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Unstable connection with third party routers

netman82
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Registered: 14-09-2013

Unstable connection with third party routers

I have a PlusNet supplied Thomson 585v7 router. My connection is stable with this box; it syncs at approx. 9Mb. I am on the Value package.
I would like to change the Thomson for a 3rd party device for a number of reasons such as ability to change LAN subnet, faster wireless and higher sync rates.
I have tried 3 new routers from TP-Link, Zyxel and D-Link. All 3 sync at least 11Mb, but not one can hold a steady connection. Here is what happens:-
* Router connects, sync and internet lights solid green
* Pings to various sites succeed for a 4-5 seconds then drop for a few seconds, this repeats in a loop for up to a few minutes
* Websites are very slow to load or do not load at all
* Then the sync and internet lights drop (after a few minutes of above) and the connection is lost
* The above repeats indefinitely
This is what I’ve done so far:-
* Plugged into the master socket with nothing else attached
* Tried 2 other known good filters
* Tried a different modem cable
* Connected to router via LAN cable (not wireless)
* Reset the 3 routers mentioned above to factory defaults before configuring as recommend in the PlusNet support pages
* Tried ADSL2 instead of ADSL2+ modulation to peg back sync rate to 9Mb
* Tried the 3 routers on another PlusNet connection just down the road, all work perfectly!
PlusNet support had interleaving enabled on the line, but this has only served to increase ping times and has done nothing to improve connection stability on any 3 of the third party devices.
PlusNet support state that an engineer’s visit is not required and that I’m to blame for mis-configuring all 3 of the alternative routers. This I take umbrage to as I’m not a typical home user, I am an experienced IT support engineer and I am quite capable of following their basic instructions.
So my only option is to stay with the 585v7 or leave PlusNet, neither of which I want to do. I have been a loyal customer for many years and have recommended PlusNet on numerous occasions, but I feel let down and frustrated with their support.
Any help would be much appreciated.
23 REPLIES
Community Veteran
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Registered: 10-06-2010

Re: Unstable connection with third party routers

Can you give us the exact model numbers (and hardware version numbers) of the 3rd party routers? There are a lot of different TP-Link and D-Link routers, so just the manufacturer doesn't narrow it down very much.
nanotm
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Re: Unstable connection with third party routers

a 3rd option would be to disable dhcp +wifi on the Thompson router and use it purely as a modem, and use one of the 3rd party routers to provide your internal networking setup and control.
there's a fair to middling chance the reason for the instability is down to the chipset within those 3rd party routers not being fully compatible with the DSLAM (hence the stability issues) which as you have rightly suggested wont be made any better by changing there configuration
the only way to eliminate the chipset incompatibility would be to find out what your DSLAM is running (samknows normally has this sort of info on there website) and then find a compatible router so you can embark upon a single box solution.
as far as it goes the Thompson isn't that great if you need any form of advanced setup or connection for many devices, but as a cheapo plug n play for minimal devices for the average home user its fab.
just because your paranoid doesn't mean they aren't out to get you
netman82
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Registered: 14-09-2013

Re: Unstable connection with third party routers

@nanot
Many thanks for your reply.
Can you help me in finding the information I require? What exactly am I looking for and how do I find it re: DSLAM to ensure I get a compatible router? I've had a look at SamKnows but don't know where to start.
Thank you for your 3rd option suggestion too.
Community Veteran
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Re: Unstable connection with third party routers

I don't think many people care about chipset compatibility or matching chipsets with the exchange these days.
You can find the vendor of the equipment in the exchange from the adsl line stats from your router. BT-based ADSL2+ connections always seem to be TSTC or IFTN - Texas Instruments or Infineon. Texas Instruments spun off or sold off their ADSL chipset division to Infineon and later it became Lantiq. Routers based on Lantiq chipsets aren't common, although some types of BTHub3 and BTHub4 use them.
You also haven't told use the model numbers of the routers you already tried so we won't know what chipsets they contained, the 585v7 uses a Broadcom chipset, which are fairly common, if I had to guess then it's quite likely the D-Link and TP-Link you tried also used Broadcom chipsets.
nanotm
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Re: Unstable connection with third party routers

true but there's a reason for it, most modern routers have one of the Broadcom or Infineon chipsets that are fully INS compliant
possibly cut down versions of the Broadcom chipset or older variants (a common problem with cheaper home use kit) so they wont support impulse noise suppression which the expensive routers tend to support,
most BT owned DSLAMS are Hawaii based Infineon units on the 21cn system, its been a while since I last tried to lookup the whole dslam/msan/router compatibility stuff, when I was having such strange problems I bit the bullet and bought a billion 7800 which is as a happy coincidence a fully fttc capable router but also eliminated the problems I was having after having tried out 4 different home hub variants through my old isp.....
sometimes the problem is caused by a combination of hardware mismatch and sub optimal line, if you can eliminate one problem (clearly you can eliminate the hardware problem by using the Thompson) then it shows there's an underlying problem, the underlying problem isn't bad enough to trigger a fault scenario (your getting a decent speed for adsl) because even though there are problems with line standard there not enough to hamper stability when using ISP supplied equipment.
another thing to consider is the age of the routers your trying to use, wifi modules are frequently designed to fail simpy because the glue used in there manufacture degrades into an acid with moisture in the air causing problematic operation (this normally takes about 2 years in temperate indoor operation) but in high humidity areas may occur faster.
just because your paranoid doesn't mean they aren't out to get you
Community Veteran
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Registered: 10-06-2010

Re: Unstable connection with third party routers

Without seeing some line stats we also don't know if 11Mb is just an over ambitious speed for the line.
netman82
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Registered: 14-09-2013

Re: Unstable connection with third party routers

Thank you both for your contributions so far I really do appreciate it.
Here are the 3 routers I have tried; granted they are old low-end devices but I cannot afford new or high-end devices:-
D-Link DSL-2740R A1
Zyxel P-660HW-T1 v3
TP-Link TD-W8901G v3
According to SamKnows my exchange is as follows:-
http://www.samknows.com/broadband/exchange/SLSW
Working on getting the other info.
netman82
Dabbler
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Registered: 14-09-2013

Re: Unstable connection with third party routers

Attached are the ADSL line stats from my Thomson router.
UPDATE: not sure if it's relevant, but 32 minutes online the FEC error stat has risen to: 1,123,667! This seems like a huge number.
Community Veteran
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Re: Unstable connection with third party routers

According to:
http://wikidevi.com/wiki/D-Link_DSL-2740R
http://wikidevi.com/wiki/TP-LINK_TD-W8901G_v3.x
http://www.skyuser.co.uk/forum/technical-discussion/44158-zyxel-p-660hw-t1.html
(wikidevi.com didn't have an entry for the P-660HW-T1 v3, but it has the v1 and v2 which are TrendChip based)
It looks like all 3 third-party routers you tried were based on TrendChip chips, which explains why they all connected at an unstable and unsustainable high speed. I've seen it reported elsewhere that TrendChip based hardware tends to go for a high sync speed, which can result in an unstable connection that frequently drops.
PeeGee
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Re: Unstable connection with third party routers

Trend chipset modems don't seem to like long lines, though I have a 585v7 (broadcom) and a td-8816 (trend). The 8816 tends to sync slightly lower, but currently has been running 41 days and 20 hours since the last resync, at 3474Kbps/3dB/62.9dB, and that change was forced by me adjusting cables  Shocked
With different chipsets, the DLM recognises a swap and syncs at the highest suitable level at the time Wink
Plusnet Fibre (Sep 2014), Essentials (Feb 2013); ADSL (Apr 2009); Customer since Jan 2004 (on 28kb dial-up)
Using a TP-Link TD-W9980 modem-router.
Community Veteran
Posts: 4,970
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Registered: 10-06-2010

Re: Unstable connection with third party routers

I don't think the DLM knows nor cares if you've changed routers/chipsets (unless you connect and disconnect things too many times in a short space of time, of course). You always sync at the highest speed attainable at the time, subject to the parameters set by the DLM (noise margin, interleaving, banded speed), the parameters will be the same after switching to a different router. Different routers will end up achieving different speeds, some can be configured to be more conservative and end up with a lower but more sustainable speed.
netman82
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Re: Unstable connection with third party routers

So, it looks like I should aim to get an Infineon based device or perhaps a Broadcom, does anyone have any suggestions? I can't afford to buy new so will have to try and get an eBay bargain.
nanotm
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Re: Unstable connection with third party routers

just go with the option I outlined earlier,
if it makes you feel better to get something that isn't looseing one of the 4ethernet ports on the router then look for something that comes with an E-Wan port, if you want a quality all in one router  then something like a billion 7800n (if you insist on having built-in wifi)

http://www.ebay.co.uk/itm/Billion-BiPAC-7800N-300-Mbps-4-Port-Gigabit-Wireless-N-Router-/26128318730... that's probably the cheapest you'll find one for but look around there might be the odd deal somewhere, just beware they can develop faults once there over a year old, and these plenty of cheap imitations out there but the proper ones have a Broadcom chip inside (which works well with Infineon dslams) and there designed for use in a small to medium sized business environment complete with easy to use GUI interface for most advanced setup requirements, even better there capable of handling 96meg down 40 up connections (in case you get fibre in the future)
personally I like the time based IP filtering or lockouts which can be adjusted and saved on the fly without needing a restart Smiley which provides exceptional enforcement of boundaries for kids without needing to physically pull any plugs
just because your paranoid doesn't mean they aren't out to get you
netman82
Dabbler
Posts: 19
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Registered: 14-09-2013

Re: Unstable connection with third party routers

Thank you nanotm and also to ejs and PeeGee for their earlier posts.
Unfortunately nanotm I cannot afford much more than £20, but I appreciate your eBay link. I think I might end up going for a Broadcom based Netgear.