Upload speeds vary so much, while download speeds are very stable - why?

[TheLyppardMan]

I have Full Fibre 900 with Zen Internet in the UK (using the CityFibre network). I note that the download speeds are very consistent, but the uploads speeds are not (see attached screenshot). Can anyone tell me why this might be?

I have enquired of Zen and this is what they told me:

"To answer your question regarding the upload speed, this is within the scope of City Fibre and is out of our control; our apologies for any inconvenience. We do not offer a minimum upload speed on our City packages as detailed below. Further information can be gained by contacting the supplier themselves however"

So, as suggested, I went to the CityFibre website and saw this on their contact page:

"Please do not complete this form if your query is related to broadband service issues or outages, please contact your broadband provider directly to help resolve these issues."

So I'm obviously going round in circles and still have no idea about a possible reason for the phenomena I am experiencing. If anyone on this forum has a possible explanation, I'd be interested to hear it.

 

[L&LD]

Time of day.

Server used for test.

Others using same connection (on ISP side).

Position of dancers at the feet of the moon.

 

[TheLyppardMan]

So why are the download speeds not affected?

 

[L&LD]

They're probably much more overprovisioned than the upload speeds (which don't 'sell' well).

 

[Ripshod]

Your contract is with Zen. It's their responsibility to contact Cityfibre and investigate.

 

[TheLyppardMan]

Your contract is with Zen. It's their responsibility to contact Cityfibre and investigate.

I sent them a message after viewing your post. This was their reply:

"As advised by my colleague, there is no minimum upload speed guarantee on our City Fibre packages therefore we have no avenue to investigate this further."

 

[TheLyppardMan]

I've replied to the e-mail from which I extracted the above quote. This is what I have said:

"Thank you for your reply.

I understand your comment that you "have no avenue to investigate this further" and that "there is no minimum upload speed guarantee", but surely when Zen was setting up its service to use CityFibre, there would have been a discussion about data transfer speeds (down and up). Even if that were not the case, which seems unlikely to me, I would have thought that CityFibre ought to be able to provide you with enough information to answer my question, particularly since I am unable to follow Gavin's suggestion that "Further information can be gained by contacting the supplier themselves", which obviously I am unable to do, as CityFibre won't deal directly with ISP customers, as noted in my reply yesterday to Gavin's last message."

 

[sfx2000]

They're probably much more overprovisioned than the upload speeds (which don't 'sell' well).

that's one of the issues with consumer accounts (vs. business) - a promise to deliver "up to" vs a committed minimum...

I feel bad for OP as nobody is stepping up, rather they're shifting the blame to someone else...

:|

 

[Tech9]

I also don't see what exactly the issue is. Residential lines are not guaranteed. I have three residential lines and although consistent most of the time they also slow down from time to time. This doesn't affect the user experience though since the speed is enough for what my family is doing online. The more people on the same shared connection run speed tests regularly the worse it gets. This is a wasted bandwidth. Also the built-in GUI speed test may not be accurate.

 

[TheLyppardMan]

I also don't see what exactly the issue is. Residential lines are not guaranteed. I have three residential lines and although consistent most of the time they also slow down from time to time. This doesn't affect the user experience though since the speed is enough for what my family is doing online. The more people on the same shared connection run speed tests regularly the worse it gets. This is a wasted bandwidth. Also the built-in GUI speed test may not be accurate.

Curiousity is the issue! I like to ask the question "why?" and "how?" If humanity weren't inherently-curious, then we would still be living in the so-called "Dark Ages" or worse. But then I suppose, at least we wouldn't now be in a situation where destruction is occurring around the world at an alarming rate and we could all be wiped out by the press of a war-monger's button on the nuclear trigger.

Anyway, back to the main subject. The tests I've made from the router are not normally that frequent, so the effect on bandwidth would be minimal. The results are similar to what I get if I connect my Wi-Fi 6-compatible laptop to the router via an Ethernet cable, but much more convenient as they aren't device-specific.

 

[Tech9]

I like to ask the question "why?" and "how?"

The answer is simple - residential lines are not guaranteed. The speeds are "up to". This is what your ISP advertises. You knew it's "up to" when you signed up for the service. I didn't see anywhere on Zen Internet website Gigabit up/down guaranteed. In this case the answer you have received is correct - there is nothing to investigate.

 

[sfx2000]

I feel bad for OP as nobody is stepping up, rather they're shifting the blame to someone else...

Just to note - my point was the operators not playing nice - the forum members have, as usual, been very supportive..

 

[TheLyppardMan]

The answer is simple - residential lines are not guaranteed. The speeds are "up to". This is what your ISP advertises. You knew it's "up to" when you signed up for the service. I didn't see anywhere on Zen Internet website Gigabit up/down guaranteed. In this case the answer you have received is correct - there is nothing to investigate.

I know that only the download speed is guaranteed (in my case, 450 Mbps on their Full Fibre 900 service). The point I was trying to make is that while the download speeds are consistently above 900 Mbps, the upload speeds are anything from 75 Mbps to over 800 Mbps and I was just curious to know why there is such variability with the upload speeds but not with the download speeds. So at the moment, there is no answer to my question, but just to clarify, I am not dissatisfied with my ISP. On the contrary, I think they are great and I shall remain with them as long as they stay that way.

 

[Crimliar]

If our OP hasn't done this already, it may help if they use a single-set SpeedCheck server.

 

[TheLyppardMan]

If our OP hasn't done this already, it may help if they use a single-set SpeedCheck server.

Sorry but I don't know what you mean by this.

 

[Crimliar]

When you use SpdMerlin you can set the server you want to use for the test, so that it will always use the same server. On the regular speedtest.net webpage you can see the current server Id by mousing over the name of the server, which you can then enter into SpdMerlin. As I'm no longer using that extension I can't remember if you have to access SpdMerlin through ATM to get that option, but I think it's there in the WebUI.

 

[TheLyppardMan]

I'm trying the official firmware at the moment, to see if that makes any difference, so I don't currently have access to the amtm scripts. I'm in contact with Zen Internet as well and I've promised to report back to them when I've made some more tests over the next few days.

These are my latest speed test results since changing to the official (latest) firmware:

 

[TheLyppardMan]

I've run some more tests this morning (22/01/24) and got variable results using the router's speed tester, but much more consistent results of over 900 Mbps (down and up) from the Ookla website, using an Ethernet connection. I've also run a test over Wi-Fi for comparison.

 

[Diablo99]

Use the Speedtest app, downloaded from Ms store, use a good CAT cable 5 or 6 & Windows pc.
Disable temp. VPN (if you have it) & AV, Fw etc. or Is.

Good luck

 

[Tech9]

These are my latest speed test results

And they look much better. What’s the conclusion? Stop fiddling with your router.