[Betatester548]

Thanks for your help :)

We are going to try the test socket, to see if that improves the line stats / resolves the packet loss issue.

There are a few telephone extensions which could be affecting the line, potentially. It’s possible they were not installed well.

Do I just connect a microfilter to the test socket, with my Asus DSL N16 connected to it?

We have a NTE5C Master socket with VDSL MK4 faceplate.

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[Betatester548]

When I limit the upstream sync speed (frequency) heavily though (I think between 500-100kbps), the packet loss is always 0% (tested 5 times in a row).

I’m beginning to think the upstream signal just isn’t strong enough to provide higher upstream rates completely reliably. The line attenuation for the upstream bands is 18.5db and 28.9db.

I’m unsure if any of the routers I have would help to improve the attenuation.

I think we’d need an Openreach engineer to look at the line, and possibly the wiring in my street. I’m guessing that would cost hundreds.

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[Betatester548]

I do think it’s very strange that however small I set the MTU on my network adapter, there is always some packet loss (without altering any fundamental VDSL settings).

Lowering the MTU on the network adapter to 500 actually increases packet loss to anywhere between 2% to 11%.

This test doesn’t report actual packets lost though, only retransmission.

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[Betatester548]

I tried it about a week ago. It did has some initially (a few thousand if I recall) when it connected, at least with Bitswap enabled.

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[Betatester548]

I’ve tried a couple of Broadcom  based (Technicolor) routers. I’ve also got a TP Link VR200 with a Lantiq chipset. These routers all got some packet loss on the Mlab test on my line. I think there was some in game streaming services like google Stadia too.

With my Asus router, the line has been set to 9dB for both the downstream and upstream about 2 days ago, by Openreach’s DLM. I’ve got no CRC errors reported. With Telnet I can see some FEC errors, but these are not going up very often (not increasing whenever I use the connection).

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[Betatester548]

I wonder if a certain amount of packet loss is considered normal / fine on most FTTC/VDSL2 connections in the UK?

This graphic (admittedly from 2012) shows packet loss on various FTTC providers and Virgin Media’s network (see attachment).

My ISP (Cuckoo Broadband) uses Talktalk Business for their network backhaul apparently (same DNS servers too).

Which ISP are you using?

Note –  I’ve also tried altering the MTU settings on my router and network adapter, but no luck.

 

Attachments:

1. 

   packetloss_uk_broadband_isps_may2012.jpg
   

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[Betatester548]

Could you try running the Mlab test please, and let me know what results you get?

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[Betatester548]

I’ve realised that the speed test I’m using is probably either too sensitive, or possibly giving incorrect results. I only seem to get retransmission errors when I have higher upload sync speeds set on my router. Here is Mlab’s test:

https://speed.measurementlab.net/#/

I tested my connection at default sync settings and only got a tiny amount of packet loss in Google Stadia (less than 0.01%). Prioritising upstream packets via the QOS page seemed to resolve packet loss issues on Stadia.

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[Betatester548]

I tested my laptop with the WIFI protocol set to 802.11a, and consistently get 0% packet loss. This does not occur with the more modern 802.11ac protocol.

On my PC, generally 0.5-2% packet loss with an ethernet cable to my router/modem.

Is the 802.11a protocol correcting the errors / packet losses on my internet connection? Or, could something else going on?

I still get packet loss with other routers…

Here are my spectrum / VDSL bit loading graphs:

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[Betatester548]

I have been enabling QOS. Curiously, I find that heavily limiting the QOS settings, so that only 100-200kbps of upstream is received seems to to result in 0% packet retransmission /loss.

Could the problem I’m getting possibly be related to a QOS problem on my DSL-N16 router? Or, the firmware itself?

I tried disabling QOS entirely, but this does not fix the packet loss issue (I still get 1% or more packet loss).

Note – After resyncing my modem, I also found that the SNR Margin on both the downstream and upstream has been set to 9db, but there is still packet loss.

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[Betatester548]

Always seem to get packet loss regardless of the modem chipset used, unfortunately.

Quiet line test doesn’t work on my line, apparently you need a BT phoneline to do this.

Maybe I’ll try some other numbers.

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[Betatester548]

I need some advice regarding increasing the upstream noise margin, in the UK is the upstream noise margin always 6db? I’m doubtful changing the router/modem would help if upstream noise margin can’t be changed.

I’ve heard that some internet service providers can increase the upstream noise margin, on request is that true?

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[Betatester548]

Can the upstream SNR Margin be forced much higher with UPBO disabled? If so, how?

Is there a command to set this independently of the downstream SNR Margin?

Full VDSL band stats here:

There doesn’t seem to be much difference between the ‘Line’ and ‘Signal’ attenuation figures, which I’d assume is a good thing?

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[Betatester548]

I’ve left UPBO enabled, other settings in the DSL setting page are set to ‘stable’.

Disabling UBPO results in erratic upstream SNR margins that change every few seconds (packet loss also increases), often below 6db, so I always leave it enabled.

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[Betatester548]

Hi, thanks for getting back to me.

I have set my downstream SNR margin to either 8 or 7db. This seems to reduce downstream packet loss. Downstream sync is generally 35,000kbps or 40,000kbps.

Setting the downstream SNR margin to 15db  does not help to prevent upstream packet loss (nor does 30db) on my line, if the upstream sync rate is left at default (around 18,000kbps).

Upstream attenuation is 18.5db, downstream attenuation is 10.2db. I get a approx. 1-2 CRC errors on the upstream per hour, not much.

I’ve been using the latest official firmware. My  FTTC street cabinet is an ECI model.

Is there any Asus beta firmware that can force a higher upstream SNR margin?

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