Two suspect NICs at this point:  
- Intel® 82579LM found in some HP laptops.   Disabling the IPV6 TCP checksum 
offloading resolves the problem.  
- Realtek RTL8111E - The problem is inconsistent  


-----Original Message-----
From: Ryan Rawdon [mailto:[email protected]] 
Sent: November 18, 2015 09:22 PM
To: Clinton Work
Cc: [email protected]
Subject: Re: Windows NIC/driver issues with IPV6 TCP checksum offloading

> 
> On Nov 18, 2015, at 4:17 PM, Clinton Work <[email protected]> wrote:
> 
> Since rolling out dual-stack IPV6 to our consumer Internet customers, we’ve 
> had a couple of customer incidents with very slow IPV6 TCP performance to 
> dual-stacked websites (facebook, Wikipedia.org, …).   The problems only 
> occurs with Windows 7/8/10 PCs connected via Ethernet NICs.   Disabling IPV6 
> TCP checksum offloading will resolve the performance issues in some cases, 
> but not in all cases.   We have tried updating the Windows NIC driver to the 
> latest version, but that didn’t help.   I’m wondering if anybody else has 
> seen this issue with Windows PCs.   
>  

Have you noticed any patterns in what chipset (Intel/Broadcom/NVidia/etc) may 
be involved?

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