In reply to a post by ft247:

There is still more to look at on upload speed to distant servers - there are a number of cases where the distant server will give an easy 940Mbit download but struggle to receive more than 300 from me.

How "distant" in terms of milliseconds RTT?

If this is a single threaded upload, then it's almost certainly due to a tiny amount of packet loss somewhere along the line limiting TCP throughput.

https://en.wikipedia.org/wiki/TCP_tuning#Packet_loss

In reply to a post by Pheasant:

How are you getting on with ROS 7.x ?

Mine is the SFP+ model and running 6.48.4 - it's only the mostly copper 2004 which is 7.x only.

I'm getting close to 'happy to try v7' territory, but need a bit more free time on my hands before diving in.

In reply to a post by candlerb:

How "distant" in terms of milliseconds RTT?

If this is a single threaded upload, then it's almost certainly due to a tiny amount of packet loss somewhere along the line limiting TCP throughput.

Less than 50ms - in many cases less than 30. I think it starts appearing around the Scotland/Germany level of distance from London. Will try to post back soon with more detail.

In reply to a post by ft247:

Less than 50ms - in many cases less than 30. I think it starts appearing around the Scotland/Germany level of distance from London. Will try to post back soon with more detail.

At 20ms RTT, a single TCP stream will be limited to ~300Mbps by packet loss of just .0004%, or 1 in 250,000 packets

1460/(.02*sqrt(.000004))*8 = 292,000,000

In reply to a post by ft247:

My area is very recent expansion for CF, and borders an area that has 3Gbit available.

My area does not have 3Gbit for sale, which is the same situation as another new CF build area I'm aware of.

I have the 1Gbit service and an XGS-PON ONT.

To me, this means there is another reason for restricting 3Gbit sale - either commercial, or limited backhaul.

Community Fibre just went live in my area 2 days ago and I can confirm 3Gbit is available to order! So indeed it is XGS-PON that is being used.

One thing that is also interesting is that now my other 2 apartments one in Shoreditch and the other one in Sidney Street also now show up 3Gbps as available to order when previously they would only show as 1Gbps available.

It is quite possible that if you now check the website for your postcode you will also see 3Gbit available for sale if you select the 24 month contract package.

The fact that they all show 3Gbps available suggests that indeed they all had XGS-PON ONT but simply as you say the backhaul limitation was probably something that needed addressing.

Anyway, now I have to wait for my TalkTalk FTTC contract to end in February 2022 and then I'll switch to Community Fibre. The new service will surely be a much better service than FTTC even if XGS-PON wasn't available. But now it is much more reassuring!

Sorry to bump this old thread but I have the same issue.

Here's the current TBB graph:

My Broadband Ping

Ignore the big red blocks, that's just me fiddling/trying to find the correct IPv6 address to ping (apparently my public IPv6 address is on 2nd hop, not 1st hop).

There's consistent packet loss between 0% and 5% that's only seen in IPv6. IPv4 has no packet loss at all.

I also ran tracert (via WinMTR) and the below is what I found out so far:

IPv6
IPv4

As WinMTR constantly sends out loads of pings, I expect some loss to some degree as result of servers not responding to some of my constant pings. The %% (meaning packet loss) as observed in IPv6 result is huge compared to IPv4 result.

I've looked through the entire thread, it seems like nobody has found a solution yet? Or did I misread something?

I cannot speak for the service yet. When I previously posted in October 2021 my Community Fibre service didn't go live until December 2022!

So, due to this uncertainty at that time and the fact that TalkTalk FTTC price hiked my service to £40 a month, I switched to BT.

Here I am still on BT FTTC and am generally happy with their service. I have not joined Community Fibre yet as I said I was because I haven't yet found a good deal. The good deals that were on offer were available when the service wasn't yet live in my building.

It seems the packet losses are reported by other users as well. I'm assuming that the problem was resolved but came back again. Hopefully it will be fixed again. Are you testing this with WiFi or Ethernet cable?

I'm reading that this problem is being experienced for IPv6 but not IPv4. Also, I read that Community Fibre have a CGNAT restriction on all packages except for the 3Gbps so not sure if that also has an impact on packet loss and ping performance.

I'm seeing a similar IPv6 packet loss - here is the link to my graph

Unfortunately I can't monitor IPv4 as I am behind CGNAT.

I used to get the same thing when I used monitor the IPv6 Address of the router, yet the Routers Gateway has no packet loss / red marks.
It got to a point I was checking a lot even though there was no actual issues on the connection, so I just disabled them and just monitor my IPv4 Address (shown in my Sig).

But I have just temporary (for the next couple of days) restarted up my IPv6 Monitors shown below:
My Routers IPv6 Connection: Router IPv6 Connection
As well as the first hope out (i.e. Routers IPv6 Gateway) First IPv6 Hop out / Routers Gateway

As you will see the routers IPv6 Monitor will have the little RED spikes on top where as the first hop out (router's gateway) is fine, so something is up.

Also traceroute from my PC shows timeouts on some of the Hops, that's could still be fine, not all hops respond to pings.

I know when I last looked at this a couple of years ago I did speak to somebody at CFL and they couldn't see any packet loss or any issues that would cause this.
I know I am not seeing or having any issues over IPv6 and I use it a lot.

tracert google.co.uk

Tracing route to google.co.uk [2a00:1450:4009:826::2003]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  [ROUTER IPv6]
  2    <1 ms     1 ms    <1 ms  [ISP GATEWAY]
  3     2 ms     1 ms     1 ms  lag-6.acc1.med.lon.network.as201838.net [2a02:6b60:0:1:4::59]
  4     *        1 ms     2 ms  lag-17.edge1.thn.lon.network.as201838.net [2a02:6b60:0:1:4::170]
  5     2 ms     1 ms     1 ms  2001:4860:1:1::814
  6     2 ms     2 ms     2 ms  2001:4860:0:1::7e3f
  7     2 ms     2 ms     2 ms  2001:4860:0:1::73c5
  8     2 ms     1 ms     1 ms  lhr48s48-in-x03.1e100.net [2a00:1450:4009:826::2003]

Trace complete.

The as201838 are the Community Fibre Hops and those are the ones that I am having issues with that are timeouts due to Traceroute on my router does get a response now and then and the second as201838 (lag-17.edge1.thn.lon.network.as201838.net [2a02:6b60:0:1:4::170]) that has the highest packet loss.

But as I said I am not seeing or having any issues over IPv6.

---
Paul

Thanks, Paul

When running WinMTR I get packet loss after the ISP Gateway and going to 2a02:6b60:0:1::10 which you point out is still within CFL.

I will continue to monitor for now, but as you say, everything seems to work OK.