New router has ruined my Plusnet Fibre connection!

Ok, the title may be slightly overdramatic but if anyone can figure out what may have happened here I'd be very grateful. I recently purchased an ASUS DSL-AC56U for its QoS/Bandwidth limiting features. I set it up on Monday and at first there were no problems. The sync speed (37/10) was the same as it was with my Plusnet Hub One except 0.5Mb higher on the upstream. FastPath on both up & down & G.INP enabled.

Yesterday G.INP was switched off, interleaving turned on for the downstream and the connection dropped several times. Download sync speed reduced to 34.5Mb.

Today the connection was quite bad, it dropped several times, packet loss on the BQM and the download sync now reduced to 33.1Mb. Looking at the DSL stats the SNRm on the downstream was bouncing around between 1.8dB & 5dB. Also 10000s of CRC errors. No problems on the upstream which has remained stable and unchanged throughout.

I then plugged my PN Hub One back in which has synced up at 30.7/9.4, and rang Plusnet who are sending an engineer Friday because sync is below minimum guaranteed (34Mb). I am not sure whether to suspect the Asus router as faulty or a line fault. On the one hand I still have a slower sync speed with the Hub One, and with a SNRm of 6dB. I would have thought this noise margin should be higher as previously it was 6dB at 37Mb instead of the current 30Mb. On the other hand, it's not bouncing around like it was with the Asus router and is staying between 5.9 & 6.1.

Does anyone have any thoughts/suggestions?

Here are my BQM graphs for the last 3 days:
Monday (the large red part is when my IP address changed for some reason)
Tuesday
Today

Edited by deleted (Wed 03-Jul-19 15:13:12)

The ** Asus DSL range of modem/routers contain a Mediatek xDSL chipset.
I have never come across such a garbage DSL chipset that performs so poorly.

Frequently I see lines that were stable for years then suddenly they get hammered by DLM after switching to an Asus modem.

They are so bad OpenReach have blacklisted them from using G.INP as they don't follow the standards and it was causing issues with the fibre cabinets.

Changing modem will see G.INP return. It won't ever work with your Asus.

If you still can, return the Asus.
You could also use a separate modem and use the Asus as a router only.

** The newer Asus DSL-AC88U uses a Broadcom xDSL chipset and works flawlessly with G.INP.

Edited by j0hn83 (Wed 03-Jul-19 15:19:18)

Did Plusnet mention that there might be a charge if the engineer reports no fault found, or that it is/was with your equipment? I don't know if they still pass it on.

As it seems clear the problem was caused by your ASUS, your best bet would be just wait and see if it all returns to normal after a few weeks back on the Plusnet Hub.

Another problem could be that your line has now been banded. That can delay automatic correction. If you can get connection stats from the Hub then those can often give us a clue to whether or not that has happened.

Thank you both for your speedy replies. I wasn't aware of the Asus modem issues so that has given me food for thought. It was an Amazon purchase so I'm well within the return window if I need to send it back. I chose this specific router because I don't like unsightly external antennas on other models and because other brands such as TP-Link routers can't do bandwidth control on a per device basis, only traditional QoS.

I would be more than happy to use it just as a router but I have no idea which modem to buy. I'd even use the Hub One but AFAIK it can't be used in a modem-only mode, plus there are clearly better modems out there as even this Asus gave me the full upload rate of 10Mb which I've never seen with my Hub One in the 18 months I've had it.

With Plusnet when they book an engineer appointment you have to agree to the "engineer statement" that they read out before they will proceed, which includes a £65 charge if no fault found / fault in customer premises. Apparently £65 is only half the Openreach charge and PN absorb the rest. The problem I have is that I will be charged anyway if I cancel the appointment without giving 48hrs notice - impossible because the engineer is coming Friday.

To be honest I still think there is something going on as I think the SNRm should be higher than what it is given the lower sync speed. I've uploaded my Hub stats here but they are quite limited.

Edit: With regards to G.INP being blacklisted on some modems, wouldn't it just not turn on in the first place? It just seems strange how the connection initially worked well for a bit but then lost G.INP and went to pot after 24 hours.

Edited by deleted (Wed 03-Jul-19 16:35:14)

No idea, I just know OpenReach removed/blocked the Asus modems with Mediatek chipsets from using G.INP.

As far as I know it's the only modems they have done this with.

Swapping to a compliant modems brings G.INP back.

As for using the device as a router only, I wouldn't advise going down that route if it can be returned.
You need to use 1 of the Ethernet ports as a WAN port and the DSL modems are missing a couple features available on the RT variants.

In reply to a post by av709:

I have no idea which modem to buy

Personally I have been extremely happy with Draytek Vigor 130, although it's not the cheapest. It does baby jumbos so you can get 1500 byte MTU even over PPPoE, and does G.INP. Claims to support vectoring too, but my line doesn't have it.

The downstream sync and maximum don't look to me as though banding has been applied. Which is good news, as it's possible that by the time that engineer arrives DLM will have re-instated G.INP.

The bad news is that from what you say you are likely to have to pay the £65. Unless you are quite lucky. Or, if it was caused by the ASUS, and you had explained that it happened soon after you installed that, you might succeed in arguing that the support person should have thought of that before scheduling the visit.

In reply to a post by candlerb:

Personally I have been extremely happy with Draytek Vigor 130, although it's not the cheapest.

I bought one and it did worse to my line than the OP's ASUS seems to have done. I ended up with the line banded and it stayed so for many months at 55Mbps sync when it had always run at well over 65.

I did send the Vigor back a few days after discovering what it had done, and replaced it with a Billion 8800NL R2 modem/router. That stabilised everything, but the banding persisted.

In the end I managed to get DLM reset removing the banding, and over a short period got G.INP and a 3dB sync-time SNRM, taking me to sync's well over 70Mbps.

Note, the Vigor 130 does seem to give good results for most people, but I did find several who had the same experience as I did with it.

Value for money modem only wise IMHO the old Huawei HG612 3B (can often be got for £10-15 on auction sites) has always done me well on my connection and a few relatives.

A few people say they are old but they seem to give me a very stable sync.

In reply to a post by candlerb:

In reply to a post by av709:

I have no idea which modem to buy

Personally I have been extremely happy with Draytek Vigor 130, although it's not the cheapest. It does baby jumbos so you can get 1500 byte MTU even over PPPoE, and does G.INP. Claims to support vectoring too, but my line doesn't have it.

The Drayteks I've installed are very good.
All their VDSL kit sold in the UK supports vectoring.