Question Fluctuating internet speed

atahann17

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Aug 4, 2020
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I have 100 mbps download speed with FTTB. My internet speed is fluctuating so much since I changed my router. I tried turn back the other router that worked fine but the problem is still ongoing. So I'm thinking if I damaged the cat6 cable while replacing the router. It is possible? My ISP says there is no problem on their side. I will add gifs that describe the speed fluctuation problem very well.
Before the problem started, I could not see a speed value above 100 mbps. Now it is fluctuating like that.

Here is steam download speed.




Here is a result from a speedtest site. As you can see on the graph, it is fluctuating so hard.
 
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I would not trust steam as a testing tool. It seems to do what it wants. I am not sure if that is because some games it downloads in chucks or if there is something else about how it runs. I see huge varaiations in steam download all the time and it seem to even be different between different games.

I have not seen the speedtest site you are using before. Does the blue line mean it gets really fast download and then basically nothing.

That very well could be a bad cable. It is not very likely but it could be. A cable does not actually run at slower speeds. You cable is likely transferring the data between the router and the pc at 1gbit all the time. The issue would be if the packets are damaged the data is discarded. The end application must retransmit the data and this slows things down. So from a application viewpoint it would be slower transfer but data loss on the cable.

I would first try a constant ping to the router IP but it may not show anything if the problem is load related.

I would then run a steam download and run your ping. I will assume you have a router with gigabit lan ports. This means even if you were to download at your full ISP rate of 100mbps you would still have enough bandwidth to ping the router.

You might see tiny changes in the latency buy you should not see packets loss
 

atahann17

Prominent
Aug 4, 2020
4
0
510
0
I would not trust steam as a testing tool. It seems to do what it wants. I am not sure if that is because some games it downloads in chucks or if there is something else about how it runs. I see huge varaiations in steam download all the time and it seem to even be different between different games.

I have not seen the speedtest site you are using before. Does the blue line mean it gets really fast download and then basically nothing.

That very well could be a bad cable. It is not very likely but it could be. A cable does not actually run at slower speeds. You cable is likely transferring the data between the router and the pc at 1gbit all the time. The issue would be if the packets are damaged the data is discarded. The end application must retransmit the data and this slows things down. So from a application viewpoint it would be slower transfer but data loss on the cable.

I would first try a constant ping to the router IP but it may not show anything if the problem is load related.

I would then run a steam download and run your ping. I will assume you have a router with gigabit lan ports. This means even if you were to download at your full ISP rate of 100mbps you would still have enough bandwidth to ping the router.

You might see tiny changes in the latency buy you should not see packets loss


This is my traceroute when I run fast.com test. My ping jumps too high, also I see packet loss almost every hops.

Packet loss in the router should be ignored. it always like that.
Also, in all the speedtest sites or sites that you can download any file, I get same result.
Must say, The packet loss thing was still happening when I dont have any problem with my speed, which is 1 week ago.
 
I would try to connect it without your router directly into a modem if that is a option.

Mostly because this does look like a issue with the ISP. If it really was your router you would see loss in hop 2 also. This is mostly to so the ISP does not try to use that as a excuse to not try to fix this.

Unlike many people that post these on this forum this is exactly what pingplot that shows a loss is suppose to look like. It show issue starting at hop 4 and continuing all the way to the end with similar or larger loss including the final hop.

This mean there is some issue with the router at hop 4. Since the latency is still pretty consistent this likely is not a overload issue it is more likely some defective piece of equipment.

Now the big issue is getting the ISP to fix this, you have actually done a lot of the work to point them in the correct direction. The problem is the level 1 tech you talk to at the ISP likely only has training and access to help you with stuff in your house and the connection to your house...ie hop 1 and hop 2. You are going to have to find a way to get the tech to escalate your issue to the guys who can fix this. It likely affects all the people that live around you.
 

atahann17

Prominent
Aug 4, 2020
4
0
510
0
I would try to connect it without your router directly into a modem if that is a option.

Mostly because this does look like a issue with the ISP. If it really was your router you would see loss in hop 2 also. This is mostly to so the ISP does not try to use that as a excuse to not try to fix this.

Unlike many people that post these on this forum this is exactly what pingplot that shows a loss is suppose to look like. It show issue starting at hop 4 and continuing all the way to the end with similar or larger loss including the final hop.

This mean there is some issue with the router at hop 4. Since the latency is still pretty consistent this likely is not a overload issue it is more likely some defective piece of equipment.

Now the big issue is getting the ISP to fix this, you have actually done a lot of the work to point them in the correct direction. The problem is the level 1 tech you talk to at the ISP likely only has training and access to help you with stuff in your house and the connection to your house...ie hop 1 and hop 2. You are going to have to find a way to get the tech to escalate your issue to the guys who can fix this. It likely affects all the people that live around you.
Also I forgot the say someting important. Speed is not fluctuating if I select "single" connection mode on speedtest. Also if I set my router's ethernet port "fast" it does not fluctuate again. Problem is happening only when I use gigabit ethernet mode.
 
That is strange.

The pingplotter you ran clearly shows you have a network problem.

Not sure what you are changing on the ethernet. If you are setting it to 100mbps then maybe there is a cable issue. It is fairly cheap to try a new cable. Make sure you get a quality cable. You only need cat5e but be sure the cable is pure copper (no CCA) and has wire size 22-24 (none of that flat or thin cable).

Now this would explain packet loss to the router but does not explain the network loss you see. If you showed packet loss in hop 2 and hop 3 then I might think there was a real issue in hop 1. If hop 1 causes problems it will cause problems in every hop past it. What you will see is exactly like hop 4 and past but it would start in hop 1 instead.
 

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