Messages in this thread | | | Date | Fri, 24 Aug 2001 10:01:51 +0200 | From | Helge Hafting <> | Subject | Re: hardware checksumming |
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Christian Widmer wrote:
> yes that might be easy for the NIC's transmitting enging when all fragments > belonging together come one after the other in the transmit-ring. > but receiving is difficult since different connections can arrive > simultanously and reslut in interleaved framgents. > > something else: you need quite a lot of ram on the NIC to buffer fragments. > if not it will have to transfer the data twice through the PCI (checksumm are > at the beginig of a packet not the end). nobody did spend a second on > thinking to implement all in hardware when the interet protokol was desinged.
You don't have to store entire fragments in a NIC to do hw checksums. All you need to store is the partial checksums, and add to them whenever yet another fragment comes in for that packet.
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