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Giganet (CityFibre) 60% daytime drop in speeds

Bytesize2002

Casual Member
I am subscribed to the Giganet FullFibre900 service.

In the weeks following installation I was achieving a consistent >900Mbps speedtest result.

However I'm now experiencing very slow speeds of 350Mbps during the working day, and can only achieve >900Mbs results during the early hours of the morning.

See this example, where speeds are >900Mbps at 02:30 but drop to 350Mbps at 09:50.

My tests are using a hardwired ethernet cable directly into the back of the Amazon Eero Pro 6E Router supplied by Giganet. I am not using WiFi.

Giganet-Speed-Drop.png


The speedtest result from the Amazon Eero router shows a link speed of >900Mbps:

EerosSpeedtest.webp


I tried lots of different combinations of Speedtest locations, also tried Fast.com and others. All report similar speeds of 350Mbps during the day.

The results are so consistent day-to-day that I wonder if I'm being rate limited?

I understand that I don't receive a 1:1 service and speeds of 900Mbps are a target not a guarantee, but I feel that speeds dropping by 60% to 350Mbs is excessive for a 900Mbps service.

Does anyone else experience this problem with Giganet, or CityFibre in general?
 
Most likely to be ISP-side network congestion, assuming you're testing on an unloaded connection via a wired link to the router. As they add new users, then eventually there will come a point where performance may become more variable unless they spend a bit extra to boost capacity in the location.
 
Hi @Mark.J, thanks for replying.

Yes, it could well be contention.

It just seems suspiciously consistent - almost exactly 350Mbps down / 260Mbps up every time I test during the day.

To me it looks more like rate limiting (i.e a consistent throughput ceiling) rather than contention (which I would expect to fluctuate more based on demand at that specific time).

I've raised a ticket with Giganet to see what they say, but was curious to see if anyone else had experienced anything similar.

1693311818845.png
 
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Hi @Mark.J, thanks for replying.

Yes, it could well be contention.

It just seems suspiciously consistent - almost exactly 350Mbps down / 260Mbps up every time I test during the day.

To me it looks more like rate limiting (i.e a consistent throughput ceiling) rather than contention (which I would expect to fluctuate more based on demand at that specific time).

I've raised a ticket with Giganet to see what they say, but was curious to see if anyone else had experienced anything similar.

View attachment 8056
You should measure latency as well. Also experiment changing the test server, I know for a fact some of the ones I use can't get 940/940Mb that I usually get with Community Fibre. Are you sure you are not using a VPN to your workplace? Check your public IP throughout the day.
 
Hi @Bytesize2002 ,

Sorry to hear of the slow downs.
There's nothing in our network pointing to congestion, nor do we apply any throttling/rate-limiting.

Are you able to share the ticket number as a DM?
We'll take a look further for you.

As others have shared, please ensure you're not inadvertently on a corporate VPN, as your traffic will be routing elsewhere and you'll be limited to the capacity on that network routing.

Thanks
Matt
 
Hi everyone,

I managed to find the root cause - and it was a strange one!

It seems the Amazon Eero Pro 6E Router and Realtek ethernet devices have a port speed negotiation issue.

I was testing from a Dell laptop wired directly to the Eero using cat5e. The Dell had an internal ethernet interface (1Gbps) and I also tried an external USB ethernet interface (2.5Gbps). Both ethernet adapters used Realtek chipsets.

By default, both Realtek devices have automatic negotiation enabled:

1693390965260.webp


Windows reported the auto-negotiated link speed to be 1Gbps full duplex, but approximately 75% of the time I ended up with just 350Mbps down / 250Mbps up throughput on the speedtests.

However when I changed the setting from Auto Negotiation to explicitly set 1Gbps Full Duplex, then I got the full line speed of around 925Mbps down / 930Mbps up:

1693391080315.webp


I tried switching between the 1Gbps and 2.5Gbps ports on the Amazon Eero Pro 6E Router but experienced the same problem unless I explicitly set the port speed.

A mystery why this is a problem, but at least I figured out the root cause!
 
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Hi everyone,

I managed to find the root cause - and it was a strange one!

It seems the Amazon Eero Pro 6E Router and Realtek ethernet devices have a port speed negotiation issue.

I was testing from a Dell laptop wired directly to the Eero using cat5e. The Dell had an internal ethernet interface (1Gbps) and I also tried an external USB ethernet interface (2.5Gbps). Both ethernet adapters used Realtek chipsets.

By default, both Realtek devices have automatic negotiation enabled:

View attachment 8070

Windows reported the auto-negotiated link speed to be 1Gbps full duplex, but approximately 75% of the time I ended up with just 350Mbps down / 250Mbps up throughput on the speedtests.

However when I changed the setting from Auto Negotiation to explicitly set 1Gbps Full Duplex, then I got the full line speed of around 925Mbps down / 930Mbps up:

View attachment 8071

I tried switching between the 1Gbps and 2.5Gbps ports on the Amazon Eero Pro 6E Router but experienced the same problem unless I explicitly set the port speed.

A mystery why this is a problem, but at least I figured out the root cause!
I will put my money on the cable. Most of the connectivity issues come down to bad cable. Buy a Cat7 patch cord (see one that I used before and has great reviews) and try again.

https://www.amazon.co.uk/gp/product/B08KWJNGG9
 
Hi @Ionide, take a look at this thread for my experience with latency on Giganet:


tl;dr; 10ms ping seems to be "normal" as Giganet seem to breakout in London, so the latency is the speed-of-light restriction from me to London. I'd love it to be lower, but I'm not unhappy with it.
 
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Hi everyone,

I managed to find the root cause - and it was a strange one!

It seems the Amazon Eero Pro 6E Router and Realtek ethernet devices have a port speed negotiation issue.

I was testing from a Dell laptop wired directly to the Eero using cat5e. The Dell had an internal ethernet interface (1Gbps) and I also tried an external USB ethernet interface (2.5Gbps). Both ethernet adapters used Realtek chipsets.

By default, both Realtek devices have automatic negotiation enabled:

View attachment 8070

Windows reported the auto-negotiated link speed to be 1Gbps full duplex, but approximately 75% of the time I ended up with just 350Mbps down / 250Mbps up throughput on the speedtests.

However when I changed the setting from Auto Negotiation to explicitly set 1Gbps Full Duplex, then I got the full line speed of around 925Mbps down / 930Mbps up:

View attachment 8071

I tried switching between the 1Gbps and 2.5Gbps ports on the Amazon Eero Pro 6E Router but experienced the same problem unless I explicitly set the port speed.

A mystery why this is a problem, but at least I figured out the root cause!
I've done a lot of playing recently with the RTL8156, and it's one hell of a minefield. On Windows make sure you update the driver from the Realtek website, as the version bundled with the OS is from 2017.
It may not fix the negotiation issues, but it definitely fixes performance issues when you exceed gbit.

On Linux there are other issues but I assume that's irrelevant for now.
 
Hi @Ionide, take a look at this thread for my experience with latency on Giganet:


tl;dr; 10ms ping seems to be "normal" as Giganet seem to breakout in London, so the latency is the speed-of-light restriction from me to London. I'd love it to be lower, but I'm not unhappy with it.
giganet have no exit fees, so you can leave and get on with another isp with a lowerping but how far you are away from london does matter.
 
Most of the connectivity issues come down to bad cable. Buy a Cat7 patch cord (see one that I used before and has great reviews) and try again.

https://www.amazon.co.uk/gp/product/B08KWJNGG9

There's no way that's cat7 cable.

My advice for cables is:
1) ignore things like "CAT 7" / "CAT 8" - if they make a song and dance about it (like its the first thing in the title), it's likely not true.
e.g. that listing lists operating frequency at 500Mhz, which is CAT 6a.

2) Don't buy a flat cable, they're not to spec. (the white option on this link is flat)

3) If it looks like they're trying to push "gold connectors" - ignore, as it makes no difference. It seems interesting to me they've picked to make the 8p8c/rj45 "gold" coloured, I'm guessing to fool people who buy "gold" HDMI and audio cables.

Even better when they add these to CCA cabling. :rolleyes:


Just swap it out for another cable, as long as it has all 8 pins connected unless this cable is circling the house before you plug it in - it'll be fine.


Realtek drivers are ... mmm :D

Congrats on at least finding the cause! I do like weird issues like this (when they're fixed anyway)
 
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I've done a lot of playing recently with the RTL8156, and it's one hell of a minefield. On Windows make sure you update the driver from the Realtek website, as the version bundled with the OS is from 2017.
It may not fix the negotiation issues, but it definitely fixes performance issues when you exceed gbit.

On Linux there are other issues but I assume that's irrelevant for now.
Yeah the OS inclusive driver is really old.
 
Great to hear you got this sorted @Bytesize2002. A strange one, but that is not something we have come across before as auto neg should work perfectly.
I'd try a different computer/network card to help rule things out further.
Thanks for your explanations.

Matt
 
giganet is worst provider period be aware crap latency unprofessional cancel migration order for no reason will report ofcom
 
giganet is worst provider period be aware crap latency unprofessional cancel migration order for no reason will report ofcom
you can leave giganet without paying any fees, just order from another ISP like TT.
 
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