Patent ID: 8179879

Claim:
In a passive optical network in which data is transferred by packets, a ranging method comprising the steps of: by an optical line terminal: a. After start of a ranging window, periodically comparing received data with expected data to find a match therebetween, by steps including: i. searching an incoming data stream for a known packet preamble until the preamble is found or until a first timeout is exceeded, wherein the exceeding of the first timeout represents a first match failure, and ii. if the preamble is found, searching the incoming data stream for a known packet delimiter until the delimiter is found or until a second timeout is exceeded, wherein the exceeding of the second timeout represents a second match failure; b. in case of a match failure, restarting the comparison within the same ranging window until a match is found; and c. if a match is found, moving to a steady state operation regime; wherein the step of periodically comparing ends in a match failure and wherein the step of restarting includes restarting the comparing until a global timeout is exceeded.