Optical Network Control: Architecture, Protocols, and Standards

4.5. Summary

Table 4-13 summarizes the survivability options discussed in this chapter. It can be seen from this table that network survivability techniques involve a multidimensional trade-off between restoration time, bandwidth efficiency, and failure robustness.

Table 4-13. Properties of Protection/Restoration Methods

Name	Restoration Time	Bandwidth Required	Failure Robustness
1+1 Linear (SDH/SONET)	Typically under 50 ms	2x	Only as good as the diversity of the alternative paths. Handles single failure.
1:N Linear (SDH/SONET)	Typically under 50 ms		Only as good as the diversity of the paths, Handles single failure.
Bi-directional Line Switched Ring (BLSR) Failures.	Typically under 100 ms	2x	Diversity built in, one line out, except in 4F case which can handle ...