Airport Network maxes out at 100Mbps instead of 1Gbps

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Level 1

5 points

Airport Network maxes out at 100Mbps instead of 1Gbps

I have a roaming network of 3 Airport Extreme 6th Gen routers fed from my cable modem and my ISP shows my max speed as 500Mbps. Each of these Airports are connected via Cat 5E cables that are each 20-40 feet long. I have an additional AE6th Gen router that is extending my network wirelessly.

From Wifi, I can get consistently 250 Mbps downloads on a speedtest. Occasionally I get to the 400's and occasionally below 100.

From Ethernet, I consistently get ~90 Mbps and never have gone over 100 on the 2 PCs that are ethernet only and have Gigabit Ethernet ports.

I also have noticed that if I am not near the main router, my speeds do not go over 100Mbps as well.

I assume the first Airport (Main router) is limiting all the Ethernet ports to 100Mbps.

I have checked all my cables and replaced the lone Cat5 cable (max 100Mbps that unfortunately was between the router and modem), doublechecked the possible port speed on the PCs, and even ran a speedtest when connected directly to the modem.

The speedtest ran only on the modem did indeed come in around 90Mbps but to me that doesn't make sense since the Wifi which is farther down the chain has speeds greater than that.

Did the devices detect the Cat5 cable and throttle down to 100Mbps? If so, how do I reset that (done restarts on all APXs)

What other thing could I change to get a faster speed in my home network?

Thanks

Joey

iPhone XS, iOS 14

Posted on Jul 19, 2021 7:03 PM

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Answer 1

Bob Timmons

Level 10

188,780 points

Jul 19, 2021 8:57 PM in response to JM140

I assume the first Airport (Main router) is limiting all the Ethernet ports to 100Mbps.

Not sure why you would assume this if........

From Wifi, I can get consistently 250 Mbps downloads on a speedtest.

Obviously, the Ethernet signal from the main router is sending speeds of 250 Mbps + to the other AirPorts. In other words, if the other AirPorts were only receiving 100 Mbps signals over Ethernet, then the WiFi speeds would also be limited to 100 Mbps.

So, best to not assume anything until you have done more extensive step by step testing.

First things first. Power off all of the AirPorts

Power off and restart the modem

Connect your computer directly to the modem using an Ethernet cable and run 3-4 speed checks that way using a site like www.speedtest.net

What is the average download speed that you see?

What is the average upload speed that you see?

Whatever it is, this is going to determine the max speeds on your network over both Ethernet and WiFi. As you know, WiFi speeds will never be faster than the Ethernet speeds if things are working correctly.

The next step would be to connect your "main" AirPort to the modem, restart the modem, and run a few speed checks using a wired Ethernet cable connection from your computer to one of the 3 LAN <--> ports on the AirPort.

What is the average download speed that you see?

What is the average upload speed that you see?

Now disconnect the Ethernet cable and run a few WiFi speed checks with your computer in direct line of sight to the AirPort

What is the average download speed that you see for WiFi?

What is the average upload speed that you see for WiFi?

Before we add the next AirPort and test that product, how are you determining exactly what AirPort the computer is connecting to over WiFi? You cannot assume that it will connect to the closest AirPort, it may still be connecting to the previous AirPort or another AirPort, so your "tests" will be of no value unless you know which AirPort the computer is connecting to over WiFi.

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Answer 2

Jul 23, 2021 12:01 PM in response to JM140

I have had network cables go bad.

I would change to CAT6

I had exactly this issue with transfer being done at 100mb/s rather than 1000mb/s

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Answer 3

Bob Timmons

Level 10

188,780 points

Jul 20, 2021 6:19 PM in response to JM140

Just the ends? whole cable?

You can replace just the Ethernet connectors if you are sure that there are no broken wires inside the cable. Use CAT5e or CAT6 cabling or higher. The unofficial "standard" in the U.S. is 568B, although a correctly configured 568BA cable should work as well.

You can test the "new" cable by substituting it for the existing Ethernet cable between your modem and "main" Airport Extreme. The performance of the AirPort Extreme will be identical if the Ethernet cable is configured correctly.

Remember that a mis-wired cable will still "work" connection wise, but it will limit speeds to 100 Mbps.

Did the devices detect the Cat5 cable and throttle down to 100Mbps?

If you really are using CAT5 cables, they are long out of date. I would replace the entire cable in that case. CAT5 can sometimes allow up to 1,000 Mbps speeds over a short distance, but the speed will drop down to 100 Mbps after 50 feet or so in my experience.

Checking Ethernet speeds will not be that difficult with a PC, but checking WiFi speeds will be tricky unless you have a way of detecting which AirPort the PC is actually connected to. You cannot assume that the PC.....or an iPhone / iPad.....is connecting to the closest AirPort. Macs will usually do a nice job of determining the strongest and fastest signal.

If you have a Mac laptop, there a few easy ways to determine exactly which WiFi device is connecting to which AirPort. Post back for tips if you need them.

The bottom line.......get Ethernet up to speed on the AirPorts first......then check WiFi. If the "main" AirPort is working well, then add only the 2nd AirPort and run your checks.....before.....you add any other AirPorts. It's a slow, step by step troubleshooting process when you have multiple AirPorts on a network.

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Answer 4

JM140 Author

Level 1

5 points

Jul 20, 2021 4:50 PM in response to JM140

To make sure I am clear where you replied:

...I assume the first Airport (Main router) is limiting all the Ethernet ports to 100Mbps.

...Not sure why you would assume this if........

...From Wifi, I can get consistently 250 Mbps downloads on a speedtest.

I was trying to say that it is getting to the first Airport at full speed and broadcasting Wifi at full speed but the outgoing LAN ports were limiting for some reason to 100Mbps.

Sorry if I was unclear in my wording. I was having a hard time explaining it in my post.

ADDITIONALLY: I also noticed that the light on the ethernet port blinks reddish when i use the 568A cable and green when I use the 568B cable (the short one that goes from modem to the first Airport). So it looks to be clear I need to replace the cables.

Just the ends? whole cable?

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Answer 5

JM140 Author

Level 1

5 points

Jul 20, 2021 4:32 PM in response to Bob Timmons

BOB! my networking guru! I am so glad you were the one responding, thank you.

I was having a hard time wording things. My assumption was that it was 100Mbps downstream of the first Airport since the Wifi coming off of that one was so high. But from there to the the rest of the network was max 100.

I did as you said and confirmed my assumption with one new discovery.

Direct from Modem using the cable that goes to the PC~92Mbps

Direct from modem using the short cable that I usually use to get to the Airport~450Mbps

Wifi from First Airport ~400Mbps

Ethernet to all other locations ~90Mbps

So I am getting full speed to the first Airport and then reduced from there out on the LAN side.

However, ALL of the cables are Cat5E. I had earlier replaced the lone Cat5 cable which was from the modem to the Airport and checked al the others, so everything is Cat5E. BUT, I noticed the cable from the modem to the first Airport is wired 568B (Orange to Brown) and almost all the others are wired 568A (Green to Brown).

I didn't think it would make a difference since they are the same on each end of the cable but does it??

Could poorly crimped ends cause the speed drop (I used install cable and crimped the ends)? (I always thought ethernet either worked 100% or it didn't at all)

Could it be that since I had the Cat5 cable in the first location, the Airports are assuming it's still Cat 5 and sending a 100Mbps speed instead of at full speed?

What do you think?

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Airport Network maxes out at 100Mbps instead of 1Gbps

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