How the kernel receives packets?

How the kernel receives packets?
quoted from : Professional linux kernel architecture by Wolfgang Mauerer, page 760.

1. packets arrives at the kernel at unpredictable times. All modern device drivers use interrupts to inform the kernel ( or the system) of the arrival of a packet.

2. The network driver installs a handler routine for the device-spefic interrupt so that each time an interrupt is raised--whenever a packet arrives-- the kernel invokes the handler function to transfer the data fro the network card into RAM, or to notify the kernel to do this some time later .

3. Nearly all card support DMA mode and are able to transfer data to RAM automatically.

4 However, these data needs to be interpreted and processed, and this is only performed later.

Understanding Linux Network Internals
By Christian Benvenuti
http://book.chinaunix.net/special/ebook/oreilly/Understanding_Linux_Network_Internals/0596002556/toc.html


黃毓民@政改表決動議辯論--PT.1
http://www.youtube.com/watch?v=yGcIF9gbdM8&feature=youtube_gdata

黃毓民@政改表決動議辯論--PT.2
http://www.youtube.com/watch?v=Ee7ddhyKBpE&feature=youtube_gdata