TCP-IP CRC calculation in PCs

Hi, 
just a silly Q we are discussing here. The CRC calculation for TCP-IP
Protcols: Where is it calculated? In the CPU or the network-card?

Thanks
Michael
-- 
Remove the sport from my address to obtain email
www.enertex.de - Innovative Systeml�sungen der Energie- und Elektrotechnik

Michael Schuster wrote:
> Hi, 
> just a silly Q we are discussing here. The CRC calculation for TCP-IP
> Protcols: Where is it calculated? In the CPU or the network-card?
> 
> Thanks
> Michael

TCP/IP doesn't use CRC (Cyclic Redundancy Check), but a much easier to 
calculate 1's complement checksum. It is often calculated by the CPU, 
although there are also network cards that can do it. On common 
architectures, the calculation takes < 1 cycle/byte.

The Ethernet level CRC-32 is (nearly) always done by the netword card.

On Jan 9, 11:58=A0am, Michael Schuster <schusterSoc...@enertex.de>
wrote:
> Hi,
> just a silly Q we are discussing here. The CRC calculation for TCP-IP
> Protcols: Where is it calculated? In the CPU or the network-card?

Can be either, depending on the "checksum offload" setting of the
driver.  Some NICs may not support checksum offload, but these now
seem to be in the minority.

>
> Thanks
> Michael
> --
> Remove the sport from my address to obtain emailwww.enertex.de- Innovative=
 Systeml=F6sungen der Energie- und Elektrotechnik