This read-only Integer32 reports the number of SONET Path-layer Byte Interleaved Parity errors detected on this OC-3 port during the current 15-minute period. It gives an administrator a path-layer signal-quality indicator, the most granular of the three BIP counters, useful for isolating problems to a specific virtual tributary. For example, an operator seeing path errors but not line or section errors would suspect a problem specific to the payload mapping rather than the physical optical transmission.