Several operators are charged per megabyte of data by their ISP. In most cases there seems to be a discrepancy between what the ISP claims to have delivered and what the hotspot claims to have delivered. (hotspot is always measuring less than the ISP claims)
How is this possible?
User’s data transfer is measured after successful login, so non-login splash page loads will NOT be added to any user’s usage
There can be internal usage on the LAN port
Master accounts can also consume lots of data
There can be some data that is not recorded, because the router experienced a restart during sessions. The worst case scenario is that the usage of the last 100 seconds are lost per user, because the router sends accounting information to our servers in every 100 seconds.
There are interim accounting updates in every 100 seconds. The router is communicating to our servers to record data usage fro users. This can add a few bytes data transfers in every 100 seconds per user.
What can you do about this?
Check the usage of master accounts
Check the connections on the router maybe you can see some strange connections
You can change UAM Any DNS from 1 to 0 on dd-wrt’s hotspot section to avoid external DNS server usage of your users