An interface unit may comprise a buffer configured to store requests that are to be transmitted on an interconnect and a control unit coupled to the buffer. In one embodiment, the control unit is coupled to receive a retry response from the interconnect during a response phase of a first transaction for a first request stored in the buffer. The control unit is configured to record an identifier supplied on the interconnect with the retry response that identifies a second transaction that is in progress on the interconnect. The control unit is configured to inhibit reinitiation of the first transaction at least until detecting a second transmission of the identifier. In another embodiment, the control unit is configured to assert a retry response during a response phase of a first transaction responsive to a snoop hit of the first transaction on a first request stored in the buffer for which a second transaction is in progress on the interconnect. The control unit is further configured to provide an identifier of the second transaction with the retry response.