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Internet Speed Sudden Drop in Performance

Last response: in Networking
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November 28, 2012 10:51:11 PM

So, sometime ago, around about the start of November, my internet speed dropped out of nowhere, and has remained at the constantly lowered speed since then. Usually, I would have a download speed of 4/5 mbps, however, in recent days that's more like 1/2mbps. When trying a bandwidth test, that would usually have been about 3.6/3.7 mbps, however that is more like 1.6 mbps now. (A way I used to scope what my bandwidth was, was using the Formula1.com website where when you watch a video on it, it will tell you your bandwidth rating before hand. That, as I say, has dropped from the 3.6mbps to the 1.6mbps mentioned. This is normally an okay speed to do things, however, whilst my father is using Netflix, the internet becomes so slow, that it is basically impossible to do anything. Normally, on my 'old' internet speed, it would have not been a problem.

Now, I've done all the tests that are normally mentioned to do, as I have been searching for an answer since the internet speed tanked. It is not a computer specific problem as it is exactly the same on all devices connected to the router. I have rung my ISP, and they have said that my line should be receiving around 5/5.5mbps, as we run on an ADSL connection. However, doing a line test through the same provider says we should be getting 2.27 mbps. My ISP reports no problems with the line, and there has been no change at my end either.

When the internet suddenly dropped (as I say, it was a sudden speed decrease, it didn't happen over a period of time, it literally happened in an instant), I was on a BT HomeHub 2. This hub would continuously be disconnecting due to a fault, however, the internet speed was always at the 3.6/3.7 mbps (Bandwidth). However, around about the 4th-11th of November, as I say, the internet just dropped, but we were still having troubles with the disconnections. A BT HomeHub 3 was then upgraded to, which has since stopped the disconnections, but the speed has remained exactly the same.

Any advice would be appreciated on this, and I thank you for any time that you put into this issue. I just hope that it's something that can be resolved. I just want to know what has caused it, it's one of those things that just shouldn't happen, but has, and it is mighty frustrating.

Again, thanks. Phil
November 29, 2012 1:49:01 PM

This really sounds like something only your ISP can fix -- you need to be forceful and demand that they actually come out and test your line. They never want to do that, but they will if you are insistent.

Have it set up as simple as possible when they come, like a computer connected directly to the modem so that they don't try to blame it on your network, which you know is not the issue.
November 29, 2012 7:51:42 PM

Thank you RealBeast for the reply.

I think you may be right. I'll attempt to get hold of them again. Although, for arguments sake, say there isn't a fault, what else could it be?

Thanks, Phil.
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November 29, 2012 8:59:57 PM

You can look at a few things. First since you have a BT HomeHub 3, I believe that DECT wireless phones are incompatible, while they were compatible on the version 2 -- so check that you are not using DECT phones. Has anyone altered the data/DSL splitter on the line coming in; I've never heard of them "going bad" but have seen a few that were broken when a desk was set on top, although those totally quit working.

Any telephone line changes in the house? If any line changes were made and if good gel caps weren't used for the connection to the DSL line outlet you could get signal loss.

Also, you might want to run pingtest.net to see if you have any dropped packets, we wouldn't know why but that would indicate a line issue.

I would open the router configuration page by entering its gateway address into an attached computer and check the WAN settings. Since you have ADSL, and it is likely a PPoE connection. Check the MTU setting: the maximum allowable packet size (MTU) is 1492 bytes, but the optimal MTU size is 1454 bytes.

In the end in my experience with a number of DSL providers it always turned out to be a line issue. Can they tell you how far your connection is from the central station? I had one poor DSL connection that turned out to be over 17 thousand feet from the CO, which was 2000 feet over their capability, but they were able to re-route and repair the issue.
November 30, 2012 6:14:23 PM

Again, thank you for the reply, and also my apologies at taking a while to respond.

There have been no changed to the DSL on the line coming in, as far as I am aware. And there have been no changes to the telephone line in the house.
I did a test using pingtest.net, and I lose no packets.
I'm unable to find the MTU settings on the HomeHub Manager, however I've been informed that it always runs at 1500. Is that correct?
My distance to the like is 3km, so about 9900 feet, so that would be around 5000 feet within the capacity?

Is it possible that if one device on the network had a virus, that the entire network would run slower?

Thanks, Phil
November 30, 2012 6:19:47 PM

Also, here is the information I get about my ADSL connection from BT HomeHub Manager.

I get these results under the ADSL Connection Information:

Connection information
Line state: Connected
Connection time: 0 day, 21:12:47
Downstream: 2,268 Kbps
Upstream: 1,156 Kbps

ADSL Settings:

ADSL settings

VPI/VCI: 0/38
Type: PPPoA
Modulation: G.992.5 Annex A
Latency type: Interleaved
Noise margin (Down/Up): 7.8 dB / 5.4 dB
Line attenuation (Down/Up): 41.0 dB / 23.3 dB
Output power (Down/Up): 0.0 dBm / 12.6 dBm
FEC Events (Down/Up): 775193 / 5955
CRC Events (Down/Up): 91 / 948
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
HEC Errors (Down/Up): 53 / 1597
Error Seconds (Local/Remote): 0 / 288
November 30, 2012 6:43:18 PM

McPhilen said:
Again, thank you for the reply, and also my apologies at taking a while to respond.

There have been no changed to the DSL on the line coming in, as far as I am aware. And there have been no changes to the telephone line in the house.
I did a test using pingtest.net, and I lose no packets.
I'm unable to find the MTU settings on the HomeHub Manager, however I've been informed that it always runs at 1500. Is that correct?
My distance to the like is 3km, so about 9900 feet, so that would be around 5000 feet within the capacity?

Is it possible that if one device on the network had a virus, that the entire network would run slower?

Thanks, Phil
Ethernet uses a 1500 byte packets (an MTU of 1500), ADSL with PPPoE uses at most 1492 due to an 8 byte overhead requirement.

The only way that a virus on one device would slow the whole network would be if it did something that used bandwidth.
November 30, 2012 6:46:32 PM

I see. I did an MTU check thing and it came out to 1492, so you were spot on with what mine is.

Also, is there any way to check if a virus is using bandwidth? Or should I just manually check each device for any viruses?
November 30, 2012 7:08:31 PM

McPhilen said:
I see. I did an MTU check thing and it came out to 1492, so you were spot on with what mine is.

Also, is there any way to check if a virus is using bandwidth? Or should I just manually check each device for any viruses?
Check each device, but your BT stats show your up and down speeds, which look pretty low.
November 30, 2012 8:18:24 PM

Is it possible the speeds of both up and down are hampered by a virus, or is that an ISP thing? As in, is this the service speed I should be receiving, because it's lower than what it used to be. Are they allowed to just cut speeds?

Also, thank you for all the help. It is genuinely appreciated.
November 30, 2012 8:37:37 PM

It is extremely likely that it is either an ISP cut or their is some line issue beyond your home that is the problem. They will never tell you and always try to avoid coming out to fix the issue in my experience with a number of different DSL providers. And compounding the problem is that their tech support people are generally not very knowledgeable, often reading from scripted Q and A pages. To get it fixed you need to get them out to your house and/or elevate the support to a higher level supervisor or real technician.

You should get what you pay for, so if your service is 5Mbps down that is what you should get, nothing less. And I have found that ISPs will often give a refund for periods of poor service.
December 1, 2012 8:17:54 PM

How would I go about acquiring support from a 'higher level' supervisor? Just ask when I talk to the regular support people? I rang today and they came back with 'change the channel on your hub.' (Well, my father rang, and he just accepted the 'solution' and moved on. Obviously this didn't work and is something I have tried many a time. I'll be ringing them on Monday, so was just wondering for advice on how to approach them.
They also said, there's no problem with the line, which is either a lie, they don't know how to fix it, or they don't want to admit a cut. Or is this an unfair assumption?

Again, thank you.
December 1, 2012 8:31:38 PM

Tell them what your plan speeds are supposed to be, but that your BT Home Hub says that you are only getting 2.2Mbps down and 1.1Mpbs up speeds. Ask them what they can do to improve those speeds that will not cause significant instability.

With ADSL, and I assume that you have ADSL2+, there is often a trade off between speed and reliability. Obviously you want both and only you can decide the best balance for you, so whatever they can do to enhance your signal, improve (or at least don't diminish too much) your signal to noise ratio and increase speed is what you want them to figure out.

Are there any filters or signal boosters that they can provide to maintain reliability but increase speed. Offer to talk to a higher level tech support if they cannot make such changes.

And last, do they have any better plans that may cost a bit more but will give you a lot more?
!