I am so disappointed with Networking Stability in Mountain Lion

What security protocol are you using? Have you tried changing the channel on the router? Is there 2.4 ghz equipment in the proximity that may be interfering with your reception? Are you using 2.4 or 5.0 ghz for the Macs?

Modem. What brand? What kind of Internet service? Cable? DSL? Is the modem connected as a primary or split?

There is a 4th gen AEBS in the room with me serving 2.4 and 5Ghz to Windows, Mac, iPad, iPhone, and Android clients. No observed instability wireless or wired. The wireless power was actually reduced as a courtesy (what was I thinking) to the neighbors.

In the outside chance that you have an Ethernet chip degrading (or duplicated hostname or IP address) in one of those Macs, you might need to systematically remove each one, and re-evaluate network stability as a result.

Additional questions for insight:

1. Airport Extreme firmware current?

   What generation AEBS?

2. Access to Airport Utility v5.1 (increase wireless power)?
   1. ML invalidated this app, so need Lion or earlier.
   2. Airport Utility v6 unable to change wireless power.
3. Network stability issues only with wireless, or wired too?

   Wired is CAT5E or better?

4. IP Address collisions
   1. Duplicate IP addresses?
   2. Static IP within DHCP IP assignment range?
   3. Duplicate host names?
   4. /etc/hosts modifications?
5. Duration of DHCP renewal window?

Have you considers the possibility that your Airport Express has failed. To suggest that there is something inherently wrong with Mountain Lion is just silly. Wouldn't 5 or 6 million of us have noticed something?

Considered - can't edit on an iPad

Are all of your Mac operating systems at 10.8.2 + supplement, or current for their OS X version?

Power all the routers and networked Macs/peripherals off.

Power on one router, and two Macs only for that network segment. Do your network instability problems remain, or has this combination eliminated the problem? I still think something is perturbing your network, and process of elimination may require time investment, and isolate the problem.

Studio Engineer wrote:

I have 3 Airport Extremes... Unless they all fail at the same time, this is NOT the problem...

Do you have them all set to the same channel or something?

Ehm... goto an apple store and you will find their network to be highly erratic as well...

Mountain Lion is NOT relible when it comes to networking. At all..

Nonsense. I don't go to an Apple Store all that often. My Mountain Lion machines work fine in all other places.

Even the Apple Care folks told me "we are AWARE of problems with networking in Mountain Lion"

Nonsense.

Perhaps YOU are not utilitzing networking on a prefessional level, meaning IT HAS TO WORK ALL THE TIME ;-)

It does work all the time.

Well, I am not having a genius moment on a magic fix. Grrrr.

Within the Network Preferences > Advanced > Proxies setting on each Mac, can you check that the following are not selected within Ethernet and Wi-Fi services:

Auto Proxy Discovery

Automatic Proxy Configuration

It has been reported that unchecking these protocol choices resolves some network instability issues. Here is a screen shot of my panel:

For wireless instability, it has been shown that creating a new Location in Network Preferences, then connecting through that Location, and then renewing DHCP eliminates wireless instability. I would not, however, follow their secondary advice on changing your default MTU value.

Also, do you have any Virtual Private Network (VPN) connections active when you experience network instability issues?

Studio Engineer wrote:

You are not helping at all. You are venting.

You are the one ranting.

Would have thought someone with your amount of posts would at least have had one constructive suggestion,

And you would be wrong, because I have given you two constructive suggestions.

Please refrain from adding posts to this thread. I am not reading them nor am I taking them seriously.

And man, if NO ONE would have those problems WHY on earth does THIS follwing thread have 32,000 VIEWS....

Get your facts straight.... PLEASE

https://discussions.apple.com/thread/4136718?tstart=0

I'll be more than happy to leave you with your dysfunctional network, but not without at least doubling my previous count of constructive suggestions.

This is a user-to-user tech support forum. It is not a place to learn anything about system performance or reliability. If you try that, it will just lead to some mistaken impression that whatever problem you are experiencing is some kind of inherent problem in the operating system. The fact that 32,000 people have looked at a thread does not mean they have that problem. Even if they did, that would leave at least 6968000 Mountain Lion users with no networking issues.

You are reporting problems with everything involving extensive system modifications, multiple routers, and both wired and wireless connections. The only way you are ever going to resolve this issue is to give up on the idea that there is something wrong with Mountain Lion and start a process of elimination to find out what is going wrong.

Take one machine, erase the hard drive, and reinstall the operating system to get to a known, working configuration. Take it to an Apple Store or some other network that is known to be good. Once you know that device is working properly, then you can start with it and attach new devices one by one until it stops working. The problem could be something as simple as a bad cable.

Unfortunately, you are going to have to do all of this on your own. You have asked me to leave and I will do so gladly. I've given you all the tools and instructions you need to fix your network. It is your choice to either fix it or dump it and go to Windows. Either way, I'll be happy.