Question re: modem and router location (Infinity)

Hi all,

I got Infinity installed a month or so ago and am extremely happy with it. The only problem is that the engineer arrived when I was out and my wife was at home (doh!).

My master socket is in the hall, and the engineer informed me over the phone that it would be too difficult (or messy) to run the cable up to my study, so I'm now stuck with the modem, the HomeHub 3 and my NAS all in the hall (plus a SamKnows unit which I haven't connected yet, since I don't want it stuck in the hall as well!).

My question is, can I connect a Powerline networking plug to the modem in the hall, and connect the HomeHub to another in the study to get everything out of the hall except for the modem? Will this work, or does the HomeHub have to stay directly connected to the modem? Or is there any easier/cheaper way of doing this? (note: I don't want to start trying to drag a pile of CAT-5 up through my walls)

Thanks!

I am currently using HomePlug units at home with FTTC and it works fine. I would suggest getting the 500Mbps rated units, though as the 200 Mbps units probably won't hit 40Mbps throughput.

As Spasch says - yes.

However in your situation I'd be tempted to do what you suggest, compare the speeds taken before and after the move, then an hour or so later assuming those speeds are fine I would try taking the modem upstairs if it is a nuisance in the hall.

I would expect it to work, though can't be sure, and there would be a high chance it would be lower performance than the other two solutions. But without trying you won't find out.

I tried using a pair of 100Meg Homeplugs that I had but the throughput was around 10-12Meg on a connection of 38Meg.

If you are using a set, you will still need to have the Modem and Hub in the hall iirc and then the homeplugs connected via the Hub.

In reply to a post by Spasch:

I am currently using HomePlug units at home with FTTC and it works fine. I would suggest getting the 500Mbps rated units, though as the 200 Mbps units probably won't hit 40Mbps throughput.

I had a pair of Devolo 200Mbps AVs and they topped out at just under 30Mbps throughput. Do you use 500Mbps units? I now have an ethernet cable tucked down the edge of the carpet, much cheaper than the 500Mbps homeplugs .

In reply to a post by TheHorseman:

I had a pair of Devolo 200Mbps AVs and they topped out at just under 30Mbps throughput. Do you use 500Mbps units? I now have an ethernet cable tucked down the edge of the carpet, much cheaper than the 500Mbps homeplugs .

I currently use the Devolo 200Mbps units but my FTTC tops out at 28Mbps, so they work fine for me. No carpet downstairs, so ethernet is not an option and we have 4 of these scattered around the house (next to modem & router, next to NAS in the living room, in the bedroom and in the loft). The loft unit services the PCs that live there, the bedroom & living room units are used to stream movies & music off the NAS (using WD TV Live units)..

Cheers folks,

Much appreciated. I'll give all of the various configurations a try until I see which works best.

Is there no way you can get a cat5e or cat6 cable from modem to study? Tucked into the edges of carpets &c. It will be the easiest and cheapest way.

If the study is on the first floor, it should be on a different power ring - that could be a problem. And even on the same floor, rooms can have separate power rings.

I experimented with my modem to hub and used a long cable - no issues at all.

Unfortunately not. The hall floor is marble, and the master socket is on the opposite side of the hall from the stairs which have carpet. The only option that way is to track up the wall and go under the upstairs floorboards into the study. Not ideal. If the master socket were even on a stud wall it would help, but the walls of the hall are brick.

Is there skirting board in the hall? Can you get behind it? Or is there just a small corner bead at floor level? Get the cable to a corner and then vertically up at that point.

There is some very small quadrant trunking which could be useful.

If you go for two pair Cat5e it is smaller in diameter than 4 pair and will carry 100Mb which will be sufficient.

I'm considering Infinity too, and have a similar setup in my house. Master socket is in the hall downstairs next to the main door. And my 'office' is on the first floor where I want everything to be.

I read somewhere (either here or BT's own forum) that on the installation day, the BT engineer could make a slave socket into a master socket? Or can install an 'extension' of up to 30 metres?

Is this not an option? Wouldn't it be possible to get them to send someone out again to change your master socket? Guess it will be chargeable though.

No, they can't make a slave/extension socket into a master socket, since the cabling to extensions isn't of sufficient quality to carry the signal.

And, as I said, the engineer on the day said it would be too messy to install the Data Extension Kit with the strange layout, although I think this was partly due to the fact that he just couldn't be bothered.

since the cabling to extensions isn't of sufficient quality to carry the signal.

if you already have extension sockets, what route does the wiring for them take?

No, they can't make a slave/extension socket into a master socket, since the cabling to extensions isn't of sufficient quality to carry the signal.

Unless you mean in your specific case, your extension wiring, won't be up to quality, then you are incorrect. The HWS (Home Wiring Solution) ordered by by some CP's allows for just this to be done.

In my case, the extension wiring definitely wouldn't have been up scratch.

Good news though - bought a couple of Devolos, connected the modem to the one downstairs and the Home Hub to the upstairs one, and it worked like a dream, with no configuration whatsoever required. Absolutely negligible drop in speed as well.

Yes, there are undoubtedly neater and cheaper ways, but this was quick and avoided me having to use my non- existent DIY skills. Thanks everyone for the advice.

In reply to a post by DarrenNI:

Hi all,

I got Infinity installed a month or so ago and am extremely happy with it. The only problem is that the engineer arrived when I was out and my wife was at home (doh!).

My master socket is in the hall, and the engineer informed me over the phone that it would be too difficult (or messy) to run the cable up to my study, so I'm now stuck with the modem, the HomeHub 3 and my NAS all in the hall (plus a SamKnows unit which I haven't connected yet, since I don't want it stuck in the hall as well!).

My question is, can I connect a Powerline networking plug to the modem in the hall, and connect the HomeHub to another in the study to get everything out of the hall except for the modem? Will this work, or does the HomeHub have to stay directly connected to the modem? Or is there any easier/cheaper way of doing this? (note: I don't want to start trying to drag a pile of CAT-5 up through my walls)

Thanks!

Is this standard practice by BT when installing infinity?

It depends what type of cable is used really. The last time I had a lightning strike which caused a line fault, I got the BT engineer to move the location of my master socket for me, as I cabled it in CAT6 he was quite happy to do so.

Yep, in my experience Devolo are the 'kipper's titties' of powerline adaptors.

In reply to a post by Zarjaz:

Yep, in my experience Devolo are the 'kipper's titties' of powerline adaptors.

Earlier I suggested to the OP he might be able to conenct a Homeplug direct to the VDSL2 socket, then the modem upstairs where he has the hub.

Is that feasible, or nonsense? I was working on the premise that the output from the socket is ethernet.

connect a Homeplug direct to the VDSL2 socket, then the modem upstairs where he has the hub.

Pass, I'd have thought using them between the modem and the router if anything, is this not what the OP has tried ?

Seen many use them after the router, and my only advice there is, you get what you pay for, and always use them direct into the socket, not on an extension lead/adaptor.

im not sure if it will work between the vdsl faceplate and modem, can the powerline adaptors deal with a DC circuit?

What DC circuit?

I did say, (you may not have noticed), that my suggestion rests on the output from the VDSL2 socket being ethernet, ie PPPoE. So may be able to traverse the HomePlug setup in the same way as it would traverse the data extension kit.

If there is a DC output as well from the VDSL2 socket, what is that for?

Would you agree the worst case scenario is that it just doesn't work?

I'd be prepared to give it a try - the only problem is that the Homeplug takes an RJ45 and the master socket takes a standard BT phone jack if I'm not mistaken, so presumably I would need an adapter cable to do this?

The VDSL faceplate takes either RJ11 or RJ45, so you could try an RJ45 from the filter to the home plug. I reckon this won't work, or if it does, will cripple the sync rate.

I'll give it a go tonight and see if it works. Doesn't worry me if it doesn't, since I now have a big mess of cables in the study instead of the hall.

If the study is on the first floor, it should be on a different power ring - that could be a problem. And even on the same floor, rooms can have separate power rings.

Seem to come across this misconception quite a lot.

Home plugs will communicate when connected to any number of different circuits within the property. That's what they were designed to do. The consumer unit (fusebox) acts as the bridge. There are possible implications if there is more than one consumer unit in the property, but even then it only effects the speed. There are probably devices that prevent transmission, but they are unlikely to be found in a domestic or small business scenario.

Trawling google however, there seems to be a lot of misinformation on the web.

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So, explain why they will not work when connected on an extenszion lead?

Or, why they will not work if I connect one to the ring serving my comms room - server, router, switch, &c and the other to teh ring serving my office?

In reply to a post by MHC:

So, explain why they will not work when connected on an extenszion lead?

Maybe the extension lead has a built-in HF filter? That'll stop 'em.

Until I had a re-arrange recently I was using 3 Homeplugs- 2 downstairs, both plugged in to 4-way 2-metre extensions, the third upstairs on a different ring main. Worked fine.

Edited by billford (Thu 12-May-11 21:26:55)

As Bill says I think filters can be a problem. I have read about people blaming UPS's aswell.

That's why they state on the same consumer unit. Any type of metering/ups/filtering that is on the main supply can effect the signal. Say for example you have a small consumer unit for your comms room with a built in UPS or voltage smoothing device (becoming more and more common now) on the sub distribution cable to it. It will work anywhere in front of that device but won't pass through to get to another consumer unit. That's why I said it is usually ok in a domestic or small office environment, because mostly they have one consumer unit and they don't employ these other techniques.

I can't confirm which devices do or don't block signal, its just what I have read. But if you ring the manufacturer they will tell you what might be the cause. Bear in mind of course there are different specs and quality of homeplugs with different standards, that could have an impact as well. You have to match them all for them to talk to each other.

Edit: Forgot to mention if you have a three phase supply MHC, then consumer units are normally spread over the different phases to balance the load. That would be the most obvious reason for them not to be able to communicate?

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Edited by mrnelster (Fri 13-May-11 07:02:19)

Its a genuine question as I don't know the answer but isn't the face plate just putting out the VDSL modulated digital signal still with its carrier frequencies for the modem to strip out? I know that powerline adapters can carry various types of digital signals but I was not aware they could transmit high frequency analogue signals as well as don't the adapters use a similar modulation system wouldn't this interfere? The modulated signal will go down a Cat 6 cable of course just as they go down a telephone line.

It doesn't happen often but in this case, I'm afraid RobertoS is talking nonsense, the VDSL socket is certainly not an ethernet interface, however the BT modem output is and this can be connected to the router via Homeplugs as the OP has done successfully.

It doesn't happen often but in this case, I'm afraid RobertoS is talking nonsense

You could of course have signed in, and then stated he was mistaken.

.

In reply to a post by mrnelster:

It doesn't happen often but in this case, I'm afraid RobertoS is talking nonsense

You could of course have signed in, and then stated he was mistaken.

.

But that would mean he does not need to PM everyone trying to find out who posted ...

Earlier I suggested to the OP he might be able to connect a Homeplug direct to the VDSL2 socket, then the modem upstairs where he has the hub.

Is that feasible, or nonsense? I was working on the premise that the output from the socket is Ethernet.

You must not have had your Weetabix that morning!

Homeplug between modem & router should be fine (badwidth apart), definitely not between faceplate & modem (that link just carries the VDSL signal, not ethernet frames).

Edited by mr_bean (Fri 13-May-11 14:01:34)

But the VDSL signal contains Ethernet frames.

Does anyone here know powerline adapters work anyway? Are they anything to do with ethernet other than that their sockets are designed to take RJ-45 plugs?

I'd still like to see what happens if it is tried.

(Edit - a little bit of googling seems to show that powerline technologyprotocol is nothing to do with ethernet, just transmission of the received signal. In which case there is a distinct possibility it would work).

Edited by RobertoS (Sat 14-May-11 16:07:37)

In reply to a post by Anonymous:

It doesn't happen often but in this case, I'm afraid RobertoS is talking nonsense ....

Moi?

In reply to a post by RobertoS:

But the VDSL signal contains Ethernet frames.

Not really.

It contains a series of "tones" over a range of frequencies that, when amplified, decoded and rearranged (particularly if interleave is on) can be assembled into Ethernet frames... not at all the same thing!

(Edit - a little bit of googling seems to show that powerline technologyprotocol is nothing to do with ethernet, just transmission of the received signal. In which case there is a distinct possibility it would work).

Virtually no possibility at all... it's possible the signals sent down the mains are akin to VDSL or ADSL tones, but the point of the adapter is to convert Ethernet to and from those signals. Just as the VDSL modem does for the phone line, but those signals are nothing like Ethernet...

In reply to a post by billford:

In reply to a post by RobertoS:

But the VDSL signal contains Ethernet frames.

Not really.

It contains a series of "tones" over a range of frequencies that, when amplified, decoded and rearranged (particularly if interleave is on) can be assembled into Ethernet frames... not at all the same thing!

I believe you Bill, but can you give me a source for that, as I spent an age seaching before posting that and found nothing really useful.

(Edit - a little bit of googling seems to show that powerline technologyprotocol is nothing to do with ethernet, just transmission of the received signal. In which case there is a distinct possibility it would work).

Virtually no possibility at all... it's possible the signals sent down the mains are akin to VDSL or ADSL tones, but the point of the adapter is to convert Ethernet to and from those signals. Just as the VDSL modem does for the phone line, but those signals are nothing like Ethernet...

Similarly, the nearest I got to how powerline adapters work was "orthogonal multiplexing", but no mention of the incoming signal needing to be ethernet. So anywhere I can read up for more detail please?

In reply to a post by RobertoS:

I believe you Bill, but can you give me a source for that, as I spent an age seaching before posting that and found nothing really useful.
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Similarly, the nearest I got to how powerline adapters work was "orthogonal multiplexing", but no mention of the incoming signal needing to be ethernet. So anywhere I can read up for more detail please?

You really need someone with a better understanding than I have of what goes on at the bottom levels of the OSI model, but here's my take on it.

First, I put the word "tones" in quotes to indicate that it's an analog frequency based system (though a bit more advanced than the acoustic couplers of days gone by!). More here, though it probably won't tell you anything you don't already know.

Second, the word "Ethernet" has more than one meaning:

It defines a number of wiring and signaling standards for the Physical Layer of the standard networking model as well as a common addressing format and a variety of Medium Access Control procedures at the lower part of the Data Link Layer.

My bold.

So at the data level, the outputs from NICs, routers, Ethernet homeplugs (into the mains) and broadband modems (into the phone line) follow Ethernet standards and protocols, so in that sense you were right- they all carry Ethernet data. But at the physical layer of the OSI model that's almost irrelevant- it's how that data is carried that matters, and the signal levels present at a network RJ45 connector are nothing like those that are suitable for putting down a phone line!

(Homeplugs and BB modems both use Orthogonal frequency-division multiplexing by the way, but that's more of a mathematical technique for handling the data than having anything to do with the data itself)

But there are also several physical manifestations of Ethernet- thick (co-ax), thin (co-ax), fibre-optic (one fibre for each direction), the twisted pair (one pair for each direction) that we all know and love and probably others I've forgotten about. These all use different voltage levels etc and so (even ignoring the different connectors) you can't just connect one to another and expect it to work. Similarly for a phone jack and a homeplug.

Homeplugs and broadband modems both do similar things- they convert the digital networking signals into a form that is more suitable for transmission down the chosen physical link (and convert the signals coming the other way of course). But because they serve different requirements, they have different electrical characteristics and so aren't compatible either with each other or the "original" signal they are carrying.

I'll be honest- I'm not all that happy with the above, it rambles a bit . But I'm just an electrical engineer not a networking expert, and I hope it makes some things a bit clearer.

Edited by billford (Sun 15-May-11 12:41:10)

I have not read the whole thread so forgive me if I have the wrong end of the stick. Do you propose to use mains adaptors to connect the VDSL modem to the faceplate fliter?
Apart from this probably being against BT T&C, (all modems and router/modems have seperate power supplies to reduce the chance of mains finding it's way into the phone network) the VDSL signal may well get lost in the general mush produced by them.

all modems and router/modems have seperate power supplies to reduce the chance of mains finding it's way into the phone network

Que ? Separate power supplies, separate from what ? Each other ? The telly ? Next door ? If the power supply for a modem/router etc goes wrong, then the fact that it is usually connected direct to the telephone line via the RJ11 lead would mean it has a very easy way on to the Openreach pair.

Homeplugs and broadband modems both do similar things- they convert the digital networking signals into a form that is more suitable for transmission down the chosen physical link (and convert the signals coming the other way of course). But because they serve different requirements, they have different electrical characteristics and so aren't compatible either with each other or the "original" signal they are carrying.

There's a useful article covering some of the details of how they work here (courtesy of Wikipedia) which might help RobertoS understand why they need to be fed Ethernet frames.

They're actually pretty complex, encrypt the frames, do forward error correction and acknowledgement that the frame has been received as far as I can see.

Even if they worked as RobertoS thought, simply transferring signals from one plug to another without interpreting what the signal represented they probably wouldn't work for VDSL signals. If they behaved purely as a bit of wire they'd need to just connect the Ethernet transmit pin on one side to the receive pin on the other and vice versa using/emuating two pairs - that wouldn't work with VDSL which achieves a full duplex link on one pair by frequency division multiplexing the up&downstream signals and driving from both ends.

Rather more mundanely how would you connect the RJ11 from the faceplate to the RJ45 on the homeplug?If you took and RJ11<->RJ11 lead and plugged it into the central 6 pins of the RJ45 the VDSL signal (central pair) wouldn't actually connect to anything on a 100Mb/s Ethernet interface (that pair isn't used in 100Base-T).

I do confess though that one thing I haven't figured out is whether, when you use three or more of the things, what you get is more akin to an Ethernet hub or a switch - anybody know?

Edited by mr_bean (Sun 15-May-11 22:38:30)

In reply to a post by DarrenNI:

In my case, the extension wiring definitely wouldn't have been up scratch.

Good news though - bought a couple of Devolos, connected the modem to the one downstairs and the Home Hub to the upstairs one, and it worked like a dream, with no configuration whatsoever required. Absolutely negligible drop in speed as well.

Yes, there are undoubtedly neater and cheaper ways, but this was quick and avoided me having to use my non- existent DIY skills. Thanks everyone for the advice.

Which did you end up getting?
200mbps or 500mbps? or something else?

200mbps - fast enough for anything which I need, but probably not ideal if I were to be streaming HD video from the NAS or the like. Tempted to connect my Samknows unit to one end to see what the speed impact actually is.

In reply to a post by DarrenNI:

200mbps - fast enough for anything which I need, but probably not ideal if I were to be streaming HD video from the NAS or the like. Tempted to connect my Samknows unit to one end to see what the speed impact actually is.

I found that my 200Mbps Devolos topped out at just under 30Mbps throughput despite saying that they were connected at approx 100Mbps. They have now been replaced by a long ethernet cable.

In reply to a post by DarrenNI:

200mbps - fast enough for anything which I need, but probably not ideal if I were to be streaming HD video from the NAS or the like. Tempted to connect my Samknows unit to one end to see what the speed impact actually is.

That will be more than fast enough to stream high definition movies - I have a set of the Devolo 200Mbps units and stream 1080p with ease..

The 200Mbps is both directions combined, thus 100Meg either way in perfect conditions, and then as the metres of wiring increases throughput will drop further.

Ethernet cable is still best, but for those not able to run cable or put ends on CAT5e/6 then the homeplugs have represented a solution for some time.

Indeed. Best ones available are the Solwise Gigabit.

http://www.solwise.co.uk/net-powerline-gig-index.htm

The throughput achieved on homeplugs is always well under the headline speed but in a house wired in the last 25 years you should be able to pull 100+ Mbit realistic throughput on the Solwise 1GBit set.

Reading several reviews and benchmarks, this is the highest throughput seen to date.

Still slower than my 5GHz N though... Just.

In reply to a post by MrSaffron:

The 200Mbps is both directions combined, thus 100Meg either way in perfect conditions, and then as the metres of wiring increases throughput will drop further.

Yes the condition and length of the wiring matters, I cannot guarantee where the wiring goes in my house, when an electrician did some wiring in my kitchen he found that three pairs of sockets were spurred off the main ring

Ethernet cable is still best, but for those not able to run cable or put ends on CAT5e/6 then the homeplugs have represented a solution for some time.

I had been using the homeplugs because I was too lazy to do it properly, I decided to cable it in the end as it was cheaper than another set of homeplugs.