what's the state a packet in when a sending complete interrupt happens?

Hi all:
     I am doing the overhead analysis for UDP/IP over ethernet. My testing Network controler is 82559. I meet some problem when I reading the driver source code (eepro100.c) in Linux kernel 2.2.17

    I describe the question as follows: 

In function "speedo_start_xmit", If an sending entry's is marked as CmdIntr, the controler will produce an interrupt when this packet sending complete. My question is what is the means of complete? Is it means that the packet has been successfully put into the  ethernet OR just be copied from host memory into NIC send buffer?

   Could you tell me something about it?

thanks a lot!

Gang Shi
e-mail: [email protected]
Division of Computer Architecture
Institute of Computing Technology
Chinese Academy of Sciences
P.O.Box  : 2704-25 Beijing, China
Post Code: 100080