A cable modem integrated session border controller operates as a point of demarcation between a local area network (LAN) and a DOCSIS network and, in response to receiving a Session Initiation Protocol (SIP) message, which includes Session Description Protocol (SDP), from a VoIP device coupled to the LAN, communicates with a Cable Modem Termination System (CMTS) to take advantage of DOCSIS Dynamic Quality of Service (DQoS). If required service flow attributes, as determined from the SDP of the SIP message, matches service flow attributes of an existing UGS service flow with a CMTS, a DOCSIS Dynamic Service Change (DSC) request is used to add an additional sub flow to the existing UGS service flow. If attributes fail to match attributes of all existing UGS service flows, a DOCSIS Dynamic Service Change (DSC) request is used to initiate an additional UGS service flow with the required service flow attributes.