Interestingly, my snmpwalk only returns 93 lines, but there are certainly more (I think), but why aren't they showing during an snmpwalk query? Is there another Linux way to query more lines? I want to graph RSSI over time per sub. Is there another reference for SM's running 3.4 somewhere?
As far as your snmpwalk, you are seeing all the generic OIDs (SNMPV2 and IF-MIB) but nothing from the Cambium-specific OIDs. If you want to walk all the Cambium-specific fields, try "snmpwalk -v2c -ccommunity 1.2.3.4 .1.3.6.1.4.1.17713 | less" or something similar (or substitute 'cambium' for '.1.3.6.1.4.1.17713' if you have the MIB file properly installed in the path used by snmpwalk and snmpget, like in /var/share/snmp/mibs). (piped through 'less' because there's hundreds of lines of reply coming)
On your specific RSSI question: The field you're checking is probably not the one you really want. (It exists only after eDetect has been performed to look for interfering signals)
Try .1.3.6.1.4.1.17713.21.1.2.3.0 (cambiumSTADLRSSI.0) for the Downlink RSSI. You can also hit .1.3.6.1.4.1.17713.21.1.2.18.0 (cambiumSTADLSNR.0) for Downlink Signal to Noise. You might be interested in .1.3.6.1.4.1.17713.21.1.2.6 (cambiumSTAUplinkMCSMode.0) and .1.3.6.1.4.1.17713.21.1.2.7 (cambiumSTADownlinkMCSMode.0) as well.
which I could guess relates to something in the downloaded list like:
cambiumEffectiveSSID OBJECT-TYPE
SYNTAX DisplayString (SIZE(0..128))
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"Effective SSID
Device Allocation: AP"
::= { cambiumGeneralStatus 11 }
Should I use something like snmptranslate? I put the downloaded CAMBIUM-ePMP-3.4-MIB.txt in /usr/share/snmp/mibs (Debian 8.11).
I eventually want to use rrd/mrtg (or some combination) to roll my own graphs, and want to understand how to grep the counters. I guess I could just map RSSI over time, that would be useful, but I also want to understand how rrd/mrtg views an entry like:
If your MIB.txt is in the current directory (if not, change it to where it is, I couldn't get snmp to recognize it was in /usr/share/snmp/mibs/ for some reason). It should map the outputs to actual device values and give you a text file you can study containing something like:
As you can see, there's some useful information in there that you could graph if you're building your own code with this.
The reason I originally didn't get what I wanted with snmpwalk was because I didn't understand the snmp structure. The first numbers are just generic to everything that uses snmp, you have to look at the data past the unique identifier of Cambium, which is 17713, so that's why you do:
I usually run Ubuntu on our servers, so very similar to Debian in most ways. You need to figure out how to get your snmpwalk, snmpget, etc to correctly recognize and parse all the MIB files - you should be able to get this type of output:
If snmpwalk and snmpget can't handle the translation for you, very likely snmptranslate won't either. They all normally read the same set of MIB files. Normally, you need to explicity pass "-On" to force numeric output when that's what you need, otherwise it defaults to the textual labels defined in the MIB files.
You should check the documentation under "man snmpcmd" - that's options common to most/all of the net-snmp tools. Depending on how you're actually polling the data, if you're using "snmpget" you can use "-OvU" for example to get ONLY actual field data, not the field name or units or anything extra. So for example in a bash script you can do things like:
I'm building the rrd right now, trying to figure out how to get it to scale to negative numbers and wondering if I need log scale to show signal strength and noise floor in easier to understand values? I'll probably just make it linear so our techs can understand if they're going up or down. I'm polling every 10 minutes. Later, once I get it working right, I'll poll to mysql db and use rrdtools to update and build graphs.
Later, I'll superimpose all the various MCS packet counts on a separate graph so we'll know what's going on with a sub. Will post back here if anyone else finds it useful?