Kitz Forum

Broadband Related => ADSL Issues => Topic started by: zikit on December 03, 2018, 11:29:11 AM

Title: very odd behaviour of broadband connection
Post by: zikit on December 03, 2018, 11:29:11 AM
I have an unexplained very odd situation that maybe someone here might understand or be able to explain.
Broadband migrated from BT connection to another provider.
Standard ADSL2+ service.
Brand new TP-Link TD-W9970 router.
Entered normal parameter settings for connection - PPPoA/VCMUX/0/38.
Router connected but the connection displayed symptoms like there was no DNS.
Tried several alternative DNS settings to no avail.
Eventually tried the automatic connection detection wizard.
Here it gets bizarre.
Router does its detection as ADSL / LLC / PPPoE / 0/38 and makes a successful connection.
Everything springs to life and just works.
BUT it should be VCMUX / 0/38 / PPPoA, and shouldn't be working
Can anyone explain why or how we have a successful connection when we shouldn't ?
Title: Re: very odd behaviour of broadband connection
Post by: tubaman on December 03, 2018, 02:39:31 PM
Which ISP are you using, as they do not all use the same connection protocols?
As an example I found this (which is likely not current, but gives an idea) - http://www.bestrouter.co.uk/articles/uk-isp-adsl-settings (http://www.bestrouter.co.uk/articles/uk-isp-adsl-settings)
 :)
Title: Re: very odd behaviour of broadband connection
Post by: burakkucat on December 03, 2018, 05:14:39 PM
Welcome to the Kitz forum.  :)

One other question: What is the serving telephony exchange, to which your line is connected?
Title: Re: very odd behaviour of broadband connection
Post by: j0hn on December 03, 2018, 05:37:56 PM
Would entirely depend on the new ISP, and the serving exchange.

Without those details a working solution would be harder to offer.
Title: Re: very odd behaviour of broadband connection
Post by: zikit on December 04, 2018, 10:05:24 AM
Hi.
Thanks for answering.
Exchange is Nailsworth SSNAH, whose parent exchange is Stroud SSSTD.
All settings checked with ISP - VPI=0 / VCI=38 / Protocol=PPPoA / Multiplexing=VC based / Authentication=CHAP / MTU=1500
Title: Re: very odd behaviour of broadband connection
Post by: j0hn on December 04, 2018, 12:16:39 PM
Would entirely depend on the new ISP, and the serving exchange.

Without those details a working solution would be harder to offer.

We need to know the ISP.
Title: Re: very odd behaviour of broadband connection
Post by: Chrysalis on December 04, 2018, 02:01:18 PM
I dont understand why some people on the net dont want to reveal their isp, dont worry we wont bite, the reason we need to know is that different isp's may sometimes have different connection parameters.
Title: Re: very odd behaviour of broadband connection
Post by: burakkucat on December 04, 2018, 05:39:31 PM
Exchange is Nailsworth SSNAH, . . .

Thank you.  :)

So not a "20CN only" equipped exchange. That's one item off the list. Puzzling . . .
Title: Re: very odd behaviour of broadband connection
Post by: j0hn on December 04, 2018, 07:11:08 PM
I dont understand why some people on the net dont want to reveal their isp, dont worry we wont bite, the reason we need to know is that different isp's may sometimes have different connection parameters.

and some ISP's will use 1 operators equipment in some exchanges and use other operators equipment in other exchanges.

unless someone is the ISP's only customer I can't see any reason not to disclose this. Especially when it's specifically requested and noted to be essential information.

Is there a way to identify the far end DSLAM with a TP-Link TD-W9970?
Title: Re: very odd behaviour of broadband connection
Post by: dee.jay on December 06, 2018, 01:41:53 PM
If you can see the IP address of the poster, could just do a whois lookup on it and see who owns the block of IP space it's in...

(Assumes of course the person is posting from their home broadband and not a mobile/cell phone etc)
Title: Re: very odd behaviour of broadband connection
Post by: roseway on December 06, 2018, 04:10:29 PM
We can do that, but it would be a breach of data protection rules to disclose it.
Title: Re: very odd behaviour of broadband connection
Post by: Weaver on December 11, 2018, 11:30:27 AM
Welcome to the forum!

I once had this exact problem. ADSL single-box routers that try and guess whether or not to use PPPoA (right answer) or PPPoEoA (wrong answer).

The right answer if you are using a BT-based service provider, unless you have no choice for some reason, is always PPPoA VC-MUX (MTU 1500) and the DNS Settings will be given to you automatically. Or you can set the DNS settings up by hand, to 8.8.8.8 / 8.8.4.4 or ask your ISP.

Your ISP may be using their own kit rather than BTís machines that go ping in the exchange though, a so-called LLU ISP. If so the above does not necessarily apply and different protocols and setting may be in use.

Thatís why we have to know which ISP you are using. I realise it may possibly be an embarrassing choice, but we will in that case be kind.  ;)

My problem was I think something to do with a fault in the ISPís (Demonís) equipment or BTís kit and was temporary. After a short while detection went back to normal.

When you say DNS symptoms, I take it that you canít browse the web but you can ping numeric IP addresses and you can fix things by setting the DNS server values up by hand either in your router or in your own machine?

If you do get DNS problems you may well be better using 8.8.8.8 (Google) or OpenDnsís very fast servers, or 1.1.1.1. These are all fast and extremely reliable as there are a lot of them distributed all over the place intelligently, many hiding behind Ďtwoí addresses in fact. And since some ISPsí servers are crap you could be better off using these than the ISPís own, never mind problems with auto identification of their addresses. An ISPís DNS servers that are of good quality will always have the advantage of proximity.