00-1C-23-59-5A-92
, 001c23595a92
, 00:1C:23:59:5A:92
001c
, 2359:92
-
) or colons (:
), in transmission order (e.g. 01-23-45-67-89-ab
or 01:23:45:67:89:ab
). This form is also commonly used for EUI-64. Another convention used by networking equipment uses three groups of four hexadecimal digits separated by dots (.
) (e.g. 0123.4567.89ab
), again in transmission order.FF:FF:FF:FF:FF:FF
. A broadcast frame is flooded and is forwarded to and accepted by all other nodes.FF-FF
and then copy the organization-specified extension identifier. To convert an EUI-48 into an EUI-64, the same process is used, but the sequence inserted is FF-FE
. In both cases, the process can be trivially reversed when necessary. Organizations issuing EUI-64s are cautioned against issuing identifiers that could be confused with these forms. The IEEE policy is to discourage new uses of 48-bit identifiers in favor of the EUI-64 system.FF-FE
(and never FF-FF
) and with the U/L bit inverted.12-34-56-78-9A-BC
would be transmitted over the wire as bits 01001000 00101100 01101010 00011110 01011001 00111101
in the standard transmission order (least significant bit first). But for Token Ring networks, it would be transmitted as bits 00010010 00110100 01010110 01111000 10011010 10111100
in most-significant-bit first order. The latter might be incorrectly displayed as 48-2C-6A-1E-59-3D
. This is referred to as bit-reversed order, non-canonical form, MSB format, IBM format, or Token Ring format, as explained in RFC 2469. Canonical form is generally preferred, and used by all modern implementations.