Why does my Airport Wi-Fi Network hierarchy change sometimes ?

All the other Airport Extreme's and Airport Express's are all setup to "extend the network".... I just wanna be able to provide the very best wi-fi I can throughout my home for my family and devices.

For best Wi-Fi performance, it's important to understand how the AirPort base stations extend a wireless network. A good analogy is to use a wheel. The base station that is to be extended (your 802.11ac Extreme in this case) would be at the hub of this wheel and each of the extending base stations would be along one of the spokes. The farther along the spoke away from the hub the poorer performance of the extended network.

Ideally, for the best overall bandwidth you would want all of your "extending" base station connected back to the main by Ethernet ... or, as you have suggested, by using Powerline adapters. This type of configuration would be known as a roaming type network. With this type of network, each base station would broadcast its own Wi-Fi network, but since all will use the same network name and wireless security type and password, wireless network clients would see it as "one" network. This would allow them to roam between base stations and still be connected to the same network.

The biggest issue with wireless-only extended is dramatic loss of bandwidth. As you can imagine, this can affect streaming, especially HD video, performance and appear as skips or dropouts.

The core problem I had is that I presumed that by adding more Apple Express Extenders to my system I would improve my wi-fi throughout my home without trying first to even see if the one unit alone would do the job.

Your presumption was very reasonable considering you were, most likely, relying on manufacturer advertising on what you can expect with their products. The "devil is in the details" when it comes to this information.

Unfortunately, this doesn't always play out in the real world ... as you can attest first-hand. The key to success with Wi-Fi, especially, when you need to cover a large area AND want the best possible bandwidth performance, is to first establish a solid network backbone based on Ethernet (or powerline adapters). You can then "fill the wireless coverage void) by strategically placing wireless access points where needed that is connected back to this backbone.

Currently, from best-to-worst overall Wi-Fi bandwidth performance:

1. Ethernet backbone with Wireless Access Points (WAPs) - These are typically deployed at business or educational locations. However, there are a number of manufactures that provide these for home use as well. For example, Cisco or Ubiquiti
2. Powerline backbone with WAPs - Not commonly used in commercial environments, but more so, for homes without Ethernet pre-installed in the walls.
3. Wireless Mesh networks - The current trend. These networks do not require wired connections between WAPs.
4. Wireless routers with wireless extenders - What you have now. Our suggestions, to improve this, is to configure your network for either the first or second item above.

But sometimes when either I add a new Airport Express or I restart the network the layout and configuration can change when I view my network using the Airport Utility.

My main source router remains always under the Internet icon... but sometimes the other can be all in a straight line or as now some or under others... the hierarchy changes from time to time.

Is this a good or bad thing.

Welcome to AirPort Utility version 6.x! 😉

What you are experiencing, as far as random changes of the network graphic, is "normal." This seems to be the standard since version 6 of the AirPort Utility has been released a few years ago. Nothing to worry about. Hopefully, Apple will release a "stable" version in the future.

Sometimes some have Excellent signal, other times Good...

Is there a way to fix the layout of the access points to get the very best results...?

If your current network configuration with all of your AirPort base stations is per the graphic, then would I be correct to assume that each of your base stations are wirelessly connected back to your "main" AirPort Extreme? If so, are all of these base stations configured to "extend" the Extreme's Wi-Fi network? Or are some of the Express base stations configured to "join" it for AirPlay? ... or some combination of both?

I just wanna be able to provide the very best wi-fi I can throughout my home for my family and devices.

Unfortunately, in your current configuration above, two of the AirPorts.....Heather's Bedroom and Arcam are not "extending" the network at all......because Apple will not allow a network to be extended twice using two "hops". In other words, you cannot "extend" an AirPort that is already set up to "extend a wireless network".

It's important to understand how Apple's "extend a wireless network" setup actually works.....which is based almost exclusively on wireless signal strength.

So, if you want the four AirPorts under your "main" AirPort to all extend the network....each one of them needs to pick up about the signal strength from your "main" router. That would mean that.....

1) All four extending AirPorts need to be located about the same distance from the main AirPort

2) Each one of the four extending AirPorts needs to be located closer to the "main" AirPort" than any other AirPort

To arrive at the correct setup, think of Apple's "extend" feature like the hub and spokes of a wheel. Your "main" AirPort is the hub and each other AirPort resides at the end of a separate spoke. As such, each of the extending Airports communicates directly to the "main" AirPort......not to another AirPort at the end of another spoke.

When all four AirPorts are extending the network, they will all be lined up horizontally side by side in the AirPort Utility graphic.

I now have two in the same room... my living room.... the ARCAM/ROTEL named Express is for my hi-fi system... so should I just get rid of the Samsung dedicated Express... move it somewhere else... I thought by having it next to my TV, connected via ethernet I would get the max out of it..?

If you mean that the AirPort near the TV is connecting to the "main" AirPort using wireless, and you have an Ethernet cable installed from the AirPort to the TV........then the "Ethernet" connection is only going to be as good as the quality of the wireless link between the AirPort near the TV and and the "main" AirPort.

If this is the case, you are in effect really connecting the TV using wireless. So, it would likely help to eliminate the AirPort near the TV and simply have the TV connect using wireless to the other AirPort in the same room.

Keep in mind that when you "extend" using a wireless connection between AirPorts, that you want to use the absolute minimum number of AirPorts to do the job. Reason.....you will lose about half of the potential speed on the network link when you "extend" using a wireless connection. Multiply that times the 3 or 4 extensions that you have, and the network will really slow down signficantly. True, you may have better signal "strength" by using more AirPorts, but you will have a slower network when you do this.

The bottom line unfortunately is this......when you "extend" using wireless, there are going to be compromises in performance. The best way to connect the AirPorts together would be a wired Ethernet cable connection between them. Since there is zero signal loss though the Ethernet cabling, each AirPort works at top speed. If you cannot run the Ethernet cable, then powerline adapters will almost always provide a better alternative than using only wireless.

Your "updated" screenshot with the 4 AirPorts all lined up horizontally indicates that the network is working correctly. It will operate a bit better if you can eliminate one of the AirPorts, since there is significant loss with each one that you use.

Well, if you are happy with the performance of your network at this time, you might just want to leave well enough alone. Or, see if you can get by with one less AirPort for now, if you want to gain back 20-25% of the network potential speed.

Even though the speed potential of your network has diminished with each "extending" AirPort, the network may still likely be faster than your Internet connection provides to you. So, unless you have a really fast Internet plan with your provider.....something in the 150-200+ Mbps range, you won't really see any significant improvement by going to Ethernet connections or powerline adapters.

On the other hand, if you are copying files back and forth from one device to another on your network, then that process will speed up with a more efficient network design.

The deal with powerline adapters is that they work best when they are on the same electrical circuit. That's rarely the case when you are installing AirPorts in different locations around the house that will no doubt be on other AC circuits.

How well.....or, even if.....powerline adapters will work when they have to jump or hop circuits cannot be predicted in advance, despite the nice looking advertisements that you might see.

You have to try out the adapters in your home to find out if they will work correctly and provide a faster network. So, if you decide to try the adapters, it would be a really good idea to understand the store's return policy in advance before you buy.

Small amount of ethernet can make a world of difference..

In terms of cost, try out the powerline adapters.. one pair.. but the trick is to use them in the most strategic area.

For example the weakest link in most wireless setups is upstairs downstairs connections.

And of course as Bob noted.. the very place where you need powerline to work will almost inevitably be the spot it does not work.

Getting an ethernet link installed from the most useful place upstairs to the most useful place downstairs.. good cablers can do excellent job with total wife acceptability (ignorance??). SWMBO (as Rumpole used to say) does not always need to be informed of all the necessary activities. (From a technical standpoint).