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 B1 byte of frame N+1. Differences indicate that
a section level bit error has occurred.
Count of Section BIP-8 (Bit Interleaved Parity) errors
that have been detected on this phy.