tboorman,

Thank you for that; it is very helpful to know and it confirms my suspicion that Zen will eventually sort it out.

My browsing/web page loading has generally got a lot better, (which is the first thing that I notice before i hit the speed tests) and my speeds may have improved somewhat but its not reliable and highly variable.

Are you now seeing consistently good speeds?

Regards,
Fido

The OpenReach engineer took a light reading from your fibre during install. Any poor splices would have shown up. They can't go ahead if the light levels aren't in spec.

Your ONT is connected at 2.4Gb/s down and 1.2Gb/s up. It's never the issue.
Your ONT is connected at 1Gb/s to the router. If there was an issue there it would default to 100Mb and none of your speed tests would be above 100Mb.

Your issue is entirely contention. It can't be an issue with the local fibre or light loss or anything similar. The ONT wouldn't connect or would be extremely intermittent.

Ask Zen if they have given your line the elevated traffic status fix they were giving other users on the 900Mb package.

Edited by j0hn83 (Sat 10-Oct-20 17:11:40)

In reply to a post by j0hn83:

The OpenReach engineer took a light reading from your fibre during install. Any poor splices would have shown up. They can't go ahead if the light levels aren't in spec.

He did not take a light reading from inside the house next to the ONT.

I asked him to push the fibre wire the very short distance through the hole in the house wall to the ONT location and then for some reason he cut off about 15 feet from the new fibre wire that was coiled up outside , on the path, next to the house on his arrival and instead of just pushing some of that fibre wire just another 11 inches through the house wall to the ONT location, (as I had asked him to), he used a different short length of wire through the house wall and he put some form of spliced joint, (probably a field splice), in a big junction box that he fitted on the house wall. about 60cm. above the path. - If had then checked the light readings from inside the house at the optical plug I would have said OK but he did not do that and since he did not take a light reading from inside the house I cannot see how he took a like reading that covered the whole line including the sliced joint that he made and it is his spliced joint that I am less comfortable with because he did not fill me with confidence. - (If he was doing watch repairs he would probably use a big adjustable spanner and a lump hammer). - I knew from my old copper line that some Openreach engineers are very good, they always do a an excellent very neat job using the proper wiring and making good joints and some are much less able.

In reply to a post by j0hn83:

Your issue is entirely contention. It can't be an issue with the local fibre or light loss or anything similar. The ONT wouldn't connect or would be extremely intermittent.

After reading the latest post from tboorman, (who apparently had similar issues), I am persuaded that contention could be a major part of the problem but since at 4:00AM it is was still not good and I would like someone to test the line from inside of the house to rule that out as if it is not checked now it will never get checked

He installed it as he should, not how you wanted.

New deployment method isn't 1 continuous length of fibre but there is supposed to be a splice on the wall outside.

There's nothing wrong with your light levels, or your splice outside, or any other part of your fibre circuit.

That would NOT SLOW YOUR THROUGHPUT. Not by 1Mb or 100Mb.
It would cut the service off, or work perfectly.
There is no in-between.
It could be intermittent, but it would be on or off.

It's contention, or poor configuration on Zens or BT Wholesale part.
Forget about the fibre outside your house, it's fine.

In reply to a post by j0hn83:

It's contention, or poor configuration on Zens or BT Wholesale part.
Forget about the fibre outside your house, it's fine.

jOhn83,

You have made the case very ably and well: I accept your view that it must be contention and I thank you for making it so clearly and so well.

I will contact Zen again on Monday and I will persuade them to sort it out for me.

Thank you for your assistance,

Regards,
Fido

I have not been constantly checking, but on the occasions that I have, my download speed has been 800 Mbps+.

I would also not use the speed test site that Zen have given you - they initially told me to use that too, but subsequently told me to use the ones that I gave in my earlier post (the one that they have given you is actually just a custom version of Speedtest.net).

In reply to a post by j0hn83:

He installed it as he should, not how you wanted.

New deployment method isn't 1 continuous length of fibre but there is supposed to be a splice on the wall outside.

There's nothing wrong with your light levels, or your splice outside, or any other part of your fibre circuit.

That would NOT SLOW YOUR THROUGHPUT. Not by 1Mb or 100Mb.
It would cut the service off, or work perfectly.
There is no in-between.
It could be intermittent, but it would be on or off.

It's contention, or poor configuration on Zens or BT Wholesale part.
Forget about the fibre outside your house, it's fine.

Sorry to burst your bubble but that is not correct. In extremely rare circumstances fibre optical links can stay up but pass traffic at significantly below the advertised link speed due to TX/RX errors. Basically you have to be right on the knife edge for to manifest in this manner. In normal circumstances on a modern switched link TX/RX errors should be zero or very close to zero.

In my career I have only ever seen this once on fibre optic cable. I have also seen it happen a couple of times on copper ethernet too.

However I must stress it is extremely unlikely to be the case here and I would expect the monitoring platform that Openreach use to be flagging these errors any way, and them being investigated and fixed proactively.

Fibre optics links can.
GPON won't though.

It's a 2.4Gb/s link or nothing.

Tx/rx errors anywhere near high enough to cause the slowest of slow downs will break the link.
The OLT will break the link if the ONT doesn't.
A GPON link behaving as you suggest can screw the whole PON.

Even in a point to point link in your own words "extremely rare circumstances".

The day that a poor splice causes a 50% drop in throughput on GPON is a cold day in hell.

The OP was fixated on the local fibre loop because he/she thinks the engineer was incompetent. The only reason given for this is the engineer cutting a fibre cable and splicing it (like he's meant to).
Sometimes it's just easier to tell people fixated on the highly improbable, that's it's just impossible.

The chances of ever seeing massively reduced throughput on OpenReach's GPON lies somewhere between zero and none.

In reply to a post by j0hn83:

A GPON link behaving as you suggest can screw the whole PON.

At the present time; ours is the only house in our group of houses that has FTTP.

That said; yesterday, (Friday), two Openreach Engineers were doing things in the underground chamber at the edge of our front garden and in the underground chamber of the house opposite, (the house opposite has an underground chamber and next door also has an underground chamber) - Today, (Saturday), another Openreach Engineer was messing around in the underground chamber at the edge of our front garden but he did not go elsewhere. - Yesterday, we left them to it in case they were doing work for a neighbour with just a copper line and today, just after we noticed him, he put the cover back on and he left before we could speak with him. - Why would he be out checking on Saturday if he was not looking for some form of fault ?

Maybe it is a pure coincidence or just maybe something is messing up the PON and they are faffing searching around for the cause.

Why would most Openreach Engineers carry out a light test during an installation if it was irrelevant as they could all do what the engineer who fitted our FTTP did and they could just look for an LED light on the ONT, before considering that everything is OK and then leaving without a light test.

The entire build is audited before it goes live for orders.
Light levels measured up to the CBT.
An engineer plugged your fibre in to the CBT, no splicing at that point.

The engineer then spliced your cable on the external of your property.
It's not a cheap splicer he used either.

There's probably a copper DP, a CBT and a splitter in that chamber.
My nearest chamber has 2 splitters, a CBT and a copper DP.
There's an engineer in it every 2nd day.
My developments been live in FTTP for a couple months but MJ Quinn were back this week (they installed it on behalf of OpenReach months ago) in all the chambers.
Doesn't mean something's wrong though.

Engineers take light levels at installations because it's good practice.
If the light readings are too low it can cause your ONT to completely or intermittently lose sync with the OLT.
They aren't irrelevant to installs altogether, just irrelevant to low speeds.
What work could they possibly be doing to your FTTP that wouldn't cause you to lose connection on the ONT?
Was he just looking at the fibre to see if it looked right?

The ONT connects to the OLT at over 2.4Gb/s. It isn't variable, it can't connect at a lower speed.
It drops the connection to the OLT or stays connected.

That 2.4Gb/s is shared by all properties on the splitter (upto 32).
Every ONT on the splitter is connected at the same rate, and you all have the exact same data running over each others fibre.
It could theoretically be contention in the local PON.
It can't be a bad splice though.

There's probably a dozen Zen users who've posted issues with their 500 and 900Mb packages.
Why are you so obsessed over the 1 part of the network I've NEVER known to cause speed issues.

Call Zen.
They should send an OpenReach engineer first (it's standard).
He/she will check everything's ok.
Then they will send it up the chain to BT Wholesale.

Your Speedtest alone screams contention.
The graph from the TBB test you posted above is extremely typical of contention.

The very knowledgeable MrSaffron (staff here, he recently received an OBE for his work in broadband) already gave you that exact same answer but you are absolutely fixated on something else.

https://forums.thinkbroadband.com/zen/t/4661128-does...

If the light levels are too low then it simply refuses to link up

Getting full speeds from a Nokia ONT here. Whether they fusion or mechanical spliced no idea, as kept out of the way during install due to social distancing.

The shape suggests a throughput issue somewhere and not a light issue with the local fibre.

He sees hundreds of these graphs a week.

I wish you the best with your low throughput issues. I won't be posting any further in this thread it's getting very repetitive.

Edited by j0hn83 (Sun 11-Oct-20 01:29:28)