ISP networks

Optical fiber link security protection method and device

OLP is an automatic monitoring and protection system that is completely independent of the communication transmission system and is completely established on the physical link of the optical cable. When the working optical fiber loss increases and the communication quality is degraded or the working optical fiber is blocked, the system can automatically switch the optical communication transmission system from the working optical fiber to the standby optical fiber in real time, restore communication, and realize synchronous switching protection of the optical cable line, thereby greatly improving The availability of fiber optic cable lines enhances the reliability of the communication system and guarantees service quality. The OLP adopts the 1:1 selection and selection protection mode--the working service signals are transmitted along the working optical fiber, and the non-working optical fiber can send the secondary first-level service signal. The OLP devices at both ends synchronously select to work on the primary fiber or switch to the backup fiber according to the status of the primary fiber and the backup fiber.

At present, the OLP system is widely used in the trunk transmission network. In the implementation and maintenance of the OLP, the following matters should be noted: (1) The intervention of the OLP will increase the loss of the system, and the redundancy of the system and whether there is dimming need to be considered. Decline and other specific circumstances. (2) When the main/standby cable type is the same, the OLP system is switched, and the performance and data services of the DWDM/SDH system can be quickly restored to normal. (3) When the main/standby optical cable type is different, if the suitable dispersion compensation module is not added, after the OLP system is switched, the optical power is normal for the DWDM/SDH system, but the data service cannot be restored. (4) When the optical cable cutover is required during the maintenance process, the OLP configuration mode is normally not returning to the automatic mode. Before the cable break operation, the system primary and backup conditions must be checked first. Manually forcibly switch to an alternate route. (5) If the system fails to work properly after the OLP is connected, or the OLP cannot be switched normally, the system must be restored to the original state within the time range of the cutover to ensure that the system services are not affected. OLP system is a good supplement to the security of the trunk optical transmission network because of its simple system, small impact on the original system, good compatibility with various transmission equipment, and real-time monitoring. Protection also has very positive practical value, enabling ISPs to simplify network management and maintenance.