Q: OSX Yosemite Wifi issues

Thence my suggestion to keep iOS devices out of range of your MBA: to see if the switching reoccurs, to ascertain iOS is doing the switching. Might be some Discoveryd component of Yosemite itself...

Not sure what you mean by out of reach, other than having them not use my wifi, which unfortunately is not an option right now since I'm also investigating unrelated iOS issue. Let me be more specific about what I mean though

While doing some iperf tests on my MBA, I noticed that I was getting speeds consistent with being on the 2.4Ghz. Sure enough, the MBA had somehow moved to the 2.4ghz SSID and magically reappeared in my list of preferred networks. My iPhone 5s was also connected to it. As soon as I removed the preferred network from my MBA, the iPhone got kicked out and moved back to the 5Ghz SSID on its own.

What about my ipV.6 question? Thanx!

For this particular issue, I don't think ip v6 come into play. In any case I have a slightly different network setup than most people I suspect although through my testing I have found it makes no difference. When I started getting all these wifi issues with iOS 8, I got the Airport Extreme, figuring that if Apple was going to test one AP, it would be that one. While it did not fix any of my issues, it did have a bit of a better signal than my older router, so I decided to keep it.

I now have a dedicated router and the Airport Extreme AC is set up as a bridge, so it gets its ipv4 address via the router's dhcp server. As mentioned, this set up has not made my issues better or worse. It's just more convenient for me.

My attempted edit of previous post to update after restart failed....

Wifi connected automatically - 5GHZ - and no sign of mDNS files in Activity monitor

Will mail you, Paul, for sure.

Although I'm not an IT specialist, just a humble OSX workaround fanatic, this line looks very suspicious indeed:

Does this actually mean Discoveryd is using some mDNSResponder code, or that mDNSResponder and Discoveryd have been running concurrently while your internet connection crashed? And -worst suspicions come true- without leaving too many traces of mDNSResponder or mDNSResponder_helper having been active while YO1010 was supposed to run only Discoveryd?

Though I'm not very good at reading Console logs, we may have a lot to talk about...

My attempted edit of previous post to update after restart failed....

Right Paul, there seems to be a bug here with logout timers: if you leave a reply window open long enough and even if you're not yet logged out, you still lose the "reply" option. Seen it a few times these 2 weeks.

Logout then login do not remedy either.

Sorry for the off topic, folks!

I'm not sure what all this discussion about mdnsresponder is, but I think I can answer some of the questions

As of Yosemite, mdnsresponder (Bonjour) functionality has been integrated into Discoveryd. What you are seeing in that output is simply the discovery daemon running as the _mdnsresponder user, which is just an internal user Mac OS X uses. You can confirm this with the following command:

cat /etc/passwd | grep _mdnsresponder

Not sure what you mean by out of reach, other than having them not use my wifi

Exactly that was the test case: not having iOS Devices use your Wifi in order to ascertain they were the culprit in changing your channels to the 2.4 GHz range.

While doing some iperf tests on my MBA, I noticed that I was getting speeds consistent with being on the 2.4Ghz. Sure enough, the MBA had somehow moved to the 2.4ghz SSID and magically reappeared in my list of preferred networks. My iPhone 5s was also connected to it. As soon as I removed the preferred network from my MBA, the iPhone got kicked out and moved back to the 5Ghz SSID on its own.

That is consistent with the workarounds having you clear the SSID list, or creating a new network name. As already surmised, this may be only temporary, like some cache rebuilding. Seems like Bonjour playing bad.

For this particular issue, I don't think ip v6 come into play.

In that case, have you considered killing your ipV.6 altogether or rerouting it to link local only (as suggested before here) and see what happens?

Thanx, Wombat2k, have to quit now. CU!

Ah, great thanx Wombat2K! Will check this tomorrow, really have to sign off now. So sorry!

Tom & uva14 --

Bluetooth seems to be the core of the problem.  I'm running a 13" MacBook Pro Retina 2014 with Yosemite installed.  I have a 3T Airport Time Capsule and it sits on the desk near the laptop.  As a diagnostic tool I'm running WiFi Explorer (in the Mac Store and highly recommended).  I will attached two images from this tool.  The first shows typical 2.4 GHz (BROWN) and 5 GHz (BLUE) signal strength in my "normal" configuration (laptop cover closed, Bluetooth ON, and a Thunderbolt display, keyboard, and track pad in use). Notice that the 2.4 GHz line (BROWN) drops repeatedly for up to 1 minute.

The second image shows what happens when I raise the laptop cover (to use the keyboard and trackpad) and then turn off Bluetooth.  In this image I turned off Bluetooth at exactly 19:15 and 30 seconds.  You can see that the 2.4 GHz channel is solid and stabilized as soon as the Bluetooth was disabled.  I let the display run and the second image shows good stabilization.

To MiguelID -- I tried the KeyChain Access modification you recommended but it didn't change this behavior.

The problem is clearly a Bluetooth problem but one that would be less of an issue if the laptop and the Airport Time Capsule were not in the same room.  I plan to experiment by putting a piece of steel on the side of the Airport Time Capsule that is closest to the Laptop to see if some isolation can be established.

P.S.  I'm running OS X Yosemite 10.10.1.

Although I don't have an airport and do have a Linksys, I am located in the same room between a router and a wifi extender because of the issues I've been having.  I have tonight found the same problem on a Macbook Pro (2013).  I can run on 5Ghz but cannot even see my 2.4Ghz network (slightly different name) when my bluetooth is on.  If I go to 2.4Ghz, my bluetooth is knocked off and I'm back at the laptop keyboard.   It seems that the bluetooth is in the middle of the issue, but I cannot see both networks at the same time with bluetooth on.

UPDATE -- When taking my 13" MBP Retina around the house I find that the 2.4 GHz Wifi issue occurs whenever the laptop's Bluetooth transceiver is on, and in any room.  Whether this problem affects the transmission of the Airport Time Capsule router or not is not clear at this time. 

Running the WiFi Explorer app on a 2012 MB Air with the 10.10.1 version of Yosemite OS X produces a different result than with the 2014 MBP Retina.  There is no interference between the Bluetooth transceiver and the WiFi transceiver.

Good point - just remember that if you delete and recreate your wifi settings, IPV6 is re-enabled.  That caught me out the other day when I removed my wifi setting sand  set up   wifi 2 - had to restart my iMac and reboot my modem to get a connection.  Did this twice then checked to see that IPV6 was enabled again.  Problem solved by setting to local link only.

S2sns, Caicklen, all:

I run my MBP mid-2010 with lid open usually & 2nd screen, Bluetooth on, 1.5 metres from route. Bluetooth mouse and keyboard in use permanently.  My wi-fi has been a lot better since I started "gardening" at Cupertino's request but before 10.10.2 I don't remember if Bluetooth was an issue.   Airdrop is switched off.

Don't know if this helps or not.

Paul

Still absolutely no answer or suggestions from Apple staff at all? This has been going on for months!

My wifi issue seems to center around the stack that Safari is using.  Chrome will continue to work after Safari refuses to load pages.  Sometimes I have to refresh multiple times with Safari before a page will display properly.  I've noticed a few other applications (App Store) that refuse to connect once the wifi starts misbehaving, but I can always go to Chrome and it will function (and no it's not working off a cache).  I tried 10.10.2 and it seemed (probably my hopefulness) better, but still has the same issue.