Patent EA-003797-B1 (EA)
Title: Method and system for communication protection
Inventor: MARMUR OREN
IPC: H04B10/00
Filed: 2000-11-02
Abstract: 1. A method for diverting communication traffic in an optical transport network which comprises a first optical transmission link and a first optical reception link extending between a first and a second locations and carrying traffic in normal operation mode from the first location to the second location, and a second transmission link and a second reception link adapted to carry traffic diverted from the first optical transmission and reception links in the event of a fault in at least one of the two first optical links, which method comprises the steps of: detecting a fault on a first optical link at the second location; determining whether a total of the energy received over the first reception optical link at the second location exceeds a pre-defined threshold; in the case that the total energy thus received does not exceed the pre-defined threshold, diverting the traffic transmission and reception at the second location to the corresponding second links; detecting a fault on a first optical link at the first location determining whether a total of the energy received via the first optical link at the first location exceeds a pre-defined threshold; and in the case that the total energy thus received does not exceed the pre-defined threshold, diverting the traffic transmission and reception at the first location to the corresponding second links. 2. A method according to claim 1, characterized in that further comprising monitoring the operability of at least one of the second transmission path and the second reception path when, at least one of the second transmission path and the second reception path is not used for transmission of traffic during normal operation mode. 3. A method according to claim 1, characterized in that said second transmission path and second reception path extend between first and second locations via third location, and wherein each detection step is carried out during a pre-defined time, if total of the energy received exceeds a pre-defined threshold. 4. A method according to claim 1, characterized in that the pre-defined time is about 10 ms or less. 5. A method for routing traffic to a protection channel in an optical communication network which comprises a plurality of telecommunication channels extending between first and second locations, the telecommunication channels comprising a plurality of channels for carrying traffic in normal operation mode from the first location to the second location and at least one protection channel for carrying traffic in the event of a fault in at least one of the channels carrying traffic in normal operation mode, which method comprises the steps of: detecting a fault on at least one of the channels carrying traffic in normal operation mode, at the second location; switching at the second location the transmission and reception paths associated with said at least one failing channel to the at least one protection channel; detecting a fault on said at least one channel at the first location; and switching at the first location the transmission and reception paths associated with said at least one failing channel to the at least one protection channel. 6. A method according to Claim 5, wherein said at least one protection channel is used for protecting at least one pre-designated channel out of the plurality of telecommunication channels. 7. A method according to Claim 5, wherein said at least one protection channel is used for protecting a plurality of telecommunication channels. 8. An optical communication system comprising a plurality of telecommunication channels extending between first and second locations, the channels comprising a plurality of forward channels for carrying traffic in normal operating mode from the first location to the second location, at least one protection link for carrying the traffic of at least one of said forward channels in the event of fault in said at least one forward channel, wherein in response to a detection of loss of signal in said at least one forward channel, traffic designated to be transmitted along said at least one forward channel is diverted to said at least one protection link at each of the first and second locations, independent of detecting a loss of signal at the other of said first and second location. 9. An optical communication system according to Claim 8, further comprising means adapted to monitor the operability of the protection link during normal operation mode of the system.