Jochen Schulz

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Which switches support PRTG / SNMP?

Jochen Schulz

If looking at the PRTG examples in the last blog article gave you an appetite for solid network monitoring, very good! Then the question will probably go through your head: are my switches even supported by PRTG? Or which switches would be considered for future purchases?

First of all, clarification: most current managed switches are well suited for small to medium-sized networks, including Dante or other audio applications. In this blog article I have listed the most important features and compared common switches.

Today the only question is whether or to what extent a switch can be queried by a network monitor via SNMP. Regularly checking all parameters of a switch is very time-consuming and quite annoying. Software like PRTG, for example, does this once a minute and immediately informs you if parameters are not set as they were originally intended.

I've come across some switches a lot in recent years in audio or theater installations. I now have most of them in my small laboratory so that I can test certain scenarios at my leisure.

To summarize my findings I created the following table, which hopefully shows at a glance which parameters can be monitored via SNMP on the various switches.

I tried to select the most important parameters that could be relevant for Dante audio and control networks. If you are missing a parameter from the list, feel free to send me a short message and I will try to add it!

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Not all switches can be read equally well and like an open book. The question about PRTG or SNMP support is therefore entirely appropriate.

A short classification:

Cisco SG350 / CBS350

All of the parameters that I have touched on Dante networks so far can be monitored via SNMP. Cisco provides extensive MIB files on its homepage, so that nothing is left to be desired. The sheer flood of parameters and thus MIB files and OIDs can be overwhelming and requires a lot of patience until you find the respective parameter.

HP Aruba 2530

HP also offers extensive MIB files. All relevant parameters can be queried.

By the way, the ○ symbols in the table don't mean anything bad. For example, there is no global parameter that can be used to completely turn IGMP snooping on or off. You could also say that IGMP snooping is always switched on globally and can be activated directly per VLAN if necessary.

The Aruba does not offer to switch between access and trunk mode per port. Instead, all VLANs must be added as tagged for the respective port. Technically it comes out the same - if you haven't forgotten a VLAN. However, this makes configuration and monitoring somewhat more complicated and error-prone.

Netgear M4250

The Netgear site offers an exemplary number of MIB files for download. Accordingly, all desired parameters can be easily found with a little patience.

Even though I have an M4250 in my rack myself, there are still a few question marks on my list. Unfortunately, my model does not offer PoE. Accordingly, I cannot verify whether the parameters can be queried via SNMP.

For the Energy (EEE) and AutoTrunk functions, I am inclined to give it a “not possible”. Despite an intensive search in all MIB files, no OID could be found. But I haven't completely given up yet. If you have already found the parameter and are using it in your monitoring: I would be very happy to hear from you!

Only the DHCP server function is a bit unfortunate. Instead of specifying an exact area per pool like Cisco and thus knowing exactly how many addresses are still free, Netgear only lets you specify the address ranges that should NOT be allocated. Unfortunately, it is not possible to query the number of addresses that are still available. You will therefore not be able to set an alarm once that number reaches zero.

Luminex Gigacore

To this day, the Luminex switches still give me very mixed feelings. On the one hand, it is absolutely commendable that a hardware manufacturer is taking on the matter and developing tailor-made switches for our rather small audio sector. And many of the functions and the GUI are actually tailored to a sound engineer and not an IT specialist compared to Cisco or HP, so that there are definitely (sound) colleagues who prefer to take a Luminex with them on tour instead of a Cisco.

It's understandable that Luminex doesn't have the development budget that Cisco does. Accordingly, the focus is on the actual function as a switch. SNMP monitoring is probably rarely used and is therefore not (yet) at the level of other manufacturers.

The good news: Luminex generally supports SNMP. In particular, querying traffic per port is possible. Uplinks and connected devices can at least be monitored.

Otherwise, the Luminex unfortunately doesn't spit out much via SNMP. Not a single MIB file is available for download on the Luminex site. For a fixed installation that is supposed to run solidly for a few years, this makes support and any troubleshooting a little more difficult. If you want to check whether, for example, IGMP snooping is set in all Dante VLANs, you have to manually log into each individual switch and dig through the menus. PRTG would report this immediately if the sensors were set up accordingly and would also show exactly which switch has changed and even since when.

For temperature monitoring, you can be happy if a Cisco is installed in the same room and you can therefore notice failures in the air conditioning system via other means.

SNMP or network monitoring is probably not the main argument for choosing your switches. But if you are about to purchase several switches for a permanent installation and are torn between two manufacturers, it might not be a bad idea to think about network monitoring at a later date!

In addition to switches, there are many other devices that actually have nothing to do with networking, but still understand SNMP and can be monitored. Listing them all with their respective SNMP functionality would go beyond the scope. And whether it makes sense to monitor every refrigerator and every coffee machine is of course also questionable. But keeping an eye on redundant power supplies on audio matrixes or mixing consoles, or the storage space on a NAS, makes the daily routine check before the performance much easier.

And if you monitor something in your venue already that I haven’t mentioned here, let me know! Always fun to get some feedback and learn something new!

Further articles about IT networks / Dante: