A cable communication system includes one or more data-plane virtual network functions (VNFs) and one or more control-plane VNFs. The data-plane VNFs are configured to run on one or more hosts in a data network, and to perform data-plane medium access control (MAC) processing for a plurality of user-side cable modems and for a plurality of network-side physical-layer (PHY) devices that communicate with the user-side modems. The control-plane VNFs are configured to run on at least one host in the data network, separately from the data-plane VNFs, and to perform control-plane processing for the user-side modems and the network-side PHY devices.