Windows 10 mDNS and Broken Wireless Network

[ryan_klingaman_]

Figured I would update here since my support case at Ruckus has gone quiet nobody wants to talk back at me there and the other contacts at Ruckus have been quite as well. (end stab at Ruckus communication)

The real reason for this post was just to help someone out on an issue that we discovered. Our original problem started at with IOS devices and horrible speed. Then after some ping tests we saw horrible latency and lots of dropped packets. Other wireless devices like Windows 7 Laptops were just fine.

Then start looking at my wired switches and all of them had higher CPU utilization from last semester (we are at a college). More digging didn't point to any particular bad device spewing traffic just elevated traffic all over. While watching the traffic flows on the switches noticed a lot more mDNS Bonjour traffic then normal and the offending IPs were actually windows 10 devices.

The only information I found online was this recent forum post:

https://social.technet.microsoft.com/Forums/en-US/b334e797-ef80-4525-b74a-b4830420a14e/windows-10-sp...

After that I checked the box on my wireless controller to block Multicast traffic. Instantly after checking that box my CPU utilization went down on the switches and I had a happy wireless network.

[michael_brado]

Hello Ryan,

    Your observations and report to us is very valuable, especially as new OS flavors

appear.  Your (college) environment will likely have lots of mDNS from Apple devices

too.  As Win10 is a free download to many MS users, we do need to be aware of these

type of early implementation issues.  Managing multicast thru the wired and wireless

network is important to the type of services you're providing.  Where possible try to

limit broadcast domains and segment VLAN traffic to reduce too many small packets

that need to be inspected nonetheless.  I'll create a knowledge article with your info.

Thanks and best regards.

[monnat_systems]

Ryan,

excellent find and thanks for sharing with the community...