An access point that supports downstream and upstream communication from and to a Modular Cable Modem Termination System (M-CMTS) core to and from customer premises equipment (CPE), respectively, implements an Upstream External PHY Interface (UEPI) protocol with the M-CMTS core for control of the upstream communication. The access point receives from the M-CMTS core first UEPI control messages comprising information to configure one or more pathways with the access point for data plane upstream communication and control plane communication. The access point transmits to the M-CMTS core second UEPI control messages including a spectrum management message to manage upstream spectrum between the access point and the M-CMTS core, and a range request message to request ranging information so that the CPE can transmit upstream packets within an upstream timeslot, wherein at least one second UEPI control message is forwarded from the (CPE).