This paper provides a brief introduction to adaptive bit rate (ABR) video and discusses why handling this class of traffic well is very important to the cable operator. It then examines the major differences between ABR and the current IP and MPEG video delivery mechanisms and looks at the impact these differences have on the network. Some interesting experimental results observed with real world ABR clients are presented. A number of problems which may develop in the network as ABR clients are deployed are discussed and possible solutions for these proposed. Finally, the paper looks at the cable modem termination system (CMTS) as a potential control point that could be used to mitigate the impact of the ABR clients and regain control of the access network for the operator.