Can anyone explain to me WTF is going on with my network?

[The.316]

So I recently upgraded to 100/10. I get the new modem/router from the phone company, and I seem to be doing fine; 95 ethernet, 90 wifi, on my iPhone X BTW. I change the router's wifi name and password, and continue to set up the rest of my house (iMac, MB, security camera, etc.). As soon as I enter the wifi password on my iMac, the speeds drop to 45-50. I do a speed test on my iPhone, and its the same, 45-50mbs. I noticed that in the settings of the router, it had both 2.4 and 5ghz enabled, with both of them having the same SSID, so I switched one to show that it was the 5ghz mode. Now, when I have both my iMac and iPhone on the 5ghz speed, they are back at the 92-95mbs speeds. I do not understand what the issue is. I havent connected everything else yet because Id like ti figure out what is going on. My questions are:

1. Why is the average speed on the 2.4ghz half of what it is on the 5ghz?

2. Do the two current devices talk to each other?

The reason to the second question is this. When I disconnect my iMac or iPhone from the network, meaning "forget network," it immediately disconnects the other device from the network as well. (iMac is running High Sierra and the iPhone X is running beta 12 BTW.) Ive either never seen that before happen here, or I just might have never noticed it.

This isnt really something recent either. I upgraded a few months ago, and have been at a constant 45-50mbs download speed. I called the phone company last night, and they replaced my router, thinking it was the old routers fault. I noticed after configuring the new router, that it had both 2.4ghz and 5ghz enabled, and i remember the old router would only allow me to have one or the other active. So im thinking that since both ghz were named the same, maybe the devices couldnt differentiate between the two? Is that an option?

 

[DJLC]

1) How old is the iMac? It's possible that the iMac isn't supporting the same data rates as the iPhone X. If this is the case, it would explain why you see degraded performance when the iMac is connected. The older device forces the wireless network to slow down so it can connect. Splitting into a 2.4GHz and a 5GHz with different names will allow you to put the old device on one and the newer device on the other; however, the network that the older device is connected to will still see that degradation.

2) Are you using iCloud Keychain? If so, the known networks on your devices are being synced. If this isn't desirable, you'll have to disable that on one of the two devices.

 

[The.316]

1) How old is the iMac? It's possible that the iMac isn't supporting the same data rates as the iPhone X. If this is the case, it would explain why you see degraded performance when the iMac is connected. The older device forces the wireless network to slow down so it can connect. Splitting into a 2.4GHz and a 5GHz with different names will allow you to put the old device on one and the newer device on the other; however, the network that the older device is connected to will still see that degradation.

2) Are you using iCloud Keychain? If so, the known networks on your devices are being synced. If this isn't desirable, you'll have to disable that on one of the two devices.

1. The iMac is a 27" late 09 model.

2. Its running on both home PCs; the iMac and MB.

Ever since I changed the names to differentiate between the two networks, and placed everything on the 5ghz, everything seems to be running fine. The only thing I am going to run off the 2.4 network will be my wireless printer and security camera. I dont even want to think about going back to the 2.4 network to try and see if there is still a problem, since it seems to be working fine now. I still dont understand when I first connected the iMac to the network though, it ran fine, but the speeds dropped to half as soon as I connected my iPhone to the network as well.

 

[techwarrior]

2.4Ghz suffers from interference. Microwaves, Radars, Bluetooth, wireless home phones, wireless keyboard\mice, all transmit on 2.4Ghz frequencies, all tend to use right around channel 6 frequencies. Even USB3 drives connected to routers can emit 2.4Ghz noise.

Routers default to channel 6, why? To be annoying I suppose. In most routers, you can manually set the channels on both 2.4 and 5Ghz. Also, If you see neighbors WiFi when you go to connect, chances are that are 2.4Ghz and channel 6 and causing collisions.

WiFi is kind of a helter-skelter access technology, every radio wave in the frequency range has to be read and either forwarded or discarded by both your router and devices. Ethernet requires physical connectivity and is full duplex so it is easier to discover when it is clear to send data and less likely to have interference or collisions. With WiFi, you often end up sending\retransmitting a bunch of times if the router is getting hit with a lot of noise or traffic, that is what appears as a slower connection. Since 5Ghz has a shorter range, neighboring networks are usually out of range and most appliances don't interfere with 5Ghz.

2.4 is also slower than 5Ghz in general. So, best to keep SSID named separate and connect to 5Ghz if you can, then fall back to 2.4 if needed for range.

 

[The.316]

2.4Ghz suffers from interference. Microwaves, Radars, Bluetooth, wireless home phones, wireless keyboard\mice, all transmit on 2.4Ghz frequencies, all tend to use right around channel 6 frequencies. Even USB3 drives connected to routers can emit 2.4Ghz noise.

Routers default to channel 6, why? To be annoying I suppose. In most routers, you can manually set the channels on both 2.4 and 5Ghz. Also, If you see neighbors WiFi when you go to connect, chances are that are 2.4Ghz and channel 6 and causing collisions.

WiFi is kind of a helter-skelter access technology, every radio wave in the frequency range has to be read and either forwarded or discarded by both your router and devices. Ethernet requires physical connectivity and is full duplex so it is easier to discover when it is clear to send data and less likely to have interference or collisions. With WiFi, you often end up sending\retransmitting a bunch of times if the router is getting hit with a lot of noise or traffic, that is what appears as a slower connection. Since 5Ghz has a shorter range, neighboring networks are usually out of range and most appliances don't interfere with 5Ghz.

2.4 is also slower than 5Ghz in general. So, best to keep SSID named separate and connect to 5Ghz if you can, then fall back to 2.4 if needed for range.

I did the network analysis that Mac offers, and it recommended that the best channel for 2.4 was channel 6. The other three routers around me were all either channel 1, 10, or 11. It’s also recommended me certain channels for the 5Ghz. Should I switch it to those channels, or just leave it at auto?

 

[techwarrior]

I did the network analysis that Mac offers, and it recommended that the best channel for 2.4 was channel 6. The other three routers around me were all either channel 1, 10, or 11. It’s also recommended me certain channels for the 5Ghz. Should I switch it to those channels, or just leave it at auto?

I would only change 5GHz channels if there is a need, if your performance on that frequency is ok, leave it alone.

 

[The.316]

I would only change 5GHz channels if there is a need, if your performance on that frequency is ok, leave it alone.

OK, appreciate the help!

 

[Howard2k]

It’s not just the frequency. In the 2.4Ghz space, the iMac also supports only 802.11g. Or perhaps draft 802.11n depending which specific one it is. In the 5GHz space, 802.11a but not 802.11ac. But it could be iMac is forcing your 2.4Ghz network to drop to 802.11g compatible timing.

If all your traffic is going to the internet anyway, then you need to right size it for that and not worry about it too much. If you’re planning to move traffic locally between devices, you need to invest some time to work out the right deployment of devices across your spectrum.

Wifi is messy, as noted, but a lot of issues are easy enough to work around.

Without knowing anything about signal strengths and other wifi networks, my kneejerk reaction would be to use the 5GHz space for the iMac, if it has the signal strength, and the 2.4Ghz space for the iPhone. The reason I would do it this way is because the 2.4Ghz network has a longer reach than the 5GHz, and if you’re moving around your home this may be advantageous for the iPhone.