Final answer:
The Cable Modem Termination System (CMTS) uses the MAC layer of the DOCSIS protocol to differentiate between cable modems.
Step-by-step explanation:
The Cable Modem Termination System (CMTS) uses the MAC (Media Access Control) layer of the DOCSIS (Data over Cable Service Interface Specification) protocol to differentiate between cable modems. The MAC layer is responsible for managing access to the shared cable medium and ensuring that each cable modem gets its fair share of bandwidth.
At the MAC layer, each cable modem is assigned a unique MAC address, which is used to identify and differentiate between the cable modems connected to the CMTS. This allows the CMTS to communicate with each cable modem individually and provide the appropriate network services.