The particularity of optical transmission network requires that the optical transmission lines and optical transmission equipment must have high reliability. The security of optical transmission network has become the core of operators at all levels.
However, in current networks, problems such as optical fiber damage, line interruption, equipment power down as well as board fault and so on would seriously affect the stability of the transmission network, which causes service interruption to customers, businesses and effects operators SLAs putting pressure on technical personnel. Therefore, it is critical to have a strong protection mechanism in place for the network.
Sino-Telecom’s OLP system can provide real-time monitoring of the primary and secondary optical fibers, which effectively avoid the simultaneous block of the two optical fibers. In the event of a signal loss or low signal level below a threshold value on the main fiber l, the system will automatically switch to the secondary available optical fiber also called backup route, so as to ensure the smooth flow of the service.
Sino-Telecom’s OLP system includes different protection modes of 1:1, 1+1, BIDI and BP, which can meet requirements of different application scenarios.
(1) OLP 1：1
OLP 1:1 adopts the mode of selective transmitting and selective receiving. The key features are small insertion loss, fast switching and support for monitoring of the secondary line. It can be mainly applicable to the trunk/local transmission network and customers of private lines.
(2) OLP 1+1
OLP1+1 adopts the mode of dual transmitting and selective receiving. The key features are fast switching, low cost, but large insertion loss. It is applicable to short-distance customers with large surplus of the line.
(3) OLP BIDI
The working mode of BIDI is dual transmitting and selective receiving. Optical line protection is realized by ways of bidirectional transmission over single optical fiber. It is mainly applicable to scenarios when there are limited amount optical fiber resources.
(4) OLP BP
OLP BP is a bypass protection device, which is mainly used to protect cascade device. When there is no optical signal of the device or power down occurs, it will automatically bypass the device, so as to ensure the normal communication.
Sino-Telecom’s OLP BP device is with the features of small insertion loss and fast switching.
Sino-Telecom’s OLP system has been widely applied in optical transmission network of China Mobile and of many other foreign operators.
(1) China Mobile Sichuan Branch 10G SDH Optical Protection Solution
Bearer Service: Single channel of 10G SDH
In the original line, 40KM dispersion+PA has been compensated. The attenuation is large, therefore, BA are added at the two ends.
(2) Bangladesh Telecom DWDM 1+1+1 Optical Line Protection
Bearer Service: 12*10G, 6*2G5
In this scheme, 12 channels of 10G and 6 channels of 2G5 Dhaka--6 sites in Cox‘sBaza--600KM bidirectional transmission of 18 channels of services are realized. 1+1+1 protection by 3 optical lines are made (Note: only part of the sites are shown the figure).