System and methods for transmitting packets over a network are provided. A system includes a network access coordinator (NAC) configured to communicate with first and second nodes via a network backbone. The NAC is configured to coordinate access of the first and second nodes to the network backbone. The NAC is configured to receive, from the first node in a first time period, a first reservation request to transmit a first packet to the second node. The NAC is configured to allocate, in response to the first reservation request, a first slot in a second time period for the first node to transmit the first packet to the second node. The NAC is configured to allocate a second slot for the second node to transmit, to the first node, a first reply that includes an indicator of whether the second node received the first packet.