We are noticing a trend recently where 450 3G SMs that have been deregistered and deleted from our CBRS instance are still registering in the AP and checking into Maestro. Looking at a radio this morning that we deregistered back in May of this year that is online and accessible, but not listed in our CBRS tool. If a customer closes their account or fails to pay, we have been deregistering and deleting the 3G SM from Maestro to kick the radio offline until we can recover the equipment or until the customer restores service. This is no longer working to keep the radio offline.
Looking at the CBRS log in the AP for this particular radio, it looks like there was an INVALID_DEVICE message, but then the SAS reported the SM was already registered so allowed it to pull grant:
08/30/2024 : 09:47:03 CST : Received code: [INVALID_DEVICE] error message: [Device not found or invalid device] from cnMaestro for SM Config Pull Request
08/30/2024 : 09:47:03 CST : CBSD is already registered with SAS
08/30/2024 : 09:47:03 CST : Reusing existing grant with SAS - Frequency = OURFREQUENCY kHz
08/30/2024 : 09:47:03 CST : Enabling session for SM
08/30/2024 : 09:47:03 CST : Grant pull Acknowledgement received from SM
Verified in our Maestro instance that the radio is not listed in the CBRS tool at all.
Is this expected? We are working on upgrading our Maestro on-prem from v3 to the current version, currently on 4.1.0-r3
I don’t have an answer to your question, but often observe cnMaestro being very out of sync with reality when it comes to CBRS grants. For example, sometimes we will see large numbers of SMs in the CBRS tool showing either as registered or unregistered even though they received a grant weeks ago and continue to work and renew grants.
If you have direct access to your SAS provider’s data, look there to see if any of the removed SMs are actually still registered there. I suspect you will find that they still may be registered even though they have been removed from cnMaestro.
I’m going to guess this is the issue. Which makes me wonder what changed because I had been manually auditing Federated to make sure the devices we deregistered in Maestro were coming out of that system, and they were matching regularly so I stopped auditing and assumed it was working as expected. I’ll double check that system to make sure; however, I would expect that if we can register the device to the SAS through Maestro, then DE-registering the device through Maestro should interact with the SAS to remove the registration.
I audited our Granted and Registered list in the SAS and found 6 devices that had been previously Deregistered and Deleted from Maestro over the past year that were still listed as Registered in DPV; I have manually deregistered those devices from DPV. I had one device that needed to be removed from our Maestro network so Deregistered the device, then Deleted it; checked DPV and it was properly deregistered. Doesn’t happen all the time but is happening. I will be manually auditing the SAS list again because of this issue. Hopefully its just a version mismatch issue that will stop once we finish upgrading our on-prem…
Deregistering CBRS devices from CnMaestro is fully supported and in general works. It looks like something might have failed in some of your deregistration cases. But I’m wondering if, in your case, the deregistration succeeded, but then the radio re-registered again later. A deregistration operation, independent of where it was initiated from, will not remove the CBRS CPI parameters from the SM itself. Was the SM immediately powered down after the deregistration and delete cnMaestro operation? One possibility is, if the radio remained mounted and powered up for, say, a few days after the deregistration and delete operation, if in the meantime the parent AP was rebooted, it’s possible the SM simply reregistered. Then a day or 2 later when the SM is physically powered down, the registration state remains. Or if the SM was powered back up for any reason in a different location after the deregistration operation, it would have reused it’s stored CBRS CPI parameters. Let me know if you think this is a possibility. Or, if you can provide me with the MAC address for one of these such devices, I can try to check the SAS logs. Let me know if you prefer not to put your MAC in this public chat and I can reach out via private chat.
From your message I assume that not only do I need to de-register the radio from CBRS, I also need to remove the CPI data from the radio in order to keep it from re-registering, even if it has been Deregistered from Maestro. One of the radios we were seeing come back multiple times was linked to an AP where we had to shift frequency several times due to SAS IAP; so that AP was rebooted a few times.
If the radio has been deregistered from Maestro, the DPV, and the SAS, but still has its CPI data, should we expect it come online?
Correct, you will need to remove CPI data from that radio in order to keep it from re-registering. There is a small section near the end of the Cambium CBRS Consolidated Procedures guide that describes removing CPI data from the radios for long term storage.
When you initially deregister your SM via cnMaestro, you can look at the HOME → Session Status tab on the parent AP and you will notice that the AP has picked up the deregistration state and a deregister checkbox will be set in the session status table for that SM. This will prevent the SM from re-registering until the next AP reset. But if/when the AP is reset at any point in the future prior to you deleting the CPI data from the SM, that deregister flag can get cleared and the SM will re-register. Of course powering down the radio and physically removing it will also prevent such re-registrations, but it’s best practice to remove the CPI data anyway before power down, because if you redeploy the SM at a new site without having removed the CPI data, it will re-register using the old stale GPS coordinates.