iSCSI command numbering

[gabriel@sangate.com]

hi

when an iSCSI target recives task with CmdSN=X and decides to reject it because of internal queueing issues( e.g. queue is full...) 
what should the  target do when it sees the next task with CmdSN=X+1 ?
    a) accept it ( it saw CmdSN=X  so there are no flows in the network layer ) OR
    b) buffer it, waiting for task with CmdSN=X  to be resent( ensure total ordering on the tasks )

/gabi