FTTP Speed , Contention and Zen

A few weeks ago I upgraded to Zen's 900 package and I'm getting consistent speeds of 550-650. My question is how fibre works as I thought that the full speed should be obtained all the time until fibre becomes more ubiquitous? I live in the middle of no-where (and lucky to have fibre at all), but my neighbours are not massive speed freaks so I can't imagine contention comes into it (if it ever does?).

Any suggestions or explanations as to why I can't get full speed?

The rest of this post is about Zen, so feel free to ignore

I do have to say that I think Zen have lost the plot a little bit. After the upgrade was complete, I was still only getting 300 mbps down but the upload changed to 115mbps up so it was obvious (to me at least) that something had gone wrong in the regrading process or a limit on their system. But still asked me to use the ONT directly, run tests etc.. until a few days later I received an email saying a lot of the regrades were not done correctly.

With the latest issue of not getting 900 mbps, they again are asking for tests (which is fair enough), but the latest email from support says that although I have tried it on Windows, Mac, iPad via a router and plugged directly into the ONT I have to try it with Ubuntu. This is slightly crazy, hence my comment about Zen losing the plot ... unless of course I'm missing something and that Ubuntu will change everything (I only have it as a Virtual machine and REALLY can't be bothered to install it on a partition).

In reply to a post by boxst:

Any suggestions or explanations as to why I can't get full speed?

Achieving a full 900M+ can be tricky. Issues which can cause throughput limits include antivirus and poor quality NIC drivers.

I have certainly seen cases where a laptop running Windows achieves only 150M but Ubuntu on the same laptop fills a gig; therefore I think Zen's suggestion is reasonable. You don't need to install it - just run it directly from a "live USB" stick.

You haven't said explicitly, but I assume and hope that you are connecting directly with a CAT5e cable (although I don't know how you could do that with the iPad). And I guess you are using the Zen-provided router.

Contention at the fibre level is unlikely to be the issue: if it were, it would most likely vary around the clock, rather than giving you a consistent 550-650. Try late at night or early in the morning to confirm this. Contention at the exchange level, meaning Zen has insufficient interconnect capacity at your headend exchange, is more likely, although again I would expect it to vary around the clock.

You also didn't say how you were testing the speed (e.g. TBB speedtest? speedtest.net? Does Zen provide their own speed test?)

If you do a speed test with the TBB speedtester, and you share the graphs here, sometimes their shape can give a clue to the problem.

boxst

The issue can be with your devices and browser settings

Some devices are limited due to CPU / Drive / NIC capabilities

Some OS and browsers are much better than others at getting the best speeds

They are asking for you to use Ubuntu as they have confidence in it's abilities with their testing. This helps them diagnose the likely point of problem. Which may be your device and software capabilities or an issue on their network. They will be used to it being on the customer setup at the higher speeds and if you are getting 550-650Mb they will be more confident that their network is configured correctly.

Many ( if not most) ordinary devices and software are not capable of running at 900Mb ( Specialist builds are a different matter). and most distant internet servers will also not give this consistently to a user. However it is likely that two or more devices on the same connection will be able to get the full 900 shared between them. Many 900Mb setups will have 10+ devices using it at a time with no noticeable effect.

In reply to a post by boxst:

I only have it as a Virtual machine and REALLY can't be bothered to install it on a partition

You can run it off of a USB stick without installing it. Don't run it in a VM because it will be using a virtual networking driver which won't be as good and you'll also be CPU limited depending on how many CPU cores the VM has and how things are scheduled between the guest and host.

Some iPads can use a network connector via either the lightning or USB-C port and hardwire via Ethernet. I have this on my 2020 iPad Pro. It doesn’t use WiFi in this case. The USB-C port is rated to 10GB/s, though it’s actual speed I’ve never maxed out as I only have 5GBe available on the network.

In reply to a post by kitcat:

Some OS and browsers are much better than others at getting the best speeds

Oh yes, I forgot to mention the browser can also be a bottleneck.

Install the speedtest.net app (for your Mac, you can get it from the app store)

Most of the USB-C ethernet adapters I've come across top out at 1 Gbps. The only one I'm aware of that tops out at 5 Gbps is the QNAP one.

From there on in you're mostly in Thunderbolt-3 territory (pin compatible with USB-C but different host chipsets etc). Other Apple products like MacBooks use Thunderbolt 3 with a bus speed of 40 Gbps and 10 Gbps + 8K video + power delivery is a walk in the park.

The native Mac versions of the Speedtest client display the jitter results on the home screen but the Windows versions do not.

Jitter is quite a useful measure to have to hand, especially with VOIP. Always wondered why ookla differentiated the clients in this way.