. If no response is received after a few successive requests, your manager can conclude that the device is offline and an alarm must be reported.
If you had only been using common ICMP pinging, your device might have continued to respond despite being in a failed state. Your monitoring system would have been vulnerable and you wouldn't have known it. SNMP-based pings, in this case, were a much better option to ensure your SNMP-based equipment was still online.
ICMP is primarily a diagnostic tool used for error reporting and network troubleshooting. It operates at the network layer and is commonly associated with tools like ping. ICMP messages report issues such as unreachable hosts or excessive delays, making it useful for quick, low-level communication about network problems. However, ICMP has limited security, which is why it's often restricted in networks to avoid exploitation in attacks. It doesn't provide extensive details or control over devices; instead, it focuses on error reporting and diagnostic functions.
On the other hand, SNMP is designed for in-depth monitoring and management of network devices like routers, switches, and servers. SNMP operates at the application layer, gathering performance metrics, uptime statistics, and configuration data remotely. Unlike ICMP, SNMP offers more control, allowing administrators to configure devices and receive real-time alerts through SNMP traps. The latest version, SNMPv3, also includes strong security features such as encryption and authentication, unlike older ICMP. When considering ICMP vs SNMP, ICMP is better for quick diagnostics, while SNMP is the go-to protocol for detailed network management and control.
Reach out to us at 1-800-693-0351 to discuss equipment that includes the SNMP ping function.
