The Bit Interleaved Parity 8/24 is an error checking code
based on even parity. The calculated BIP code for frame N
is compared with the BIP-8/24 code extracted from the B2
byte(s) of frame N+1. Any differences indicate that a
line layer bit error has occurred.
Count of line bit interleaved partiy (BIP-8/24) errors on
this phy.