What are the Maximum SDH B1, B2, B3 or BIP-8 Error Rates for STM-N Signals?

There are mathematical limits to the rate at which Bit Interleaved Parity (BIP-X) checksums can accurately detect errors or be generated (not counting the thresholds that trigger higher level errors and alarms).


The B1 (BIP-8) in an STM-1 Regenerator Section Overhead (RSOH) that can accurately detect up to 4.11E-4 error rate, but its limits depend on the link's data rate. For example:

  • STM-1               4.11E-4
  • STM-4               1.37E-4
  • STM-16             3.43E-5


The Multiplex Section Overhead's (MSOH) B2 for an STM-N stream is based on BIP-Nx24 (e.g., BIP-24 for STM-1 and BIP-96 for STM-4) and it can accurately detect error rates up to 1.25E-3. This is independent of the data rate.


The maximum equivalent error rate that can be conveyed using this BIP-8 checksum for Path data, including the payload and the Path Overhead (POH), depends on the type of mapping being used. If VC-4 is used, then the mathematical limit on the maximum detectable B3 error rate is then 4.25E-4.

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