Techniques are disclosed relating to a split communications fabric topology. In some embodiments, an apparatus includes a communications fabric structure with multiple fabric units. The fabric units may be configured to arbitrate among control packets of different messages. In some embodiments, a processing element is configured to generate a message that includes a control packet and one or more data packets. In some embodiments, the processing element is configured to transmit the control packet to a destination processing element (e.g., a memory controller) via the communications fabric structure and transmit the data packets to a data buffer. In some embodiments, the destination processing element is configured to retrieve the data packets from the data buffer in response to receiving the control packet via the hierarchical fabric structure. In these embodiments, bypassing the fabric structure for data packets may reduce power consumption.