air-ap1572EAC snmp OID to get RSSI and Signal strength

[yleduc]

Hello all,

I am trying to obtain signal quality and strength using snmp. I see that the OID are 1.3.6.1.4.1.9.9.273.1.3.1.1.3 and .4

When I try to retrieve those values using snmpget, I get that these values don't exists. There has to be something else needed to identify the actual association to be probed.

if someone could provide an example on how to call those entries, it would be great !!

Thanks for your time.

[balaji.bandi]

is this managed by WLC or Autonomous AP ?

in general are you able to any results when you do snmpwalk against AP ?

check some reference OID :

https://support.solarwinds.com/SuccessCenter/s/article/Wireless-OIDs-polled-in-NPM?language=en_US

what NMS or snmp tool you using ?

[yleduc]

these are autonomous. air-ap1572-eac. running 15.3.3 jc. I am just using snmpget.

[balaji.bandi]

Can you post AP configuration?

[yleduc]

I don't see how providing the config would actually help in retrieving those values.

[Rich R · Accepted solution]

You do understand how SNMP works right?
Those are rows in the cDot11ClientStatisticEntry table
https://snmp.cloudapps.cisco.com/Support/SNMP/do/BrowseOID.do?local=en&translate=Translate&objectInput=1.3.6.1.4.1.9.9.273.1.3.1.1#oidContent
Which is closely related to the  cDot11ClientConfigInfoEntry table:
https://snmp.cloudapps.cisco.com/Support/SNMP/do/BrowseOID.do?local=en&translate=Translate&objectInput=1.3.6.1.4.1.9.9.273.1.2.1.1#oidContent

You can't GET a row of a table - you can only get an individual instance/value in that table and you need to know how to instantiate the entry you're looking for.  In this case the entries are encoded from the BSSID MAC and the client MAC and a few other parameters.  If you want to see what the table looks like then do an SNMPWALK on the table: 1.3.6.1.4.1.9.9.273.1.3.1.1
There you'll see that for each variable in the table you have a value for each client.  If you want to use snmpget you'd need to get the full instantiated OID for the client you want to get - and that will change depending on which SSID or radio the client is connected to.

[yleduc · Accepted solution]

Hello rrudling.

You do understand how SNMP works right? I am no expert but know enough to get by most of the time. Somehow in this case, when doing the snmpwalk on the device, I could not see anything related to that table. I did not know about doing the snmpwalk on the table OID  (1.3.6.1.4.1.9.9.273.1.3.1.1) as you mentioned. Doing so, gave me the needed information to retrieve the necessary values.

I am looking at the actual OID, the only thing that I don't understand is the last 7 in the OID prefix (1.3.6.1.4.1.9.9.273.1.3.1.1.3.7). Any idea what it represent? This is basically what I was missing for my request.

Thanks again for your help.

[Rich R]

It's not part of the prefix - it's part of the instance or index number of the entry.

I could see see that it was using (amongst other things) radio, BSSID and client MAC but you'd have to work out what all the components are.  Looking through the related config table MIB definition might have more info.  Things like interface index are commonly used in indexing too.

[yleduc]

Hello rrudling.

going back to the snmpwalk result starting from the top (no oid provided), it shows me the ifindex of 7 for the radio interface where the communication takes place.

for other people trying to obtain those oid values, as rrudling mentioned the snmpwalk on oid  1.3.6.1.4.1.9.9.273.1.3.1.1 gave me the info I needed. If you want your result to only show the oid and result, you can use the -O n option.

the actual breakdown is the following:

.1.3.6.1.4.1.9.9.273.1.3.1.1 to access the table

field to access, ifindex of the interface, number of characters in the ssid, ascii value for each char of the ssid, dec value of the 6 bytes of the client mac address.

in order to retrieve the RSSI value for device with mac address of 0011.2233.4455 connected to radio1 (ifindex of 7) with ssid of "ssid", you can use the following oid

.1.3.6.1.4.1.9.9.273.1.3.1.1.3.7.4.115.115.105.100.0.17.34.51.68.85

Thanks again rrudling for your help