Patent ID: 8953936
Filing Date: 2015-02-10
Classification: H04B,H04J

Abstract:
1. A method performed by an Optical Line Termination (OLT) system for protecting a plurality of OLT ports against failure without the use of a physical switch, the OLT system including a plurality of OLT ports for providing telecommunication services to a plurality of Optical Network Units (ONUs) in a Wavelength Division Multiplexing (WDM) Passive Optical Network (PON), the method comprising the steps of: detecting by the OLT system a failure of a first OLT port in the plurality of OLT ports, wherein the first OLT port was originally adapted to transmit downstream traffic to a first subset of ONUs in the plurality of ONUs on a first downstream wavelength and to receive upstream traffic from the first subset of ONUs on a first upstream wavelength, and wherein a protection port was originally adapted to transmit downstream traffic to a second subset of ONUs in the plurality of ONUs on a second downstream wavelength and to receive upstream traffic from the second subset of ONUs on a second upstream wavelength when not in service protecting one of the OLT ports, where the first downstream wavelength and the first upstream wavelength form a first wavelength set, and where the second downstream wavelength and the second upstream wavelength form a second wavelength set; informing the first subset of ONUs to tune to the second wavelength set used by the second subset of ONUs for transmission and reception, or informing the second subset of ONUs to tune the first wavelength set used by the first subset of ONUs for transmission and reception, upon detection of failure in the first OLT port; tuning the protection port of the OLT system to the first wavelength set for transmission and reception if the second subset of ONUs were informed to tune to the first wavelength set or keeping the protection port tuned to the second wavelength set for transmission and reception if the first subset of ONUs were informed to tune to the second wavelength set; and resuming communication between the OLT system and both the first subset of ONUs and the second subset of ONUs on a shared basis through the protection port.