450i SM in 450 Legacy Mode

Hey guys... I have a question

I have a PMP450i SM currently running on a regular 450AP... I get the following message

"PMP 450/430 Legacy Mode Enabled. Sector throughput will be limited."

What bothers me is that when I go to set a priority VC the amount of SM drops from the AP and re-registrations skyrocket. I removed the VC and the stability improved dramatically. In another similar situation that I could track I noticed the 450i SM has a higher session count than the other 450 sms on a normal 450 AP which is also significantly higher that the normal 450 SM that it replaced at the exact same location and mount.

Is this behavior to be expected when moving backwards?

Im trying to get any additional information on this from either posted documentation or other people's experience. I have had no issues with the PMP450 SMs on the PMP450i APs.


I would request you to please provide the CNUT captures from the AP and the SM. Please send me an email to vivek.gupta@cambiumnetworks.com so that I can get in touch with you offline regarding this issue.


Vivek Gupta

Cambium Technical Support Team

I just ran a test. I gathered support information while it was stable. 1 session for 5 days.

I then enabled the high priority channel under QOS and cleared the session count.

1 hour 30 minutes later it had re-registered to the tower 3 times.

I took another gather support info off the radio and forwarded it to support.

I noticed this time that the 2nd VC comes through as 1x. Is that intended?