The IEEE likes to specify numbers in bit transmission order, or bit- wise little-endian order. The Internet protocols are documented in byte-wise big-endian order. This may cause some confusion about the proper values to use for numbers. Here are the conversions for some numbers of interest.
Number IEEE IEEE Internet Internet
HEX Binary Binary Decimal
UI Op Code C0 11000000 00000011 3
SAP for SNAP 55 01010101 10101010 170
XID F5 11110101 10101111 175
XID FD 11111101 10111111 191
TEST C7 11000111 11100011 227
TEST CF 11001111 11110011 243
Info 818000 129.1.0