Troubleshooting- The PTP450i Link drops everyday at the same time.


The PTP450i Link drops (every 24 hours) for a while every day at the same time.


We will have to check and follow the below points to verify and resolve the issue.

Please check the below steps in order to fix the issue:

  • Confirm the date and time of the issue.
  • Check the disconnection date and time in the debug logs (VCerror: Session) and verify if it follows the 24 hours pattern.
  • Check if the radios are configured with AES/DES encryption on the home page of the PTP450i radios
  • Please login to the PTP450i BHM and navigate to, Configuration>>>Security, to see if the Airlink security is enabled or disabled.
  • We will have to disable the “24 hours encryption refresh” which will resolve the issue. (Refer the below screenshot).


  1. An over-the-air link encryption option uses the Rijndael algorithm and 128-bit keys to establish a higher level of security than DES. If we select 24 hours encryption, then the radio will allow BHS re-registration every 24 hours, as it changes the encryption bits (not the key) after every 24 hours to ensure high level of security.
  1. By default, Air link security is disabled.
  1. From system release 15.2, support for DES has been dropped. Considering a scenario where an SM was configured to run DES and then upgraded to system release 15.2, it would still be configured to run DES but not capable of running DES. Now, with system release 15.2.1, if the SM is set to DES but is also capable of running AES, it will automatically be set to run AES. This way, if the AP is set to None or AES, the SM will register and use the encryption setting specified by the AP. Note that if the AP is running a system release prior to 15.2 and is still set to DES, then the SM running 15.2 or later will not register to it as it no longer supports DES.
1 Like