Intel have released some information about ECC in their networking cards;
Some of the older chips like the 82571 – found in cards like the Pro/1000 PT single/dual/quad port NICs – actually do have error correction on the in-band traffic, which is good news. You can see that the latest generation (i.e. i-350, i-540 etc.) have ECC on both the in-band and out-of-band (management) traffic – that’s on top of benefits like lower TDP and CPU consumption.
Of note is that the more common chips for onboard Intel Gigabit LAN ports – e.g. 82574L – doesn’t feature ECC or parity at all on either in-band or out-of-band traffic. For those who are trying to create the most stable, secure system possible this is a consideration which may prompt you to look at some of the newer network cards which do have those features. I would think that for the majority of users it’s unlikely to have a significant impact on your data long-term but if you’re buying new, it pays to have all the facts. Also, for those of us who are paranoid about data corruption, well, there’s now one more place you can have ECC for your peace of mind…