SNP Message Trailer.........................................................................................................3-2 Data Bytes .........................................................................................................................3-3 Attach Message...........................................................................................................3-3 Attach CPU ID Field..................................................................................................3-4 Attach Master T1 Field ..............................................................................................3-4 Attach Message Example ...........................................................................................3-4 Attach Response .........................................................................................................3-5 Attach Response CPU ID Field..................................................................................3-6 Attach Response T1 Field ..........................................................................................3-6 Attach Response Example..........................................................................................3-6 Contents vi GFK-0529C Mailbox Message........................................................................................................3-7 Packet Number...........................................................................................................3-8 Initial Request Mailbox Messages .............................................................................3-8 Completion ACK Mailbox Messages ......................................................................3-10 Piggy-Back Status Information ................................................................................3-11 Control Program Number.........................................................................................3-11 Privilege Level ..................................