[SOLVED] Download Speeds on LAN slower than WAN

RTrobby

Honorable
Oct 12, 2015
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0
10,510
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Hi there,

I usually can figure this kind of stuff out but I'm currently at a loss.

I have Xfinity Internet and a TP-Link Router. My download speeds I pay for from Comcast is 900 Mbps, upload is 25 Mbps. I have the Xfinity XB6 gateway in bridge mode, connected to my TP-Link AX3000 router. When I log into 192.168.1.1 and do the built in speed test on the TP-Link router page, I see speeds about what I should be getting (800+ down, 20+ up). But when I try speedtests on my computers, the download speeds are nothing close. My desktop that is connected directly with a CAT6 ethernet cable to the router is only getting 300 down (tested on Speedtest.net). My other computers and Xbox that are connected through ethernet on a second router with CAT6 cables are also getting in this 200-300 down range. I cannot for the life of me understand what is wrong. Everything I find online states that the ports on the router should not have any trouble giving the full speed downloads, yet I'm at a fraction of what they pull from the modem.

Yes, I have taken the common troubleshooting steps of not having any other internet usage while testing, not using Wi-Fi, etc.

Is this a router problem? Or what else?

Thanks in advance.
 
The main reason for the question on the cables is a lot of people buy those flat cables. The wire is too thin in those cables to meet the standard for the cable to be certified a ethernet cable. They tend to be very unstable especially at longer distances.

I would try hooking your PC directly to the modem you would expect it to get the same speeds as the router.

250-300mbps is a common number to see when the router CPU is processing the data even on a extremely powerful router. Almost all routers even extremely cheap ones use a hardware NAT acceleration feature to allow traffic to bypass the CPU chip. This is how they get gigabit speeds wan/lan.

There are many setting that disable this. Pretty much anything that requires the cpu to look at the data, since it can't do anything if it is being bypassed. The most common are something like parental controls of any other type of traffic filter. Some routers though just enabling a feature that lets you monitor the traffic will disable this.

It should be on by default. The simplest way to test is to factory reset the router and then set only the admin and wifi passwords. Changing the lan IP will be ok also if you need to do that.

If this continues to be a issue what I would test next is to put the comcast box back into router mode and run your tplink as a bridge/AP. It all depends on why you need the router function in the tplink . Most people just want better wifi than the ISP router has. Many of the other features on a router you can't actually use when you have a fast connection.
 

Ralston18

Titan
Moderator
Update your post to include full system/hardware specs.

Provide some sort of line diagram or sketch (post here via imgur.com) showing how your network devices are connected and configured.

Two routers - why?

Reason for Bridge mode use? How and why was that configured?

Source of those Cat6 cables? Specs?

Provide more information about your network, the devices that are installed, and the connections between those devices.
 

RTrobby

Honorable
Oct 12, 2015
18
0
10,510
0
Second router acts as a switch connected to TP-Link AX3000 with 50' CAT6a cable, with no wireless enabled. There are various devices connected wirelessly at any given time, but in traffic monitor on AX3000 there is no traffic on the network when I am testing. The Unraid server also had no activity.

Bridge mode use is the way to disable the router portion of an Xfinity Modem, as I use the AX3000 as my router. The modem/gateway exists only as a box for Xfinity to deliver internet into the home.

The Cat6 cables are varying from random places, and I left a note of the places I knew where they were from on the sketch (this could be the culprit? though it happens with various ones, not any in particular).

View: https://imgur.com/a/0YvYUw0
 
The main reason for the question on the cables is a lot of people buy those flat cables. The wire is too thin in those cables to meet the standard for the cable to be certified a ethernet cable. They tend to be very unstable especially at longer distances.

I would try hooking your PC directly to the modem you would expect it to get the same speeds as the router.

250-300mbps is a common number to see when the router CPU is processing the data even on a extremely powerful router. Almost all routers even extremely cheap ones use a hardware NAT acceleration feature to allow traffic to bypass the CPU chip. This is how they get gigabit speeds wan/lan.

There are many setting that disable this. Pretty much anything that requires the cpu to look at the data, since it can't do anything if it is being bypassed. The most common are something like parental controls of any other type of traffic filter. Some routers though just enabling a feature that lets you monitor the traffic will disable this.

It should be on by default. The simplest way to test is to factory reset the router and then set only the admin and wifi passwords. Changing the lan IP will be ok also if you need to do that.

If this continues to be a issue what I would test next is to put the comcast box back into router mode and run your tplink as a bridge/AP. It all depends on why you need the router function in the tplink . Most people just want better wifi than the ISP router has. Many of the other features on a router you can't actually use when you have a fast connection.
 

RTrobby

Honorable
Oct 12, 2015
18
0
10,510
0
The main reason for the question on the cables is a lot of people buy those flat cables. The wire is too thin in those cables to meet the standard for the cable to be certified a ethernet cable. They tend to be very unstable especially at longer distances.

I would try hooking your PC directly to the modem you would expect it to get the same speeds as the router.

250-300mbps is a common number to see when the router CPU is processing the data even on a extremely powerful router. Almost all routers even extremely cheap ones use a hardware NAT acceleration feature to allow traffic to bypass the CPU chip. This is how they get gigabit speeds wan/lan.

There are many setting that disable this. Pretty much anything that requires the cpu to look at the data, since it can't do anything if it is being bypassed. The most common are something like parental controls of any other type of traffic filter. Some routers though just enabling a feature that lets you monitor the traffic will disable this.

It should be on by default. The simplest way to test is to factory reset the router and then set only the admin and wifi passwords. Changing the lan IP will be ok also if you need to do that.

If this continues to be a issue what I would test next is to put the comcast box back into router mode and run your tplink as a bridge/AP. It all depends on why you need the router function in the tplink . Most people just want better wifi than the ISP router has. Many of the other features on a router you can't actually use when you have a fast connection.
Thank you, factory resetting resolved my issue. I had no idea that the traffic was getting routed through the CPU and that could be a limitation. I tried disabling traffic monitor, but that did nothing. A factory reset did the trick.
 
May 4, 2021
14
1
15
1
The very helpful answer is, But what when the wire is connected with some w10 pc in a few meters distance If their speed range is 250-300 Mbps, is it the same speed for each or different?
 

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