Difficulty establishing AP to SAS CBRS communication through a cnMaestro™ proxy on release PMP450 16.2.2

Document Number FSB9082
Revision 000v001
Download the PDF version Application Global
Effective Date Sept 29, 2020
Expiry Date N/A
  Warranty Service X High – Perform immediately
X Informational   Medium – Perform at next scheduled maintenance
  Customer Specific   Low – Perform when system exhibits symptoms

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SUBJECT: Difficulty establishing AP to SAS CBRS Communication through a cnMaestro™ proxy on PMP450 Release16.2.2

MODEL / SYSTEM AFFECTED: Any CBRS PMP450 AP operating on software release 16.2.2 while using an On-Premises cnMaestro configuration as an HTTP Proxy.

SYMPTOM: A critical issue has been observed in Release 16.2.2 with CBRS, where customers using cnMaestro On-Premises as an HTTP proxy frequently have difficulty in properly establishing the connection between the AP and cnMaestro proxy after an upgrade to 16.2.2 or a reboot of the AP. Although the problem is not seen consistently, it is frequent enough where Cambium does not recommend using 16.2.2, if operating cnMaestro On-Premises as an HTTP Proxy.

CURRENT STATUS OF INVESTIGATION: The issue has been isolated to a change introduced in the AP/BHM radio software in release 16.2.2 and confirmed to impact CBRS setups only.

RESOLUTION: Reconfigure CBRS setups to use an external HTTP proxy server instead of using their cnMaestro server as a proxy. Note that Cambium does not recommend using OnPremises cnMaestro but suggests an external proxy configuration – or configure the system without using a proxy if possible.

– Upgrade to the R20 BETA release for deployments where BETA loads are an acceptable solution. The R20 BETA release is currently available at
– Software Release 16.2.3 contains a fix for this issue and is expected to release mid October, 2020.

Software Release 20 will also contain this fix (among other new features) and is expected to be released late in October, 2020.

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