For many regional ISPs the most common outage is not a failed card but a cut fiber: road works, a falling pole, rodents or cable theft. Without protection, the route stays down until a crew finds the break and splices it, which can take hours. Optical line protection (OLP) moves the traffic to a second fiber path automatically, so the customers do not notice the cut.
How OLP works
- OLP 1+1: the signal is split and sent over both fiber paths at the same time. The receiving end monitors optical power on both and selects the good one, so switch-over needs no coordination between the two ends.
- OLP 1:1: traffic uses the working path, and both ends switch to the standby path when the working path fails. The standby path carries no traffic in normal operation.
- The OLP units in our catalog document 1:1, 1+1, 1-1 and BIDI modes, manual and automatic operation, and real-time optical power monitoring.
The rule that matters most: two separate paths
Protection only works if one event cannot cut both fibers. Two fibers in the same cable, or two cables on the same poles, will fail together. Plan the standby path over a different route, even if it is longer, and check that its loss still fits the optical budget of your transceivers or line system.
Find the break faster with OTDR monitoring
OLP keeps the service up; the cut still has to be repaired. An embedded OTDR card tests the fiber and shows the distance to the fault, so the crew goes straight to the right place. The DCI5800 OTDR card works at 1625 nm ±10 nm, outside the C-band used by DWDM traffic, with a 30–40 dB dynamic range and polling in eight directions.
1+1 or 1:1?
OLP 1+1 is the simpler choice for most point-to-point routes: each end decides on its own, so the configuration is easy to operate. It costs part of the optical budget, because the transmit signal is split over both paths. OLP 1:1 keeps the full signal on one path at a time, which helps on long routes where every decibel counts, but both ends must switch together. If you are not sure, send us both path losses and we will recommend the mode.
What to send us
The length and measured loss of both fiber paths, the equipment at each end (transceivers or a DWDM system), and whether you need one route or several. We reply within 24 hours with a configuration.