Experimental evaluation of DOCSIS 1.1 upstream performance

Data-Over-Cable Service Interface Specification (DOCSIS) is one of the many last mile technologies intended to provide Internet access and packet-based services to the customer. DOCSIS uses the widely deployed hybrid fiber/coax (HFC) network as the physical link between multiple cable modems (CMs) and the cable modem termination system (CMTS). This paper presents the upstream performance of DOCSIS 1.1 in the physical layer and MAC layer across various traffic patterns. The experiments are conducted on real devices and not simulators as used in all previous research. The use of real devices allows us to capture the complete complexity of the protocol, and gives us realistic results but it also limits our control over different parameters. The goal of the project is to study the impact of different parameters that can be controlled by the cable service provider and to compare different CMs with respect to upstream performance. The performance metrics used are upstream data rate and channel utilization. The results can be used by the cable operators to optimize their networks, by the CM and CMTS manufacturers to enhance their products and they may help in identifying protocol bottlenecks for upstream performance.