Method and apparatus for automatically upgrading passive optical networks (PONs)
An apparatus automatically maintains bi-directional communication between an optical network unit (ONU) and a central office (CO) in a passive optical network (PON) when the CO changes from a first PON mode to a second PON mode. The apparatus senses a PON mode relating to downstream data flow from the CO to the ONU; and upon detecting a change in the PON mode from the first PON mode to the second PON mode, synchronizes the ONU to operate according to the downstream and upstream configurations of the second PON mode.
1. A method for automatically maintaining bi-directional communication between an optical network unit (ONU) and a central office (CO) in a passive optical network (PON) when the CO upgrades from a first optical line terminal (OLT) having a first PON mode to a second OLT having a second PON mode, the method comprising:
obtaining a PON mode relating to downstream data flow from the OLT to the ONU; and
upon detecting a change in said PON mode from the first PON mode to the second PON mode:
synchronizing said ONU to operate according to a downstream configuration of the second PON mode by performing:
attempting to synchronize the ONU according to a last-known downstream configuration of the PON;
when the ONU is unsynchronized, attempting to try to connect again with a downstream configuration used prior to the last-known setting;
when the ONU is still unsynchronized, attempting to synchronize the ONU according to the line rates and line-codes that are pre-defined in the ONU; and
synchronizing said ONU to operate according to an upstream configuration of the second PON mode.
2. The method of claim 1 , wherein said first PON mode is a broadband PON (BPON) or an Ethernet PON (EPON).
3. The method of claim 2 , wherein said second PON mode is at least a Gigabit PON (GPON).
4. The method of claim 1 , wherein said first PON mode is an EPON or a GPON.
5. The method of claim 4 , wherein said second PON mode is a BPON.
6. The method of claim 1 , wherein said first PON mode is a BPON or a GPON.
7. The method of claim 6 , wherein said second PON mode is an EPON.
8. The method of claim 1 , wherein said downstream configuration comprises a line-code and a downstream line-rate.
9. The method of claim 8 , wherein retrieving said downstream configuration further comprises:
obtaining at each time one of the following: a last known configuration of the PON, a prior to last known configuration of the PON, a predefined standard configuration.
10. The method of claim 9 , wherein said ONU is synchronized if it is reaches a SYNC state as defined in the respective second PON mode.
11. The method of claim 10 , further comprising checking if said ONU reached the SYNC state prior to synchronizing said upstream configuration.
12. The method of claim 1 , wherein said upstream configuration comprises an upstream line-rate.
13. The method of claim 12 , including determining said upstream line-rate using a ranging process.
14. The method of claim 1 , further comprising generating an error message if said ONU fails to synchronize.
15. A program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform a method for automatically maintaining bi-directional communication between an optical network unit (ONU) and a central office (CO) in a passive optical network (PON) when the CO upgrades from a first optical line terminal (OLT) having a first PON mode to a second OLT having a second PON mode, the method comprising:
detecting a change in PON mode relating to downstream data flow from the CO to the ONU; and
synchronizing said ONU to operate according to a current downstream configuration by performing:
attempting to synchronize the ONU according to a last-known downstream configuration of the PON;
when the ONU is unsynchronized, attempting to try to connect again with a downstream configuration used prior to the last-known setting; and
when the ONU is still unsynchronized attempting to synchronize the ONU according to the line rates and line-codes that are pre-defined in the ONU; and
synchronizing said ONU to operate according and a current upstream configuration of the second PON mode.
16. The program storage device of claim 15 , wherein said first PON mode is a broadband PON (BPON) or an Ethernet PON (EPON).
17. The program storage device of claim 16 , wherein said second PON mode is a Gigabit PON (GPON).
18. The program storage device of claim 15 , wherein said first PON mode is an EPON or a GPON.
19. The program storage device of claim 18 , wherein said second PON mode is a BPON.
20. The program storage device of claim 15 , wherein said first PON mode is at BPON or a GPON.
21. The program storage device of claim 20 , wherein said second PON mode is an EPON.
22. The program storage device of claim 15 , wherein said downstream configuration comprises at least: a line-code, a downstream line-rate.
23. The program storage device of claim 15 , wherein the ONU is synchronized if a SYNC state is reached as defined in the respective second PON mode.
24. The program storage device of claim 23 , further including checking if the ONU reached the SYNC state prior to synchronizing said upstream configuration.
25. The program storage device of claim 15 , wherein said upstream configuration comprises an upstream line-rate an upstream line-rate.
26. The program storage device of claim 25 wherein said upstream line-rate is determined by a ranging process.
27. The program storage device of claim 15 , wherein said method further comprises generating an error message if said ONU is failed to synchronized.