A node comprises an interconnect, circuitry coupled to the interconnect and configured to initiate a transaction on the interconnect, and a control circuit coupled to provide a response to the transaction on the interconnect. The transaction addresses a block, and the response is indicative of a state of the block in one or more other nodes. The control circuit is configured to cause the transaction to become globally visible to the one or more other nodes dependent on the state in the one or more nodes. Using one or more communication lines separate from lines used to initiate transactions, the control circuit is configured to transmit an indication of the transaction on the interconnect responsive to the transaction becoming globally visible. A transfer of data on the interconnect for the transaction is delayed, responsive to the response from the control circuit, until the indication is transmitted by the control circuit.