Performance evaluation of the DOCSIS 1.1 MAC protocol according to the structure of a MAP message

In the Data Over Cable Service Interface Specification (DOCSIS) RFI v1.1, the control message, called MAP, is used to schedule the uplink radio frequency between the cable modem (CM) and the cable modem termination system (CMTS). We find out the appropriate MAP size and the optimum ratio between contention slots and grant slots in a MAP through computer simulations. To assess the performance of DOCSIS RFI v1.1 the Common Simulation Framework (CSF) is used. According to the simulation results the throughput and delay show best performance and the best choice for the number of contention slots may be six when the MAP size is 2 msec. The goodput for the upstream channel capacity is found to be about 58%.