1+1 APS configuration example

Overview

Figure 38-1, Normal operations between two 7750 SRsand Figure 38-4, Normal operations resume on the protection line show an example of 1+1 APS for two 7750 SRs that are configured for 1+1 APS in bidirectional and non-revertive modes.

Figure 38-1, Normal operations between two 7750 SRs shows normal operations between two 7750 SRs. There are no faults on the working line, and the protection line is not in use.

Figure 38-1: Normal operations between two 7750 SRs

The working line degrades in the direction from site A to site B. Site B detects the fault and notifies site A of the fault using the protection line. The following figure shows the fault on the working line and site B notifying site A of the fault.

Figure 38-2: Site B detects the fault and notifies site A

Site B automatically switches to the protection line. Site A receives the fault notification from site B and detects the fault on the working line. Site A acknowledges the fault and notifies site B that it is switching to the protection line. The following figure shows site B switching to the protection line and site A acknowledging the fault.

Figure 38-3: Site B switches to the protection line and site A acknowledges the fault

Site B receives the notification from site A and site A automatically switches to the protection line. The following figure shows normal operations resuming on the protection line between site A and site B. The protection line becomes and remains the working line since 1+1 APS is configured for non-revertive switching in this example.

Figure 38-4: Normal operations resume on the protection line