This topic describes the three-way protection topology formed by combining section and path protection, including threshold recommendations and limitations for switching behavior.
NCS 1001 supports PSM three-way protection scheme formed by combining a section protection scheme with a path protection scheme. No configuration change is required in PSM to implement the three-way protection scheme. The path protection scheme is inserted into one of the two paths in the section protection scheme.
Topology
Use the PSM automatic threshold configuration for the outer section protection.
Limitations
The three-way protection scheme has these limitations:
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For each PSM, switching the bi-directionality is not definite.
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Manual switching used to change the active path is sometimes unsuccessful.
Apply the lockout configuration on all four PSMs of the protection scheme to control switching from one path to another. Apply the lockout configuration on both the local and the corresponding remote PSM to ensure bi-directionality.