I just recently noticed something interesting. I'm generating my config files using the open source docsis program that's on sourceforge. Recently a customer started complaining that his speeds were not running as high as they should, so i started looking at his modem to make sure it had the correct provisioning.
Through snmp, I can see that he is getting the correct config file, but I also see this:
IF-MIB::ifType.1 = INTEGER: ethernetCsmacd(6)
IF-MIB::ifType.2 = INTEGER: docsCableMaclayer(127)
IF-MIB::ifType.3 = INTEGER: docsCableDownstream(128)