RADIUS accounting counters are wrong?

Hi!

RouterOS 2.9.40, freeradius 1.0.2 (Debian Sarge)

We’re using mikrotik as NAS (pptp server) and for RADIUS accounting.

There are some differences within windows counters (interface status) and mikrotik radius accounting counters:

for example windows shows that i’m received 11110604 bytes, but mikrotik shows that i’m received 11070855 bytes (Acct-Output-Octets). Is mikrotik counters are wrong? Or if there any other reason why counters data are differ? (in the case of linux+pptpd counters are identical).

Thanks.

Radius aren’t updated in real time… It only updates every x amount of seconds as specified by the Acct-Interm-Update interval.

i’m understand, but overall results in radius and windows are differ after session ends (usually mikrotik counts less traffic than windows) and difference is growing if user transfers large amount of data through VPN.

Maybe windows counts encapsulated length, and mikrotik reports just data going through VPN interface?