Q: Lion WiFi Connection Problem

What about Mac 101, CT? There are 159 pages of posts in this thread alone, and almost as many in a number of other threads/forums on pretty well the same issue. As far as I can tell, nobody has come up with a definitive explanation of the cause(s) of the problem, far less a solution that works for everyone. I get the impression that many of the posters have skills/expertise/knowledge way beyond 101 standard.

bratman91 wrote:

 

What about Mac 101, CT? There are 159 pages of posts in this thread alone, and almost as many in a number of other threads/forums on pretty well the same issue. As far as I can tell, nobody has come up with a definitive explanation of the cause(s) of the problem, far less a solution that works for everyone. I get the impression that many of the posters have skills/expertise/knowledge way beyond 101 standard.

There is not "the problem", but rather lots of different reasons why people are having networking problems.  The fact that they come here and find a huge list, is what makes them end up here.  The "google" search results will point you here, but also to an aweful lot of different forums and different experiences.

Same here. Upgraded to ML on Sept. 8th and have yet to have a consistent and permanent wi-fi connection since then. Mind you, I have never had a DNS, IP, Wi-Fi problem for the last 3 years (2 with an HP and 1 with my MBPro). I have been on the phone with Apple Support at least 4-5 times in the last week, all calls lasting about 1-2 hours. Nothing but, lets try this, lets try that. Spoken with techs in Wireless Dept., Tech Support, and 2 Sr. Advisors. Nothing has worked and it seems as if they have reached the end of their 5 inch binder of "troubleshooting". The last thing to try is to take it to a Starbucks, sit and have some coffee, while I test the connectivity with another router other than my "old" 2010 D-Link DIR-615.

Anything and everything to avoid admitting that ML is the problem. I mean, coincidence I think not. I even had to deal with a very offended techy Kenneth, who literally went off on ME, as if ML was the fruit of his loins and I had just insulted it. No joke.

Someone please find a fix cause I am tired of being "connected" to the wall. I wanna sit on my couch and do my homework.

I have a Dlink dir-655, and the way I fixed my problem was by downgrading the firmware to the shipping version. Its not the same router, but could be a similar issue.

Seeing as how anything Apple has tried for me has not worked, I'll try just about anything. I'll post whether or not it worked. Thanks!!

I looked up your DLINK DIR-615 online.  It appears that your router supports the wifi spec 802.11 in all modes b+g+n.  I am willing to bet that the first attempt to use mode n on your router came with your upgrade to ML. 

There are two kinds of mode n: the one version operates at 2.4GHz, and the other at 5GHz.  Some older routers only support mode n at 2.4GHz.   My personal experience is that I had a cheapie older router (ca early 2011) that only supported mode n at 2.4GHz.

My personal fix for the "Mac wifi problem" was to set my router up so that only modes b and g were allowed.  After I made this change, my wifi problem ended.   Note that very little bandwidth is lost between mode g and mode n at 2,4GHz.

Several months later, I bought an airport express, which supports mode n at 5GHZ, this has also been working flawlessly.

My conclusion was that either 2.4GHz mode n support is flaky in my old router, or 2.4GHz mode n support is flaky in the Mac hardware or software.   In any event, I would suggest you try to set your DLINK up so that only modes b and g are allowed.

NOTE that this does not solve everyone's problems.  Some people have already tried this and it hasn't worked for them.   But since I have checked that your router does support some kind of mode n, this may very well be worth a shot.

On my iMac Lion, I tried just about everything I could find in this and other forums and finally changed the MTU to 1450 (Network Preferences > Wifi > Advanced > Hardware > Custom) and this seems to have cured the problem I was having, at least to some extent. My wireless router has a power saving option which I had set to turn off the radio during the night. In the morning, the old problem of "no connection to the internet" was there and I had to turn off and on the wifi to re-establish the connection. I have now turned off the power saving option on the router and wifi connectivity has been continuous for the last 3 days. My iPad and IPhone never lost connection (other than when the power saving option was in play) so I don't think that the router was at all faulty. However, it does seem as though the particular combination of the router and iMac wifi has caused the problem for me.

It may be that there is a Nagel-Algorithm issue with your router, if changing the MTU helped.  There used to be many different ways this showed up, but primarily, the Nagel Algorithm is an attempt to optimize packet flow on the network, by not sending a packet until either a certain time period expires, or "enough" data is available.  It can cause "delays" in data flow, which can cause some protocols, which are chatty, to end up in endless retry loops in some cases.

The http://www.stuartcheshire.org/papers/NagleDelayedAck/ page describes one such example of this behavior.  If you are interested, you might change changing the MTU upward, one byte at a time, until the problem reappears, and then see if there is a "window" of failure by continuing to go up, to see if it goes away again, and then later comes back when you get to the old MTU value.

Would be interesting to know if there is a brand of router which has this specific behavior.

Gpbonei,

Your post sounds time as the best rational explanation I have seen up to now. it gives me some hope for that issue that I have desperately tried to resolved with my 20y of experience in IT.

The MTU value set to 1453 was up to now the best improvement, further to "new location" to force a rest of network settings, disabling of sleep mode, and move to fixed IP instead of DHCP, disabling of WIFI icon, regular running of WIFI diagnostic, policy of regular reboots, ..., But the problem had sill not gone. I will seriously look into your article.

My router is a Belkin N+, F5D8235-4 with firmware 1.x generation

Dear Gphonei,

I am glad that finally someone payed attention to what I said about changing ISP and the problem in Nagel-Alg.

But it whould be a better netiquette to cite the original idea ( as I mentioned my friend the first time I put it here:)

https://discussions.apple.com/message/19404644#19404644

(I have no objection, and don't get frustrated friend; It was just a friendly comment !! )

I just want this problem to be solved because I adore Apple .  Just go on  . I think the solution -what ever is , or at least partly- is in this article.

I should remind to those who have not seen my previous posts, after changing ISP I have not had even one drop-down in connection for nearly 10 Months.

Been dealing with this issue for a year now... I've been running a cisco network at home for years without any problems.  WIndows, G4, Ipads, iphones, droids.. apple TV, media servers.. bla bla bla...   all working without any problems.  Last year I picked up an iMAC with lion... first week.. started having wi-fi problems, got so bad, I had to wire it in.

Original Configuration

ISP: Time Warner

Modem: Arris

Router: Cisco E4200

Wireless: Cisco Aironet 1130g

Forward a year later.. upgraded mac to Mointain Lion... problem still there.. Frustrated, went out and replaced everything with Apple networking hardware...

Today's configuration

ISP: VZ FIOS

Modem: Motorolla

Router: Time Capsule 2TB with Airport extreme base station

Repetars: 2 Airport express

Guess what, problem still there. 

Deleted the system preferences..  no help..

Back to CAT 6..

Lesson learned...  its an Apple problem and they should step up to the plate and fix it!  

TSKman3 wrote:

 

Been dealing with this issue for a year now... I've been running a cisco network at home for years without any problems.  WIndows, G4, Ipads, iphones, droids.. apple TV, media servers.. bla bla bla...   all working without any problems.  Last year I picked up an iMAC with lion... first week.. started having wi-fi problems, got so bad, I had to wire it in.

 

Original Configuration

ISP: Time Warner

Modem: Arris

Router: Cisco E4200

Wireless: Cisco Aironet 1130g

 

Forward a year later.. upgraded mac to Mointain Lion... problem still there.. Frustrated, went out and replaced everything with Apple networking hardware...

 

Today's configuration

ISP: VZ FIOS

Modem: Motorolla

Router: Time Capsule 2TB with Airport extreme base station

Repetars: 2 Airport express

 

Guess what, problem still there. 

 

Deleted the system preferences..  no help..

 

Back to CAT 6..

 

Lesson learned...  its an Apple problem and they should step up to the plate and fix it!  

I keep hoping that someone who can reproduce the problem this reliably can spend some time to track down what the real problem is.  Some people see their "airport" signal go to "zero", others have full bars, but their browser says "you are not connected to the internet".   Can you tell us more about the failure mode you see?  If you open a terminal window, when you are not connected, can you "ping" your airport extreme?  Can you ping the google central server at 8.8.8.8?  It would be great to learn more about the failture mode you see, thanks for anything you can report.

Airport signal nonexistent, asked to join network again... Browser says you are not connected to the internet and cannot access network drives.  Time Machine and Skydrive access backup and sync halted.  Haven't tried the ping or google central will do next time.. but from the behavior i would imagine ping failures.

Ok.. as a suspected..  no reply on pings from airport extreme nor google server.  After joining network again..  pings are sucessfull.