During the IESG review, there were a few comments raised about the use of the 
MAC Address in the X.509 certificate Common Name (CN) field. There were two 
agreements made during this time, the first was to provide references to other 
standards that were making use of this convention (e.g., Packet Cable, WiMAX, 
DOCSIS). The second was to include some text about the reasoning for using the 
MAC Address in the CN Field vs. some other (more appropriate) identifier.