BIP-8 is an abbreviation for bit-interlaced parity 8 (alternatively BIP8). In a transmission transport system, BIP-8 consists of a bit byte computed on a large number of bytes. In the SONET / SDH and OPT Network standards, BIP-8 bits also have parity, like the Byte BIP-8. The BIP-8 is used in some older PDH-framing systems like DS3 or E3.
BIP-8 does not provide an error correction functionality: it has an estimated way to track the link output at the bit error stage, like the CRC-6 bits in a much older expanded super frame format.