when it has been executed by the slave as there is no response message to the master no guarantee regarding transaction completion can be given a transaction with a response e g an acknowledged write is said to be complete when a retstat message is received from the anip recall that when data is received as a response retdata a retstat possibly implicit is also received to validate the data the transaction may either be executed successfully in which case a success retstat is returned fail in its execution at the slave and then an execution error retstat is returned or fail because of buffer overflow in a connection with no flow control and then it reports an overflow error we assume that when a slave accepts a cmd requesting a response the slave s always generates the response the dropping manager dm may drop data in case of buffer overflow all of cmd outdata and retdata may be dropped to guarantee transaction completion retstat is not allowed to be dropped consequently in the anips enough buffer space must be provided to accommodate retstat messages for all outstanding transactions this is enforced by bounding the number of outstanding transactions for the case of several slaves s in the above system return message or response messages could be combined as follows if each of write transaction initiated by the master m has been successfully executed by all slaves s all will return retstat retok messages which can be combined by the anip.