The Bit Interleaved Parity 8 is an error checking code
applied for quick isolation of faults. Each bit in the
B octets is set to 1 or 0 as necessary to obtain even
parity over the previous frame.
The calculated BIP-8 code for frame N is compared with
the BIP-8 code extracted from the B3 byte of frame N+1.
Differences indicate that a Path level bit error has
occurred.
Count of Path BIP-8 (Bit Interleaved Parity) errors that
have been detected on this phy.