Question Networking Bottleneck and Ways to Fix it

Thought Provoker

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I'll just lay out all the facts and then what I'm looking into, let me know what y'all think.

I pay for 400 mbps internet. I was getting that a few months ago, no problem. I did a random check again today when I hit a download cap of about 12 MBps which was different from the regular ~30 MBps I could get on any regular download. I had a technician come out here and checked all the wiring, no problems and even tested the internet and we got ~450 mbps when hooked directly to the modem. I checked all the ethernet connections, no problems (my desktop is connected via ethernet); there are also ~10 devices on the network at any given time, but they're not normally pulling data. The tech then said that even if a network is capable of putting out that higher download rate, it will still throttle to the speed of the slowest device. I'm still skeptical of that statement, but I'm looking to setup PfSense and use my existing router to help with the wifi portion. I already have the necessary hardware so I won't be spending any more money on it. Is this the best course of action to help stop the bottlenecking? Or is there something I'm not thinking of?
 

USAFRet

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Download speed could be (and often is) entirely dependent on the server or resource you are downloading from.

Not every server has the outgoing resources to feed everyone their theoretical max at all times.
Just like you have a 400mbps download limit, they have some upload limit. And they are feeding a LOT of people, not just you.
 
For consistency test with one of the speedtesting sites. These are designed for testing and since they run for only a short time do not put artificial caps on them like some file download sites do. You also have to be somewhat careful about which speedtesting location the tool chooses. If you play around with this you will find there are very different test speeds even within the same city. You need to consistently use the same test location for your results to be valid.

So if you systematically test where is the problem.

If you connect directly to the modem you get 450mbps.

Now what happens if you connect your router to the modem and then use a ethernet to connect your pc to the router. I would factory reset the router and then only set the admin and wifi passwords. Leave everything else on default to start with. This is to eliminate some feature on the router causing the issue.

If you still see a slow down with the router in the path then maybe it is the firmware on the router.


You have to be somewhat careful of using something like pfsense. A very simple router does the NAT function with a hardware assist. When you use fancy features on a router, like any form of firewall, the NAT function must be done by the CPU chip instead. This will bottleneck even very powerful routers to 250-300mbps.
Running something like pfsense on a actual pc will be better since the cpu is much more powerful but you must still be careful. Too many rules can slow down even a very fast machine.
 

Thought Provoker

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Download speed could be (and often is) entirely dependent on the server or resource you are downloading from.

Not every server has the outgoing resources to feed everyone their theoretical max at all times.
Just like you have a 400mbps download limit, they have some upload limit. And they are feeding a LOT of people, not just you.
I'm saying that I tested it via multiple speedtests. The download was just where I first noticed it. So I did speedtest.net once getting like 245 mbps, then I hooked my ethernet up to the modem directly and did speedtest.net again but got ~450 mbps. These two tests happened about 10 minutes between each other.
 

Thought Provoker

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For consistency test with one of the speedtesting sites. These are designed for testing and since they run for only a short time do not put artificial caps on them like some file download sites do. You also have to be somewhat careful about which speedtesting location the tool chooses. If you play around with this you will find there are very different test speeds even within the same city. You need to consistently use the same test location for your results to be valid.

So if you systematically test where is the problem.

If you connect directly to the modem you get 450mbps.

Now what happens if you connect your router to the modem and then use a ethernet to connect your pc to the router. I would factory reset the router and then only set the admin and wifi passwords. Leave everything else on default to start with. This is to eliminate some feature on the router causing the issue.

If you still see a slow down with the router in the path then maybe it is the firmware on the router.


You have to be somewhat careful of using something like pfsense. A very simple router does the NAT function with a hardware assist. When you use fancy features on a router, like any form of firewall, the NAT function must be done by the CPU chip instead. This will bottleneck even very powerful routers to 250-300mbps.
Running something like pfsense on a actual pc will be better since the cpu is much more powerful but you must still be careful. Too many rules can slow down even a very fast machine.
Yeah, I should've been more specific. To clarify, I did use speedtest.net to test the speeds; you can see my reply to USAFRet. But as for hardware, I have a regular i3 from like 2016 that I had lying around with 8GB of RAM so the computer is overkill, I'd just be using the router for the wifi portion. I haven't tried the factory resetting, I'll look into that.

EDIT: I tried resetting my router and it worked. Something about switching it back to default settings brought back the download speed to 460 mbps.
 
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That is not uncommon. Any feature that requires the CPU chip to see the traffic disables the NAT hardware accelerator. So now the CPU chip must do whatever function you turned on in addition to the NAT. It is very common to cap even a fairly powerful router at 300mbps because the cpu in router is so small.

In effect when you have a fast internet connection you can not use fancy feature on the router. It would be nice if they popped up a big box saying it was disabling the hardware assist. Some are not very obvious since the traffic bypasses the cpu even something simple like utlization reports by ip would require the cpu to see the traffic.
 
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