Moving to a new OLT management system without customer downtime
Many ISPs stay on a system they don't like because they fear the move. That fear is reasonable: a careless migration can take thousands of customers offline. Done in the right order it is invisible to customers. This is the order we use.
1. Watch first, change nothing
Connect the new system to one OLT in read-only mode, next to your current one. Compare ONT counts, status and signal for a few days. If the numbers don't match, stop and find out why.
2. Bring your data across
Names, addresses, contacts, zones, splitters and PPPoE usernames often exist only in the old panel. Import them and check them against what is really on the OLT.
3. Test every ONT model
Pick one online customer of each model and firmware and move only that ONT. Check that the internet, management and Wi-Fi settings still work. Some models behave differently; you want to learn that on one customer, not on five hundred.
4. Move in waves
Move one PON, then a few, then a board, then the rest. Check each wave before starting the next. Good tooling checks every ONT after its change and undoes it automatically if it doesn't come back.
5. Handle the stragglers
ONTs that were offline during the waves are moved when they come back online. Third-party routers with unusual settings are done one at a time, with the customer's details at hand.
6. Clean up
Once every ONT is moved, remove the old system's leftovers from the OLT, take a configuration backup before and after, and switch the old system off.