A communication network comprises a head-end and a plurality of network terminations coupled thereto through a shared communication channel, which is accessed by a protocol having one or more dedicated slots wherein upstream data cells are contained, which may collide in a transmission wherein two or more network terminations try to access the shared communication channel practically simultaneously. Herein the protocol is arranged such that the one or more dedicated slots precede the moment whereon the first next downstream transmission is started to be prepared by the head-end. In that case actual information in the dedicated slots can be fed back without substantial delay to the network terminations in order to provide them by return with actual contention information.