Patent ID: 9525507
Filing Date: 2016-12-20
CPC Classification: H04J,H04Q

Claim Text:
1. A method of tuning a wavelength in a time and wavelength division multiplexing-passive optical network (TWDM-PON) having a plurality of operable channels, the method comprising operations of: (a) after a second channel is added as an operating channel of the TWDM-PON in which at least a first channel is working, sending a wavelength tuning request message from an optical line terminal (OLT), which is providing a service to an optical network unit (ONU) through the first channel, to request the ONU to change from the first channel to the second channel; (b) in response to receiving the wavelength tuning request message, determining, at the ONU, whether or not a downstream wavelength of the second channel has been recorded on the ONU; and (c) in response to a determination that the downstream wavelength of the second channel is recorded on the ONU, sending to the OLT an ACK message that indicates that the ONU is able to perform wavelength tuning, and then commencing wavelength tuning to the second channel, and in response to a determination that the downstream wavelength of the second channel is not recorded on the ONU, sending to the OLT a NACK message that indicates that the ONU is unable to perform wavelength tuning.