Windows 10 creators update slow WiFi connection

[Michiel Joosten]

Hi All,

We we're recently made aware of the following issue with the Creators update of Windows 10 and Intel AC NICs:

https://answers.microsoft.com/en-us/windows/forum/windows_10-networking/wifi-issues-with-creators-update/4a20ba4f-33dc-4397-9823-e12dcb2607ba

Since installation of this update Wireless connections are extremely slow. On the microsoft site someone found three workarounds:

1. Disable Receive Segment Coalescing on the wireless NIC

2. Lower the MTU on client side (1400 bytes seems to work)

3. Revert back to Intel driver version 17.15.0.5 and disable driver update.

We replicated this on controller version 8.2.151.0 and 8.3.121.0 with a 2800 series AP. On other APs (x600/x700 series) we we're unable to replicate.

We also found an extra workaround for the Cisco WLC:

4. Enable TCP Adjust MSS on AP to 1362 or any value smaller.

Advantage is that no changes are required at client side.

Does anybody else have experience or other workarounds for this issue?  Did anybody see this issue with non COS Access Points?

Thanks in advance!

Best regards,

Michiel

[patoberli]

I might have this issue with a single client, based on an Intel 3165 adapter. It's a BYOD device and I didn't have enough time to troubleshoot enough, but at least the Intel 19.40 and 19.60 driver packet didn't solve the issue. It only happened on Cisco 2800 APs, it didn't happen on Cisco 3700 ones.

As it's so far a single client that has an issue, which is only sporadically onsite, I did not yet follow up on this. Maybe it's this issue which you mention here, maybe it's a Cisco firmware one or, most probably, an Intel drive issue.

The slowness was only in the AP -> Client direction, upload from the client was fine.

WLC is running 8.2.151.0.

[Prateek Saxena · Accepted solution]

You can follow the bug here:

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCve26935/?referring_site=bugquickviewredir

[Michiel Joosten]

Microsoft published a fix for this issue recently:

June 27, 2017—KB4022716 (OS Build 15063.447)

• Addressed issue where, after updating to the Creators Update, devices that have Receive Segment Coalescing (RSC) enabled have significantly low wireless throughput. 

I haven't been able to test this fix yet.