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Standard User Orddu
(newbie) Sun 11-Mar-12 11:18:44
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FTTC speed problem after modem replacement


[link to this post]
 
Last weekend we had the chap come to swap out the BT modem on our fibre. Fibre is with Zen internet.

Prior to this, we were getting ~32 meg out of it, according to the thinkbroadband and several other speed testers.

After he went, it had dropped immediately (10 mins after he left) to 18 meg. "OK," we thought, "it needs a little think."

But a week passed and it's no better. We spoke to Zen yesterday about it. They got us to run the BT speed tester, which reports 36 meg. I'm not sure exactly what that tests or how. Anyway, we're still only getting 18 meg as far as we can tell, from 4 testers on various continents, and from the reported speed of files being downloaded. It is noticeably slower than before, when we used to download a 30-min podcast in ~30 seconds, and now it's ~50.

Zen also took the Netgear router out of the equation by connecting us briefly directly to that BT modem. Still 18 meg. At this point they told us that since the BT checker reports 36, BT won't touch it or see it as a fault. Game over, although they've turned on the ping response in our router to watch it for a couple of days.

Taking matters into our own hands, we've also swapped the wall-to-BT-modem cable with one from next door's house (no change). We took our new BT modem to a friend's house (who gets ~34 meg out of his) and tried it there, and his speed was unchanged so it's not the modem either. We get about another 0.5 meg out of it if we unplug the phone from the same socket, but that's all. There's no internal phone wiring in the house from that socket, and we're not using wireless off of it either. Just wall-master socket-modem-router-single PC, ethernet-wired. It's no different if we have the rest of the house network plugged in, to be fair.

As far as I can tell, this leaves either a fault in the master socket, or something occurred when that modem was swapped which has got something stuck somewhere along the line. As I pointed out to Zen, it's a huge coincidence that this happened immediately after the engineer came.

If anyone has any ideas of anything else to try, or something to tell Zen to do, we would be most grateful. BT fault or not, it seems obvious to me that with 36 meg being "delivered" but only 18 meg being "useable", something somewhere is blocking 50% of our bandwidth.

Open to suggestions!
Standard User Zadeks
(committed) Sun 11-Mar-12 11:59:45
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
Post a screenshot of the result from the BT java speedtest.
Standard User Orddu
(newbie) Sun 11-Mar-12 12:23:26
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Re: FTTC speed problem after modem replacement


[re: Zadeks] [link to this post]
 
I presume this is the one at speedtester.bt.com?

Interestingly, I ran it and it said 16 meg the first time!! Then I ran it again immediately and it said 36 meg.

First and second ones

Then I remembered that it doesn't like Chrome very much (doesn't give the little graph thing) so 3rd one is 3 mins later again, on IE.

3rd one

So that's the 3 replies in the space of 5 minutes tops. The first one is particularly interesting since that's the first time we've seen it say anything other than 30+

If that's not the test you want, could you point me to it please?


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Standard User BatBoy
(legend) Sun 11-Mar-12 12:36:46
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
IP profile for your line is - 38.71 Mbps
This means there is nothing wrong with your connection. I guess Zen is capping your speed.



______________________________________________________________________________. __________________
Standard User Orddu
(newbie) Sun 11-Mar-12 12:48:12
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Re: FTTC speed problem after modem replacement


[re: BatBoy] [link to this post]
 
Hmm, I imagine that's by accident and not on purpose, otherwise the tech guy yesterday would have mentioned it.

Or not...

But they don't have (or say they don't have) any capping, shaping or whatever.

Weirder and weirder...
Standard User Orddu
(newbie) Sun 11-Mar-12 13:39:23
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
We've also just been and kidnapped our friend's entire BT modem and cables and just tried that as well. No change there either.
Administrator MrSaffron
(staff) Sun 11-Mar-12 13:58:49
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
Congestion on WBC link maybe.

Do speeds improve at the quieter times e.g. breakfast 7 am to 9am

Andrew Ferguson, [email protected]
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User Orddu
(newbie) Sun 11-Mar-12 14:02:21
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Re: FTTC speed problem after modem replacement


[re: MrSaffron] [link to this post]
 
Alas not, we've tried at all hours, morning, midday, evening, middle of the night even. Always around the same mark.

Zen's service details on their site swear blind they don't cap speeds or traffic shape in any way.

Don't know what to say to them next, really. frown
Standard User RobertoS
(sensei) Sun 11-Mar-12 14:11:00
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
Which PSU is being used by you and your friend? The old black one or the new white one?

This could be a complete red herring, but the new modem claims to need 1A supply, which the white one is rated at. The old PSU is rated at 0.6A and the old modem was 0.7A requirement.

BT appparently, and some good figures from a couple of posters, say the black one should cope. But it is worthwhile ruling out the possibility here that it can affect the throughput.

My broadband basic info/help site - www.robertos.me.uk
My domains,website and mail hosting - Tsohost. Internet connection - Plusnet Value Fibre.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
Standard User Orddu
(newbie) Sun 11-Mar-12 14:52:41
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Re: FTTC speed problem after modem replacement


[re: RobertoS] [link to this post]
 
We both have the black ones with 0.6 written on them. We've tried both, and both in different mains sockets.

I suppose that could mean that our modem just doesn't like the 0.6 but his one does... we don't have a white one to try. When the neighbours come home, we'll see what colour theirs is and try to nick it if it's white wink

We've used his PSU on his modem on our line, and his PSU on our modem on our line. Neither made any change.
Standard User RobertoS
(sensei) Sun 11-Mar-12 16:39:01
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
I assume you still have a dangly filter from ADSLx days. There is nothing to stop you removing the VDSL2 faceplate and using that into the test socket. See how that does.

My broadband basic info/help site - www.robertos.me.uk
My domains,website and mail hosting - Tsohost. Internet connection - Plusnet Value Fibre.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
Standard User Orddu
(newbie) Sun 11-Mar-12 16:58:31
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Re: FTTC speed problem after modem replacement


[re: RobertoS] [link to this post]
 
Oh we certainly have - if nothing else from the bog-standard ADSL backup at the bottom of the stairs smile

When my glamorous assistant gets back, I'll set him on it. Thanks for the idea!
Standard User kasg
(experienced) Sun 11-Mar-12 17:21:26
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
I don't understand how most of these suggestions are relevant if the BT speed tester (which is always the worst of the lot for me) is showing 36Mbps.

Kevin

plusnet Extra 80/20 trial
My Broadband Speed Test
Using OpenDNS
Standard User Orddu
(newbie) Sun 11-Mar-12 22:19:10
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Re: FTTC speed problem after modem replacement


[re: kasg] [link to this post]
 
BT speed tester says 36 meg is being pumped out to us.

Until last weekend, in the house we could utilise about 30 meg of that 36.

Since last weekend, we can only utilise 18 meg of it. This is verified by other non-BT speed-testers, downloads, etc.

The in-the-house speed has demonstrably dropped.

We have eliminated (apart from the modem PSU) every piece of kit this side of the master socket hole in the wall.

Something is preventing us seeing more than half of what BT says its delivering to us.

Therefore something somewhere is either lying to us, is misinformed or is confused. But whatever else, downloads we do the same each week which used to take 30s now take 50s, regardless of time of day. This is commensurate with a useable level of 18 and not ~30 meg.
Standard User Squirrel
(knowledge is power) Sun 11-Mar-12 22:30:33
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
In reply to a post by Orddu:
Therefore something somewhere is either lying to us, is misinformed or is confused. But whatever else, downloads we do the same each week which used to take 30s now take 50s, regardless of time of day. This is commensurate with a useable level of 18 and not ~30 meg.

It may or may not be related to your problem but about a month ago speedtest.net was saying my download speed was only 23Mbps rather than the usual 38Mbps.

I went round the whole check the connections, recycle modems, routers but no matter what I tried I got 23Mbps.

A little bit later I was on another machine in my house, a rather smaller HP Microserver and I got the usual 38Mbps. Thinking whatever had been the problem had resolved itself I tried again on my main server - 23Mbps. Seemed to point at my main server as being the problem, network card failing or something.

I tried a different browser, Chrome and got 38Mbps, IE9 was 38Mbps, FF10 (I think) 23Mbps. So a problem with FF on one particular machine. Deleted and reinstalled FF and straight back up to 38Mbps where it has remained ever since.

No idea exactly what the problem with FF was, but it was indeed a FF problem - nothing to do with my connection at all.

Standard User asbokid
(regular) Sun 11-Mar-12 22:41:45
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Re: FTTC speed problem after modem replacement


[re: Squirrel] [link to this post]
 
In reply to a post by Squirrel:
No idea exactly what the problem with FF was, but it was indeed a FF problem - nothing to do with my connection at all.

Firefox (and the Flash plugin) was perhaps configured to connect through a proxy.
And that added a considerable overhead to the speedtest results?

cheers, a
Standard User Orddu
(newbie) Sun 11-Mar-12 23:13:51
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Re: FTTC speed problem after modem replacement


[re: asbokid] [link to this post]
 
Tried on 3 different machines, Chrome, IE9 and FF. All roughly the same results (variation very small).

This is the same whether the internal network is connected, or whether it goes wall socket > modem > PC (Zen even took the router out of the equation yesterday and we connected straight into the modem briefly).
Standard User RobertoS
(sensei) Mon 12-Mar-12 00:07:19
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Re: FTTC speed problem after modem replacement


[re: kasg] [link to this post]
 
In reply to a post by kasg:
I don't understand how most of these suggestions are relevant if the BT speed tester (which is always the worst of the lot for me) is showing 36Mbps.
I agree with you in theory, but
When you have eliminated every possibility, whatever is left, no matter how impossible must be true
A principle I frequently found true in relation to computing and data networks.

My broadband basic info/help site - www.robertos.me.uk
My domains,website and mail hosting - Tsohost. Internet connection - Plusnet Value Fibre.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
Standard User Orddu
(newbie) Mon 12-Mar-12 09:51:16
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Re: FTTC speed problem after modem replacement


[re: RobertoS] [link to this post]
 
We've also had the faceplate off the master socket and connected with a microfilter to the phone socket inside. Still no change, so it's not that either.

Which leaves something shonky with BT or something shonky with Zen really. Everything our side of the BT wiring has been eliminated.
Standard User MHC
(legend) Mon 12-Mar-12 10:07:01
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
Have Task Manager running with the network tab selected.

Run te following tests:

BT Speedtester
BT Beta Speedtester (twice) http://speedtest.btcentralplus.com/beta/
TBB Java
TBB Flash
Speedtest.net - Best server and then another UK of your choosing

Take a screen shot of the Task Manager window and post a link to the image.





~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


M H C


taurus excreta cerebrum vincit
Standard User Orddu
(newbie) Mon 12-Mar-12 16:20:30
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Re: FTTC speed problem after modem replacement


[re: MHC] [link to this post]
 
Results of the tests

These were run one after another in the space of a few minutes from 12pm today.

The main BT one shows 19 meg coming down.

The speedtest.net ones were most interesting. The "best" one showed almost 37 meg, but the random one 25. Even 25 better than 18 though!

So I ran tracerts to those two servers to see what happened (they're at the end of the file). The first one to the random server had some long sections in it, but subsequently was OK.

This is starting to feel a bit route-ish to me now though... And not a peep out of Zen after I sent them all my findings first thing this morning. I'll go through the ticketting system again.
Standard User MHC
(legend) Mon 12-Mar-12 16:51:29
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
99.9% certain it is not inside your property and probably not a local noise issue. What you have shown is similar to another one I know of and that is proving very hard to track down or resolve.

It could be contention/congestion, possibly some form of throttling or maybe even a node somewhere that is having issues of its own.

One reason you could be getting a good 38Mbps BT speedtest followed by a bad 15-20 result is that there are TWO BT speedtest sites and under the same URL and you could be connected to either of them so if one route has an issue and the other clean it will explain why.

What to do? Ensure te case remains open with the ISP and keep checking with them and against your results.





~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


M H C


taurus excreta cerebrum vincit
Standard User Orddu
(newbie) Mon 12-Mar-12 17:02:34
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Re: FTTC speed problem after modem replacement


[re: MHC] [link to this post]
 
I'd love for it to remain open... but as yet they won't even log it because it's not a problem!

Emails have gone to and fro, but they're all very much along the lines of "we're pinging you to look for packet loss" and that any engineer would be chargeable.

This is fair enough, but I'm getting the *strong* impression (particularly from that tracert with the too-big numbers on the Zen network itself) that this is an internal problem they just haven't spotted yet.

If push comes to shove, our contract is up in May so we'll go through the other providers and see who's about. I really don't feel like anyone at Zen's taking this even remotely seriously at the moment. frown
Standard User jchamier
(knowledge is power) Mon 12-Mar-12 18:22:38
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
In reply to a post by Orddu:
If push comes to shove, our contract is up in May so we'll go through the other providers and see who's about.


AAISP still have their "we'll fix your line" offer - could be the sort of people you need for this.

Zen surely aren't living up to their reputation on this issue - I thought they were supposed to be "good" ?

James - be* pro - on THFB - sync about 17.2mbps - BQM
Standard User Orddu
(newbie) Mon 12-Mar-12 19:13:09
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Re: FTTC speed problem after modem replacement


[re: jchamier] [link to this post]
 
AAISP seem worth considering... although Zen say BT won't consider this as a fault as it's >12 meg.

Interestingly, if I go to the Infinity page to check whether I can get it, it says:

BT Infinity
Superfast fibre optic broadband
Great news! You are eligible for superfast BT Infinity.
32.0Mb download
5.8Mb upload


And then further down says:

BT always offers you the best speed possible on your line.The speed prediction we have given here is an estimate, however download speeds can vary and the actual download speed will fall within a range. The range is an indication of the speed that other similar lines across the UK have achieved for their broadband service; this is generally within 1-2 Mb higher or lower than your single estimated speed quoted.


So even BT think that it should be only 1-2 meg different from the quoted speed it shows. Which would be 30-34, 2 meg either side. Not **14** lower.

And no, Zen have always been good (and I recently voted for them) but I'm not impressed at the moment.
Standard User jchamier
(knowledge is power) Mon 12-Mar-12 22:58:02
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
In reply to a post by Orddu:
So even BT think that it should be only 1-2 meg different from the quoted speed it shows. Which would be 30-34, 2 meg either side. Not **14** lower.

And no, Zen have always been good (and I recently voted for them) but I'm not impressed at the moment.


I think Zen's "BT" is OpenReach (OR), whereas you've looked at BT Retail's product page (for Infinity).

Zen's supplier is OR and its likely in their contract with OR they have such a percentage.

James - be* pro - on THFB - sync about 17.2mbps - BQM
Standard User Orddu
(newbie) Tue 13-Mar-12 00:13:12
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Re: FTTC speed problem after modem replacement


[re: jchamier] [link to this post]
 
Ahh I see. Well, I shall poke them tomorrow then!
Standard User Orddu
(newbie) Tue 13-Mar-12 12:22:48
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
They're still quibbling with me. However, I did this:


I ran a tracert and I found that the first router we hit of Zen's is 62.3.84.21 so I set off a continuous ping to it and it came back (with no activity on the network) solidly at 23ms.

Then I set off a speedtest and it did this:

Reply from 62.3.84.21: bytes=32 time=23ms TTL=253 <-- no network activity
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253
Request timed out. <--start of speed test, the particularly worrying bit!
Request timed out.
Reply from 62.3.84.21: bytes=32 time=27ms TTL=253
Reply from 62.3.84.21: bytes=32 time=28ms TTL=253
Reply from 62.3.84.21: bytes=32 time=28ms TTL=253
Reply from 62.3.84.21: bytes=32 time=96ms TTL=253
Reply from 62.3.84.21: bytes=32 time=145ms TTL=253
Reply from 62.3.84.21: bytes=32 time=153ms TTL=253
Reply from 62.3.84.21: bytes=32 time=120ms TTL=253
Reply from 62.3.84.21: bytes=32 time=99ms TTL=253
Reply from 62.3.84.21: bytes=32 time=172ms TTL=253
Reply from 62.3.84.21: bytes=32 time=185ms TTL=253
Reply from 62.3.84.21: bytes=32 time=157ms TTL=253
Reply from 62.3.84.21: bytes=32 time=83ms TTL=253
Reply from 62.3.84.21: bytes=32 time=165ms TTL=253
Reply from 62.3.84.21: bytes=32 time=191ms TTL=253
Reply from 62.3.84.21: bytes=32 time=200ms TTL=253
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253 <-- pause to change from download to upload
Reply from 62.3.84.21: bytes=32 time=160ms TTL=253
Reply from 62.3.84.21: bytes=32 time=152ms TTL=253
Reply from 62.3.84.21: bytes=32 time=119ms TTL=253
Reply from 62.3.84.21: bytes=32 time=183ms TTL=253
Reply from 62.3.84.21: bytes=32 time=189ms TTL=253
Reply from 62.3.84.21: bytes=32 time=125ms TTL=253
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253 <-- end of speed test, no network activity
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253
Reply from 62.3.84.21: bytes=32 time=23ms TTL=253

I repeated this with a couple of sites and an FTP download from my own ftp space. Each one has at least 2 or 3 timeouts in it. This is borne out by the tracert I sent in yesterday which had the latency start at the same router.

Question is, would you expect this? Really, should you get packet loss and that sort of latency showing just from a simple download? The Zen person seems totally unconcerned at this, but 1st line support I guess.

Comments, anyone? Am I barking in the wrong forest?
Standard User Orddu
(newbie) Tue 13-Mar-12 13:31:17
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
Zen have now received this and are passing the situation on to the fibre team who will look at it tomorrow.

(Partial) result! smile
Standard User jchamier
(knowledge is power) Tue 13-Mar-12 13:41:16
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
In reply to a post by Orddu:
Question is, would you expect this? Really, should you get packet loss and that sort of latency showing just from a simple download? The Zen person seems totally unconcerned at this, but 1st line support I guess.


Yes - the speed test is flooding your line, maxing it out. If you max out a TCP/IP connection you will get packet loss.

James - be* pro - on THFB - sync about 17.2mbps - BQM
Standard User Orddu
(newbie) Tue 13-Mar-12 15:11:07
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Re: FTTC speed problem after modem replacement


[re: jchamier] [link to this post]
 
Would you expect that from a bog-standard FTP download from my ftp account as well though? I presume it's not as full-on as a speed test which yes, I can see would be trying to push it to its limits.

And the tracert yesterday, there wasn't anything else going on on our connection at the time I saw the high pings, which is more worrying.
Standard User jchamier
(knowledge is power) Tue 13-Mar-12 15:44:01
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
In reply to a post by Orddu:
Would you expect that from a bog-standard FTP download from my ftp account as well though? I presume it's not as full-on as a speed test which yes, I can see would be trying to push it to its limits.


In theory your FTP account can fill your line as well - but its possible your FTP provider limits the data rate, either per connection, or per IP address. This allows them to serve more people.

And the tracert yesterday, there wasn't anything else going on on our connection at the time I saw the high pings, which is more worrying.


It could also be that the routers don't bother to reply to your ICMP packets (from the traceroute) because they're busy doing real work.

James - be* pro - on THFB - sync about 17.2mbps - BQM
Standard User NICK_ADSL_UK
(fountain of knowledge) Tue 13-Mar-12 16:20:42
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
In reply to a post by Orddu:
Alas not, we've tried at all hours, morning, midday, evening, middle of the night even. Always around the same mark.

Zen's service details on their site swear blind they don't cap speeds or traffic shape in any way.

Don't know what to say to them next, really. frown


That is correct zen do not cap at all

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Standard User Orddu
(newbie) Tue 13-Mar-12 16:41:29
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Re: FTTC speed problem after modem replacement


[re: NICK_ADSL_UK] [link to this post]
 
I think our traffic is not so much shaped as mutated!

The tracert didn't have any which didn't respond, only ones which normally give ~23ms and suddenly started giving ~200ms responses, when our connection was otherwise inactive.
Standard User Zadeks
(committed) Tue 13-Mar-12 16:56:18
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
You should expect high latency and packet loss if you saturate the connection.
Standard User Orddu
(newbie) Wed 14-Mar-12 19:12:51
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Re: FTTC speed problem after modem replacement


[re: RobertoS] [link to this post]
 
OK, BT have now looked at it and confirmed that we sync at 36 meg as far as they're concerned.

Having tested all (*) the kit in the house, have passed it firmly back to Zen as a potential routing issue.

(*) But.

The only avenue we haven't explored is this potenial underrated PSU that you mentioned. The neighbours have had 5 new modems so far (I think the dog is eating them) but still have a black PSU - argh.

Networking I'm happy with, electrics less-so. Could you possibly point me towards a suitable higher-rated PSU I could buy and try out, please? If there's no change, pfft we tried. But it's the only thing we haven't had a go at and I like to be thorough. Plus we'd like to go to 80meg when it's available, but if it's overloaded at 40 then 80 ain't gonna help.

Ideally, "go into Maplin and ask for..." or a link to a mail-order site would be lovely smile

Thank you very much in advance!
Standard User kasg
(experienced) Wed 14-Mar-12 19:16:09
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
I would say forget the PSU, I don't see how it can be relevant if it was working perfectly well with the old modem. Assurance after assurance has been given that the PSU is adequate for the new modems.

Kevin

plusnet Extra 80/20 trial
Using OpenDNS
Standard User Orddu
(newbie) Wed 14-Mar-12 19:30:14
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Re: FTTC speed problem after modem replacement


[re: kasg] [link to this post]
 
Well, other than a small outlay it can't actually hurt, and it is the only piece of kit left in the equation. I'm willing to give it a try for the sake of completeness if nothing else. Cos if I find out later it was that, I'm going to feel like a right nana!
Standard User mr_mojo
(knowledge is power) Wed 14-Mar-12 19:59:09
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
Try a multithreaded download. A large DVD ISO of Linux on bittorrent, for example.
Standard User asbokid
(member) Wed 14-Mar-12 20:17:19
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
So your VDSL2 modem does work okay on a friend's line.. can you now borrow your friend's modem and try it on your line?

And just to satisfy yourself that the PSU is not the cause, maybe try your friend's PSU with your modem..

Who is telling you that your line is sync'ing at 36Mbps? BT but not Zen?

Since the Huawei, while locked, operates as a 'black box', you can't verify the sync speed yourself.

Can you source an unlocked modem temporarily?

cheers, a
Standard User jchamier
(knowledge is power) Wed 14-Mar-12 20:27:26
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Re: FTTC speed problem after modem replacement


[re: mr_mojo] [link to this post]
 
In reply to a post by mr_mojo:
Try a multithreaded download. A large DVD ISO of Linux on bittorrent, for example.


Or a download of the ISO for Windows 8 consumer preview 64bit - its 3.6gigabytes. Using the browser first, and then using a download manager (e.g. GetRight, free trial available http://www.getright.com/).

James - be* pro - on THFB - sync about 17.2mbps - BQM
Standard User kasg
(experienced) Wed 14-Mar-12 21:37:04
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Re: FTTC speed problem after modem replacement


[re: asbokid] [link to this post]
 
In reply to a post by asbokid:
Since the Huawei, while locked, operates as a 'black box', you can't verify the sync speed yourself.

You don't really need to do this, since the sync speed can be derived from the IP profile, which is known, by multiplying it by about 1.033.

Kevin

plusnet Extra 80/20 trial
Using OpenDNS
Standard User Bald_Eagle1
(member) Wed 14-Mar-12 22:22:41
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Re: FTTC speed problem after modem replacement


[re: kasg] [link to this post]
 
In reply to a post by kasg:
You don't really need to do this, since the sync speed can be derived from the IP profile, which is known, by multiplying it by about 1.033.


In principle, yes.

However, in practice, if the modem re-syncs "on the fly" (which usually only takes a few seconds), the PPP session is very often maintained, as is the IP address & BT's IP Profile/BRAS Rate.

A modem reboot, or a less severe disconnect & reconnect of the router will initiate a new PPP session that is required to update the IP Profile.

e.g. with a 39999 k sync speed, the IP Profile should be 96.79% (38715 k or thereabouts).

If the connection re-synced unnoticed at say 30Mb, unless a new PPP session was also started, the IP Profile would probably stay at 38715 k, leaving the user unable to understand why throughput speed has dropped drastically, yet BT Speed tests still report the full speed IP Profile.

This phenomenon can be seen with Plusnet connections. I see it regularly.
Connections with other ISPs may also be the same.

As BT's own SIN 498 document warns about this, I would assume Infinity connection IP Profile updates are handled correctly?
Standard User Orddu
(newbie) Wed 14-Mar-12 23:09:36
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Re: FTTC speed problem after modem replacement


[re: jchamier] [link to this post]
 
I have downloaded Windows 8 iso via both methods (browser and Getright).

Both report ~2.2MB/sec with very little variation or fluctuation. So that's roughly the 18 meg we've been getting.

Out of curiosity I ran my ping test to the gateway router we go through, during the download (second pass so it didn't affect those figures above).

At this point I'm not seeing any variation in the ~23ms ping times even when downloading. So, the big latencies I was seeing when running the speedtests are absent. Thus I would conclude from this that the download is nowhere near as stressing as the speedtests were, hence no latency.

However, that same ping is showing around 25-28% packet loss during downloading:

Reply from 62.3.84.21 bytes=32 time=22 ms
Requested Timed out.
Reply from 62.3.84.21 bytes=32 time=21 ms
Requested Timed out.
Reply from 62.3.84.21 bytes=32 time=23 ms
Reply from 62.3.84.21 bytes=32 time=21 ms
Reply from 62.3.84.21 bytes=32 time=20 ms
Reply from 62.3.84.21 bytes=32 time=23 ms
Reply from 62.3.84.21 bytes=32 time=22 ms
Requested Timed out.
Reply from 62.3.84.21 bytes=32 time=21 ms
Requested Timed out.
Reply from 62.3.84.21 bytes=32 time=20 ms

So, if we we're getting 25% packet loss whenever downloading, that would presumably mean also 25% of packet retransmissions. i.e. 50% overhead. And there you go, we've lost ~50% of our effective bandwidth... I think that maths is right?
Standard User kasg
(experienced) Wed 14-Mar-12 23:44:17
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Re: FTTC speed problem after modem replacement


[re: Bald_Eagle1] [link to this post]
 
In reply to a post by Bald_Eagle1:
However, in practice, if the modem re-syncs "on the fly" (which usually only takes a few seconds), the PPP session is very often maintained, as is the IP address & BT's IP Profile/BRAS Rate.

A modem reboot, or a less severe disconnect & reconnect of the router will initiate a new PPP session that is required to update the IP Profile.

Fair enough, but, as you say, easy to eliminate by rebooting the router.

Kevin

plusnet Extra 80/20 trial
Using OpenDNS
Standard User RobertoS
(sensei) Thu 15-Mar-12 00:17:57
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
So, if we we're getting 25% packet loss whenever downloading, that would presumably mean also 25% of packet retransmissions. i.e. 50% overhead. And there you go, we've lost ~50% of our effective bandwidth... I think that maths is right?
tongue Nope. Maths is wrong.

It's a geometric series. Off the top of my head I forget the formula that I learned somewhere around 1960, for the summation ... but google is my friend for later.

Forget percentages, think of 1000 packets, and if we have faultless delivery they take 1 second. Also ignore associated overheads.

But 250 are lost so require retransmission. And so on.

Those 250 retransmissions should take 0.25 seconds. But 62.5 are lost.
62.5 take 0.0625 seconds. But 13.125 are lost.

So far we have:-
1.00 secs- 750 packets
1.25 secs - 937.5 packets
1.3125 secs = 986.875 packets.
...
...

The (googled) formula for the sum is given on this Wiki page.
a = 1
r = 0.25

Allowing for the fact I may be too tired now, the sum of the time series seems to be 1.333 recurring or one and a third seconds.

The loss is one third of the bandwidth, not half.

My broadband basic info/help site - www.robertos.me.uk
My domains,website and mail hosting - Tsohost. Internet connection - Plusnet Value Fibre.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
Standard User Orddu
(newbie) Thu 15-Mar-12 01:13:28
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Re: FTTC speed problem after modem replacement


[re: RobertoS] [link to this post]
 
Ah OK then, thank you smile But still, quite a big number even if not half.

And so it goes... shall see what their second-line bloke has to say tomorrow.
Standard User mr_mojo
(knowledge is power) Thu 15-Mar-12 02:55:34
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
The reason I said use bittorrent instead of the windows 8 iso is that it will be coming from different networks; ie if a peering link to Microsoft CDN is overloaded somehow then the other sources will make up for it.

Give it a whirl...
Standard User Orddu
(newbie) Thu 15-Mar-12 12:48:12
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Re: FTTC speed problem after modem replacement


[re: RobertoS] [link to this post]
 
I'm starting to think Zen are victims of their own success, and their network can't cope. If I download something from their internal support site, I got 14.4 meg out of it today. That's not straying into the wider net whatsoever.

However, the repeated message I get is "it's within parameters for the product" and "it's working isn't it".

How they - or anyone - would be happy if BT say it's synced at 40meg and only 18 is useable I don't know. And not gradually dropping as more people come online, plummetting. If it was contention I would expect to see fluctuations in the day, but I'm not.

The call centre chap, when I said I was still seeing problems at 1am/2am, told me that maybe everyone on my sector is downloading torrents at that time of night, hence the contention. Bit weird they all started doing that at the same time on the same day, isn't it.

I suspect I'm also suffering from having the wrong sort of voice... frown

I have asked them to check the health of the router I suspect as being the culprit, which he *very* grudgingly agreed to pass to the infrastructure team.

Fed up with it now.
Standard User jchamier
(knowledge is power) Thu 15-Mar-12 18:15:50
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
In reply to a post by Orddu:
Fed up with it now.


Write to the press? e.g. PCPro magazine, or anyone who's given Zen Internet a customer service award.

James - be* pro - on THFB - sync about 17.2mbps - BQM
Standard User Orddu
(newbie) Thu 15-Mar-12 18:22:06
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Re: FTTC speed problem after modem replacement


[re: jchamier] [link to this post]
 
Highly tempted.

I have nothing left to try. The fact that downloading from a Zen server is just as bad even takes the "busy internet sites" out of it.

It *has* to be them, somewhere, surely.
Standard User DLS
(learned) Thu 15-Mar-12 20:29:04
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
Netalyzr might be worth a shot:

http://netalyzr.icsi.berkeley.edu

Although you're unlikely to to see full bandwidth to the US west coast, it might pick-up something and you can always use it to add to your voice.
Standard User Orddu
(learned) Fri 16-Mar-12 13:29:11
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Re: FTTC speed problem after modem replacement


[re: DLS] [link to this post]
 
There's a couple of "This port is blocked" things, and the only non-green is:

Network buffer measurements (?): Uplink 500 ms, Downlink is good
We estimate your uplink as having 500 msec of buffering. This level can in some situations prove somewhat high, and you may experience degraded performance when performing interactive tasks such as web-surfing while simultaneously conducting large uploads. Real-time applications, such as games or audio chat, may also work poorly when conducting large uploads at the same time.


I don't know what that means, whether it's an issue and, if so, what we can/need/ought to do about it!

Otherwise, all green. Including:

Network latency measurements (?): Latency: 98ms Loss: 0.0%
TCP connection setup latency (?): 110ms
Network background health measurement (?): no transient outages
Network bandwidth (?): Upload 1.7 Mbit/sec, Download 16 Mbit/sec
Standard User DLS
(learned) Fri 16-Mar-12 14:33:57
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
I just ran Netalyzr on my BT connection and it's able to max-out the uplink and downlink ("Upload 8.3 Mbit/sec, Download >20 Mbit/sec" - I monitored the download myself and saw 37).

So, in your case, your bandwidth is clearly being limited (OK, you knew that already). Apart from the download issue, is your upload on a 2-Mbit/s plan, or does your result indicated an issue with that too?

As for the uplink buffering, 0.5s is quite excessive; I usually see ~0.1s, wired or wireless, but I have seen higher numbers in noisy wireless environments. I'm assuming you're running with ethernet wired into the router to avoid the vagaries of wireless. I'm not sure whether the uplink buffering could have an impact on downloads; maybe if it's a symptom of a delay in the return path, then acknowledgment packets might be delayed to the point where downloads are throttled. It's worth pointing it out to your ISP.

Otherwise, as MHC said early on, it's almost certainly outside your network and somewhere in the ISPs.
Standard User hareng
(learned) Fri 16-Mar-12 16:11:15
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
I have had exactly the same trouble for a few months but far far worse, sub 20k (sub dial up) totally variable to 37meg.
I thought mine was a routing issue, pages often timed out.

Just try cleaning registry, there are some free ones plus other cleaners etc.
I have done nothing else and no help from ISP who stated a service is being provided however fast.
Standard User Orddu
(learned) Fri 16-Mar-12 18:00:34
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Re: FTTC speed problem after modem replacement


[re: DLS] [link to this post]
 
Yes it's all wired. Well, beloved is wireless, but I don't let him test anything smile

Our upload is usually about 1.6 meg actual, and is max 2 meg according to the BT IP Profile. So that's happy enough.

I've had a snuffle around the router (Netgear WNR2000v2 - which has had a firmware update in the middle of all this, same before and after) to see if there's anything to do with prioritising and there is a QoS setting to prioritise certain data, but it's off.

I shall have to read up on buffering, then.

Any Zen users out there care to run the same test and give their results, at all?
Standard User DLS
(regular) Fri 16-Mar-12 18:27:44
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
Oversized buffers are a big problem for internet performance - see http://www.bufferbloat.net/projects/bloat/ as a starting point.

This could be a red herring, given that your problem started with new modem; run netalyzr again to confirm it and let your ISP see it.

Big buffers sometimes live in routers and it's good to see that you have QoS off. Although it seems likely to be outside your net, Windows is a dark pit so far as I'm concerned; if you're running that, then I think there are tuning tools available and others here might be able to offer advice. Otherwise, try something with a comprehensible network stack (*N*X-based) smile.
Standard User RobertoS
(sensei) Fri 16-Mar-12 23:30:53
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
tongue
You have to stop asking questions now. Your official status has changed from newbie, (Thursday 18:22), to learned, (Friday 13:29)!

Time for us to start asking you about our problems smile.

My broadband basic info/help site - www.robertos.me.uk
My domains,website and mail hosting - Tsohost. Internet connection - Plusnet Value Fibre.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
Standard User asbokid
(member) Sat 17-Mar-12 00:36:14
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Re: FTTC speed problem after modem replacement *DELETED*


[re: DLS] [link to this post]
 
Post deleted by asbokid
Standard User asbokid
(member) Sat 17-Mar-12 00:36:45
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Re: FTTC speed problem after modem replacement *DELETED*


[re: asbokid] [link to this post]
 
I was going to suggest that! Maybe the OP could boot one of the Linux Live CDs - e.g. Knoppix or Ubuntu in 'Try Me' mode.. just to eliminate Billygatesware as the cause.

cheers, a
Standard User Orddu
(learned) Sat 17-Mar-12 01:43:06
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Re: FTTC speed problem after modem replacement *DELETED*


[re: asbokid] [link to this post]
 
Well, as a quick test I've put the speedtest.net app on my Android phone. OK it's WiFi but it's also Windows-free, and lo and behold, 17.9 meg and 18.2 meg on 2 tests, network otherwise idle.

So it's not Windows then (which I didn't think it was, having used 3 laptops and a desktop on a variety of XPs and Win7s).

Plus we already have a Linux server, but it just sits there and looks after media files and backups, so I've not toyed with it. It has been known to be temperamental and probably needs an update, but currently it ain't broke!
Standard User DLS
(regular) Sat 17-Mar-12 09:46:27
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Re: FTTC speed problem after modem replacement *DELETED*


[re: Orddu] [link to this post]
 
I wouldn't necessarily rely on a phone+WiFi test. I've just tried my iPhone using our two access points with 802.11n (on the router) and 802.11g at the other side of the house, and it's not a great indicator of download performance.

802.11n peaked at ~27 Mbit/s within ~1 metre of the router, clear line-of-sight, and drops quickly to ~15-18 Mbit/s as I moved to ~2 metre. 802.11g managed 22 Mbit/s on one test, then ~16-18 on half-a-dozen more in the same spot next to the AP, although it maintained that to about 7 metre and through a couple of solid walls. Wired download speed on a desktop, before and after, is 37-38 Mbit/s.

If possible, it would be useful for you to calibrate the phone speed on another system that is known to have faster download speed.
Standard User DLS
(regular) Sat 17-Mar-12 10:03:41
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Re: FTTC speed problem after modem replacement *DELETED*


[re: asbokid] [link to this post]
 
In reply to a post by asbokid:
I was going to suggest that! Maybe the OP could boot one of the Linux Live CDs - e.g. Knoppix or Ubuntu in 'Try Me' mode.. just to eliminate Billygatesware as the cause.


I know how you feel. Apart from one or two irritating cases out of my control, I've largely managed to avoid the stuff. I suppose these days it's mostly harmless, but it's what I call "a rat in the bread bin"; I'm sure you'll get it after a minute of contemplation.
Standard User Orddu
(learned) Sat 17-Mar-12 12:15:27
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Re: FTTC speed problem after modem replacement *DELETED*


[re: DLS] [link to this post]
 
Oh indeed, not a hard-and-fast test, but it was all I was really up for at almost 2am!

And either way, a massive coincidence that it came up with the exact same answer as I've had from every other test so far. It might not be empirical data, but I think it's fair to say it eliminates Windows as the problem. Which 4 different installations already did, really, but it's nice to get it totally out of the equation.

Oh, and I was 6 feet from the wireless router, line-of-sight, same room smile
Standard User Zadeks
(committed) Sat 17-Mar-12 13:01:01
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Re: FTTC speed problem after modem replacement


[re: hareng] [link to this post]
 
A registry cleaner isn't going to do anything positive.
Standard User Orddu
(learned) Sat 17-Mar-12 13:21:37
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Re: FTTC speed problem after modem replacement


[re: Zadeks] [link to this post]
 
Nor will one ever come within 100 yards of any PC I have jurisdiction over!

But it's not possible for 4 PCs to suffer the same mental-health problem all at one moment, independently of one-another (especially on different OSs) so indeed, not going to help anyway.
Standard User Orddu
(learned) Thu 29-Mar-12 07:53:38
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
In the continuing saga...

Nothing changed until 01:19 this morning when the fibre went off. Hadn't come back 20 mins later, so we swapped to the backup ADSL and went to bed.

This morning, it was back on. And... showing 34 meg!!! Hallelujah!

However, in the time it took me to get dressed and have some cereal, it's back to 17.9 again.

A few moments of excitement there, but surely since it flashed to 34 for a few minutes and then retrained, surely SURELY someone must accept this as a fault now? Surely?!
ISP Representative Azzaka
(isp) Thu 29-Mar-12 09:39:23
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
I have spoken to Orddu this morning and we agree there is an issue there somewhere, however we are still trying to pin point where.

When it comes to the FTR (Fault Threshold Rate) set by OR, this is across the board no matter who the provider is. The BT Infinity estimate fluctuations of 1-2mb is for the provision of the fibre connection. So if they suggest you will receive 32mb. if they provide you with 30mb, they are still within limits. If however the speeds drop to 14mb, then it is still above the FTR of 12mb and therefore not classed as a fault (this is of course if they are running by the same rules as other providers.)

Leo Goile
---
ZeN Internet
Technical Support
ZeN are recruiting! Click here to view the opportunities available.

I Sync', I Auth', therefore I am.
Online

Edited by Azzaka (Thu 29-Mar-12 09:40:02)

The above post has been made by an ISP REPRESENTATIVE (although not necessarily the ISP being discussed in the post).
Standard User smurf46
(member) Thu 29-Mar-12 09:53:27
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Re: FTTC speed problem after modem replacement


[re: Azzaka] [link to this post]
 
Exactly what I thought! So all this marketing hype about "superfast", which usually means BT-based FTTC (VDSL2) is where a minimum of 25Mbps actually means a minimum of 12Mbps. Brilliant; well I suppose it is post-"1984".

We see things not as they are, but as we are .
- Anais Nin
Administrator MrSaffron
(staff) Thu 29-Mar-12 10:29:55
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Re: FTTC speed problem after modem replacement


[re: smurf46] [link to this post]
 
12Mbps is vastly better than the ADSL where even if down to 160Kbps they would simply say take it, or we can cease service attitude of wholesale

Andrew Ferguson, [email protected]
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User Orddu
(learned) Fri 30-Mar-12 11:57:57
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Re: FTTC speed problem after modem replacement


[re: Azzaka] [link to this post]
 
Well, I've had some updates that Zen and BT have commenced wrangling, so...

Let battle commence!
Standard User Orddu
(learned) Fri 30-Mar-12 16:23:47
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Re: FTTC speed problem after modem replacement


[re: Azzaka] [link to this post]
 
BT man just left after 2.5 hours.

He's changed the modem and PSU, which didn't help.

Running the BT Beta speed checker (as you can only run the other one once an hour) we've had results ranging from 6 to 39 meg down.

He's called his support people who of course can't see those results (as for some reason they're not logged - bah) but he's prepared to vouch for having seen them. The fluctuations have been mad.

He's hoping they'll sanction a "lift and shift" to get us onto new kit, but that's in their laps now. They don't like doing that since any kit they shift off of is apparently marked as "ill" and never used again.

He's satisfied there's something screwy going on though. Oh, and yay me, we were the first FTTC off our cab, since we're in port 701 which is the first one in it.

What'll happen next... who knows...
Standard User Orddu
(learned) Fri 06-Apr-12 10:36:17
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
Update for anyone who's still remotely interested...

Final analysis when 2nd BT engineer came this morning:

Manky copper

Lots of problems, error correction etc. on our connection. He's swapped the pair from that line with the other pair to our second line (which has bog-standard ADSL on it) and the problems his kit was recording have gone.

We're just waiting now for the line profile etc. to be reset and hopefully that'll sort us out.

On the plus side, BT now admit it's a fault and it's off our premises, so if it doesn't resolve now, shouldn't be hard to pass it back to them. Yay. And we've now got a new modem, new modem PSU, new VDSL faceplate (as it was the wrong one) and a spare router cos we bought one last week just in case...

And a big HOORAY for Leo at Zen, who took this on board and got things rolling. Thank you!
Standard User Orddu
(learned) Fri 06-Apr-12 13:20:59
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Re: FTTC speed problem after modem replacement


[re: Orddu] [link to this post]
 
BT test now showing 29.

Throughput is still 18.

I think they've half-fixed it, or something somewhere needs to be reset. Anyone know any magic words for that?
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