Based on the receive modulation error ratio (RxMER) values collected periodically during upstream probing, the CMTS finds
among the existing IUCs up to two that provide the highest speed while having sufficient signal to noise ratio (SNR) margin
for the CMTS to receive code words with acceptable error rates. The show cable modem phy ofdm-profile upstream command displays the one or two recommended IUCs for each CM.
In Cisco IOS XE Everest 16.6.1 release, data IUC 13 will be one of the IUCs assigned to the CM.
To disable the automatic profile downgrade, use no cable upstream ofdma-prof-mgmt prof-upgrade-auto command in global configuration mode.