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FTTC plus homeplugs = 1/2 speed?

gyre
Grafter
Posts: 271
Registered: 19-11-2007

FTTC plus homeplugs = 1/2 speed?

Folks, I've tried to debug this problem until I'm well and truly blue in the face.  I really need your help Smiley
I'm on Plusnet Unlimited Fibre 80/20.  My Plusnet profile says I can get over 70mbit/sec.
I plug my supplied BT Openreach VDSL modem into my Draytek 2920 router.  I can connect via PPPoE fine.  Smiley
If I plug in a laptop via ethernet into one of the LAN ports on the 2920 and do a speedtest, I get 71mbit/s plus.  Fine.  Smiley
However, if I then plug in a homeplug via the same LAN port downstairs, and move the same laptop upstairs and plug it in to another homeplug, I get only 31mbit/sec.  Consistently.
I've tried a pair of devolo 200avs.  I expected those to be somewhat limited.  I then tried a pair of solwise 500avs.
So clearly the homeplugs are somehow limiting my bandwidth, right?
Well, yes, but I don't know why.  Using the 500av homeplugs I'm able to get a sustained rate copying files from PCs downstairs to PC upstairs of over 10MB/sec in both directions.
Why would the homeplugs allow 80+mbit/sec on file copies, but only 31mbit/s on Internet access?  MTU problems?  (I'm using 1492 on my PPPoE connection)
Completely stumped here and open to any advice.
Thanks!
-- gyre --
23 REPLIES
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: 26-11-2011

Re: FTTC plus homeplugs = 1/2 speed?

Hi gyre,
I can't believe I've come across this thread. I moved this weekend just gone and get pretty much full 80/20 but get around 30Mb on 200 Home Plugs. I've just ordered a pair of TP Link 500's to see if this improves throughput.
Ethernet Cable straight into the router gives 74Mb - I can only think that's an issue with the quality of the Home Plugs or something plugged in next to the Home Plugs that's causing interference. What speeds do you get through the 500's?
Chris Pettitt
Cloud Environments Engineer
Community Veteran
Posts: 38,460
Thanks: 1,030
Fixes: 62
Registered: 15-06-2007

Re: FTTC plus homeplugs = 1/2 speed?

A suggestion
Try the homeplugs on the same fused circuit
It shouldn't make any difference BUT it is worth a check
Community Veteran
Posts: 1,616
Thanks: 22
Registered: 29-06-2010

Re: FTTC plus homeplugs = 1/2 speed?

I have a pair of TP-Link 200 Home Plugs, and get about half my download speed on that connection. A points to consider:
Are either of the Home Plugs plugged in to an extension socket strip?
This is touted as a mighty no-no, but although the received wisdom is that you'll be very lucky if they work at all set up like that, especially if you have a surge protector, I have both of mine plugged in to that type of socket - they obviously work, but I reckon that's probably the cause of the slower speed.
Superuser
Superuser
Posts: 3,274
Thanks: 1,707
Fixes: 11
Registered: 10-04-2007

Re: FTTC plus homeplugs = 1/2 speed?

It may be worth reading this page
Solwise is a significant supplier of this type of equipment and in this article tries to be realistic about the performance you should expect.
N.B.  It may be worth looking at their Twisted Pair product?  I've not tried this yet - but it is a contender for an extension to "The Shed".
HTH
Maurice
Community Veteran
Posts: 3,382
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Registered: 18-01-2013

Re: FTTC plus homeplugs = 1/2 speed?

Something else to try is to remove *all* devices from all the plug sockets in the house then use only the modem/router/homeplugs and see what happens.
There could be RF filter devices in just about anything you plug into your mains which could interfere with the operation of the homeplugs.
If your speed increases significantly, then plug things in one by one and see what happens.
gyre
Grafter
Posts: 271
Registered: 19-11-2007

Re: FTTC plus homeplugs = 1/2 speed?

Thanks folks.  All good and sensible advice.
The 2 solwise 500av homeplugs are on the same fused circuit.
I get over 80mbit/sec when transferring files between the plugs.  That's a sustained 10-11MB/second either direction copying files.
There are no other homeplugs anywhere else in the house.  Just the one downstairs and the one upstairs.
They each have their own socket.  No trailing leads etc.
As they both have filtered mains passthroughs (piggys), I'll try plugging the router and modem directly into them and see if that helps.  Will report back if it does.
Thanks!
gyre
Grafter
Posts: 271
Registered: 19-11-2007

Re: FTTC plus homeplugs = 1/2 speed?

OK, after looking at wireshark output I think I've found the problem.
I was setting a MTU on the draytek 2920 of 1492.  Changing it to 1442 gave me back the missing bandwidth.
Sigh.
-- gyre --
gyre
Grafter
Posts: 271
Registered: 19-11-2007

Re: FTTC plus homeplugs = 1/2 speed?

Well, sort of.  Sometimes I get 60-ish mbit/sec, and sometimes 40.  Still better than what I was getting before the MTU change, but not perfect.  Suprised changing MTU from 1492 to 1442 made any difference at all, but changing MTU values on the router makes a huge difference.
anniesboy
Grafter
Posts: 385
Thanks: 2
Registered: 06-01-2011

Re: FTTC plus homeplugs = 1/2 speed?

Chris.
Following your saying you were buying 500 Homeplugs, Im wondering how they perform ?
I use 200 Homeplugs at the moment but FTTC is hopefully coming soon to my cabinet hence my interest.
beeceegee
Aspiring Pro
Posts: 534
Thanks: 37
Fixes: 3
Registered: 27-11-2012

Re: FTTC plus homeplugs = 1/2 speed?

A lot depends on the quality of your household wiring, but the Solwise article referred to above explains very well why you should not be too optimistic regarding the throughput using homeplugs. I had a set of Devolo 500AVs and was disappointed with the results (for the price). I swapped them for a much cheaper set of Solwise 200AVs; frankly the 25-30Mbps throughput I get using the 200s is hardly any worse than the 500s. As the plugs are only used for streaming the TV and related kit it's plenty

gyre
Grafter
Posts: 271
Registered: 19-11-2007

Re: FTTC plus homeplugs = 1/2 speed?

I've been using devolo 200s for a few years.  100% rock solid.  A few months back I got a few devolo 500s.  After a week I sent them back.  They would drop packets and then go off-line for minutes on end.  They were just awful.
The solwise 500s I'm using are very solid.  In terms of reliability I'm happy with them so far.  In terms of speed, I'm not seeing a lot of difference between them and the old 200s as far as my broadband is concerned.  Mind you, the supplied app says I'm connecting between 170 and 210 mbit/s.  I'll have to try to optimise that by using the filtered pass-thru ability of the solwise piggies when I next reboot my home network and see if that helps.
-- gyre --
Community Veteran
Posts: 1,293
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Registered: 22-06-2012

Re: FTTC plus homeplugs = 1/2 speed?

I'm running a pair of 500s & getting 45 down & 13 up, almost  exactly the same as when wired.
deathtrap
Grafter
Posts: 1,063
Thanks: 4
Registered: 23-04-2013

Re: FTTC plus homeplugs = 1/2 speed?

Homeplugs and xDSL don't mix well, but hardly surprising really, the amount of EMI or RFI they must generate, that will most likely be the cause of the lack of performance on the internet connection, If they are having an adverse impact on the VDSL2 signal @ your modem ( causing high error rates) then don't be surprised when DLM strikes and lowers your speed and increases latency,
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: 26-11-2011

Re: FTTC plus homeplugs = 1/2 speed?

The fact that Homeplugs and VDSL use the same frequency doesn't help either :/
Chris Pettitt
Cloud Environments Engineer