Kitz Forum
Broadband Related => ADSL Issues => Topic started by: noddy on March 04, 2017, 10:16:18 AM
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Hi while I wait for the exchange to be upgraded :fingers: which may or may not improve things ( when it's windy :) ) I started looking at MTU settings and after a few ping test it was showing 1430 as the highest with no packet loss ( almost sounds as if I know what I'm talking about - I don't really ;) ) so that leads me to think my MTU should be set at 1458 ? now should I set the router to this as well as the computers ? or does it not make a deal off difference ? cheers
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What is the current setting on your router?
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1492
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How were you testing it? What were you pinging? Some servers might have lower MTU values than what your connection can generally support.
1458 was an old default value in some Netgear routers. With a PPPoA connection, 1500 is a reasonable choice, I think 1478 gives a very small throughput increase due to optimizing ATM cell packing.
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I was pinging plusnet.net thinking my provider was a good a choice as any , using cmd , could be anything to do with our exchange being 20cn ?
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I've just spent a few minutes pinging plusnet.net before eventually realising that it should of course be plus.net.
I wouldn't have thought it's a 20cn issue, an MTU of 1500 isn't a new thing.
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1500 when possible. 1492 if you're stuck with hardware which doesn't support RFC 4638.
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I've just spent a few minutes pinging plusnet.net before eventually realising that it should of course be plus.net.
I wouldn't have thought it's a 20cn issue, an MTU of 1500 isn't a new thing.
sorry for that :-[
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On 20cn I'm using 1500 on a combined modem/router.
Sent from my Nexus 7 using Tapatalk
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ejs is exactly correct. All depends on what protocols you are using ADSL, VDSL, FTTC? PPPoA or PPPoE. Single-box modem-router combined or separate modem and router.
Tuning will only give you at most 3% more speed, or 0% depending on your setup. Let us know _all the details about kit, setting, services, protocols, line type_ and we will be able to advise.
Here is the rule in a nutshell:
About what works / doesn't work: If you have a separate modem, 1492 is the safe choice. Otherwise always use 1500 for maximum compatibility with the world at large. Beyond that all else is tuning/tweaking and we would have to advise you on that with a knowledge of all your details.
Earlier posters’ tips are valid or not dependent on your setup.
Tuning/tweaking: the possible gains from tweaking are not large (3% or 0% max) and we don't know how to do it without your details. ejs' excellent advice is protocol-specific, as he says, and 1478 is an optimum for efficiency with PPPoA _only_. But we don't know if you are using PPPoA or not.
(Further reading: The wikipedia article on PPPoE has a section on PPPoEoA over ADSL written by your truly, which goes through all the arithmetic in gruesome boring detail. It might be worth a read even if you are not using PPPoE. see other MTU thread)
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There is a website that will test the combination of your own kit, ISP and internet connection and check out your MRU so that you can see whether your chosen setting are actually working for incoming stuff. I've used it several times but I foolishly didn't save the url, so I would have to google it again, but it wasn't that hard to find.
I used it to test that my three separate DLink DSL-320B-Z1 modems are actually working properly with 1500-byte IP packets inbound (using separate router, ADSL2, BTW 21CN, with PPPoE on the link from router to the modems and PPPoEoA over DSL on the copper line). In my case, luckily (i) modems, and (ii) router, and (iii) the particular link from my modem to the BRAS in BT Land can all handle 1500+8=1508-byte long PPP PDUs.
You can of course try sending outbound packets of different lengths, but you need help from such a test server to test inbound stuff.
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well thanks for all the use full advise , as I thought I have a lot to learn :-[ I'll get back with more info , so thanks yet again
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Noddy, it's like Russian Dolls - there are all these layers upon layers of comms protocols and packets within packets within packets, each with some wrapping surrounding the payload within, then an outer wrapping that encloses that one and so on. Each one adding more overhead, and contributing more inefficiency. So there are all these terms for protocols and different standards' documents that contain pictures, and we have to say what layer off wrapping it is that we're talking about when we mention the length of something or talk about length limits, "it's the length of exactly what?" - including/excluding which wrappers. That's the reason for all the jargon that gets dragged in. There are concise pictures of all these levels of wrapping, I would have to dig for a min.
[Moderator edited to correct a typo.]
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I'm beginning to see what you mean , and thanks for your patience .
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On PPPoA, as you are, you should be able to use 1500. That's what I used when I was with Plusnet, and what I use now with A&A. All on 20CN.
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cheers I'll set them back see what happens :)
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Right, you are using G.dmt, PPPoA. Use MTU 1500. (1478 for PPPoA is a very slight performance tweak, slightly more ATM-efficient, as has already been said, I would have to do the arithmetic properly to work out exactly how much. But if I were you, I would not go that way, stick to 1500 as that way you won't have any problems, compatibility over minuscule speed increases.)
Can you confirm you are on a 20CN exchange, not 21CN? Would be worth ticking the ADSL2 tick box _in addition to_ G.DMT which you have ticked already, just in case ADSL2 works. It won't be available if you are still on a 20CN exchange.
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hi Weaver , yes exchange still 20cn but according to some locals will get fibre in April so I did wonder if that would mean an upgrade to 21cn ( I'll not be placing any bets on it happening ;) ) thanks for the help
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If your area is getting FTTC (which is still copper, not fibre, to your house as you probably know) then they may well be upgrading the exchange to 21CN very soon, or even have already done so.
It would be worth checking, maybe another kitizens could help with that.
Just in case you have been upgraded, it would be worth enabling ADSL2 in your modem as well as G.DMT (ADSL1). In my case, using a BT Wholesale line (non-LLU), I asked my ISP to move me to ADSL2+ / 21CN immediately when I found out the exchange had been upgraded to 21CN, and the immediate upgrade cost me a whole £11. The exchange upgrade was way before anyone in the area got FTTC. (Exchange NSBFD.) Your ISP may migrate users to 21CN, it all depends on the ISP and when they get around to it. I realise I was assuming you are non-LLU there. I can't remember whether you confirmed this already. It's all up to your ISP anyway. But at least if you enable the possibility of ADSL2 you will immediately get a speed improvement the moment your line is upgraded, even before FTTC.
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If your area is getting FTTC (which is still copper, not fibre, to your house as you probably know) then they may well be upgrading the exchange to 21CN very soon, or even have already done so.
It would be worth checking, maybe another kitizens could help with that.
Just in case you have been upgraded, it would be worth enabling ADSL2 in your modem as well as G.DMT (ADSL1). In my case, using a BT Wholesale line (non-LLU), I asked my ISP to move me to ADSL2+ / 21CN immediately when I found out the exchange had been upgraded to 21CN, and the immediate upgrade cost me a whole £11. The exchange upgrade was way before anyone in the area got FTTC. (Exchange NSBFD.) Your ISP may migrate users to 21CN, it all depends on the ISP and when they get around to it. I realise I was assuming you are non-LLU there. I can't remember whether you confirmed this already. It's all up to your ISP anyway. But at least if you enable the possibility of ADSL2 you will immediately get a speed improvement the moment your line is upgraded, even before FTTC.
useful info Weaver our exchange NSBIR
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:) Broadford exchange used to have wonderful holidays in Elgol years ago :)
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I would need some help looking up your exchange as the usual databases like SamKnows are always way behind. Someone here will probably be able to help with this.
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I does not necessarily follow that the Birsay exchange has to be upgraded from 20CN to 21CN equipment for a G.993.2 (VDSL2) service to be offered. The fibre head-end exchange (for the cabinet based DSLAMs) could be many miles away, on the mainland UK . . . most likely.
Here is the link (https://www.telecom-tariffs.co.uk/codelook.htm?xid=192784&cabinets=10544) to the current details, regarding the status of the G.993.2 service roll-out for the Birsay exchange, according to Magenta Systems CodeLook pages.
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I does not necessarily follow that the Birsay exchange has to be upgraded from 20CN to 21CN equipment for a G.993.2 (VDSL2) service to be offered. The fibre head-end exchange (for the cabinet based DSLAMs) could be many miles away, on the mainland UK . . . most likely.
Here is the link (https://www.telecom-tariffs.co.uk/codelook.htm?xid=192784&cabinets=10544) to the current details, regarding the status of the G.993.2 service roll-out for the Birsay exchange, according to Magenta Systems CodeLook pages.
well :fingers: that at the very least the connection to the exchange will improve but some how I doubt it :( think I let my expectations get carried away , back to two cans and string :)
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Burakkucat is of course quite correct, I forgot about that. Mea culpa. Might be, might not be in luck. But anyway in a more densely populated place such as Orkney Mainland there's possibly good news coming when FTTC arrives anyway.
Whereas I on the other hand get left out for another five years presumably unless I smarm round someone important, or someone important comes to live in my village. Or win the lottery and cough up for 4.6 mi of FTTP if they would even sell it. ([off-topic]Wonder what they do about the exchange in such a case? Can't legitimately sell it unless there is the link capacity behind it. Perhaps they just ignore that and con you?)
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the superfast is up and running 5 miles from me in a near by village as well as kirkwall , stromness plus a few other area's suppose like yourself weaver we're out on the edge's :(
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I does not necessarily follow that the Birsay exchange has to be upgraded from 20CN to 21CN equipment for a G.993.2 (VDSL2) service to be offered. The fibre head-end exchange (for the cabinet based DSLAMs) could be many miles away, on the mainland UK . . . most likely.
Judging by what's happening round here the push seems to be solely for FTTC, it wouldn't surprise me if BT intend to get rid of exchange-based DSL altogether and serve everything from the cabinet. There's certainly no sign of them migrating any more exchanges from 20CN to 21CN, nor any interest in the subject if you try to find out.
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Judging by what's happening round here the push seems to be solely for FTTC, it wouldn't surprise me if BT intend to get rid of exchange-based DSL altogether and serve everything from the cabinet. There's certainly no sign of them migrating any more exchanges from 20CN to 21CN, nor any interest in the subject if you try to find out.
to be honest I don't need superfast since our boys left home ;) , what I would be happy with is it keeping the sync rate around 4200 which is what I get re-syncing on a calm day and holds it fine until the wind starts :( but I've gone through all this in a previous post (out of interest )
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There's certainly no sign of them migrating any more exchanges from 20CN to 21CN
All 20CN exchanges being upgraded by end 2018
http://www.ispreview.co.uk/index.php/2017/02/bt-update-uk-fttp-sogea-3db-21cn-wbc-broadband-plans.html (http://www.ispreview.co.uk/index.php/2017/02/bt-update-uk-fttp-sogea-3db-21cn-wbc-broadband-plans.html)
Ian
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All 20CN exchanges being upgraded by end 2018
http://www.ispreview.co.uk/index.php/2017/02/bt-update-uk-fttp-sogea-3db-21cn-wbc-broadband-plans.html (http://www.ispreview.co.uk/index.php/2017/02/bt-update-uk-fttp-sogea-3db-21cn-wbc-broadband-plans.html)
Ian
we can only hope ;)
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Surely it would be cheaper for BT to get on with it and get rid of the 20CN asap rather than having to support two systems any longer, especially seeing as there are presumably not that many left.
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presumably not that many left.
From the ISP review article only 1600 exchanges left. So say 100 weeks...16/week
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Been waiting 11 years for are local exchange to be upgraded to 21CN and is still 20CN though FTTC crept in via a head-end exchange giving us more BB speed than a 21CN could provide, just wondering what other benefits there is to being on a 21CN exchange ?
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Surely it would be cheaper for BT to get on with it and get rid of the 20CN asap rather than having to support two systems any longer, especially seeing as there are presumably not that many left.
I was thinking that they probably want to get rid of both 20CN and 21CN exchange based DSLAMs. The recent trials of long range FTTC and 16Meg FTTC seem to be aimed at delivering services comparable to ADSL2+ from the cabinet. Would be interested to know whether user counts on ADSL are reducing, and by how much.
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benefits there is to being on a 21CN exchange ?
Uncapped upload (20CN capped at 448 kbps)
much improved DLM
faster download (if close enough to the exchange)
able to sign up with Andrews and Arnold
Ian
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Would be interested to know whether user counts on ADSL are reducing, and by how much.
Lots of statistics are available from Ofcom, things like the Connected Nations Report or quarterly telecoms data tables (https://www.ofcom.org.uk/research-and-data/statistics/stats17).
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Thanks to kitzuser87430 for that list - I had forgotten.
Is it the case that AA will not take on anyone who is on 20CN now? We discussed the issue of AA and 20CN in a earlier thread a good while back. Kitizen aesmith was, maybe still is, an AA 20CN user.
Any AA users who are on the traditional ‘units-based’ tariff will get twice as many MB 'office hours' download allowance.
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Kitizen aesmith was, maybe still is, an AA 20CN user.
Still is. There's no plan for 21CNat our exchange, they're going to site a cabinet by the exchange so the village can get FTTC. Everything out of range will have to stay 20CN, it's all EO so no existing cabinets.
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Is it the case that AA will not take on anyone who is on 20CN now
Yep, I went through the order process and was offered nothing.
There's no plan for 21CNat our exchange
Same as mine ....just by the end of 2018 along with the other 1598 20CN exchanges
only 100 EO lines on our exchange, but going by codelook 3 cabinets are pencilled in by Nov this year
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BT should have been made to prioritise this some years back.
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Still is. There's no plan for 21CNat our exchange, they're going to site a cabinet by the exchange so the village can get FTTC. Everything out of range will have to stay 20CN, it's all EO so no existing cabinets.
sounds like we're in similar situation's :(
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BT should have been made to prioritise this some years back.
I tried chasing this up via the various bodies, however nobody is interested in anything except "high speed" or "super fast" depending on who you're speaking to. They're all fully focussed on increasing the number of people getting speeds of 30meg or greater, and have no interest in service improvements that don't hit that definition.