G.Fast throughput

Since December 2019 I have had g.fast with TalkTalk, it only dawned on me a few weeks ago that I have never reached the guaranteed 290mb downstream. The most I have reached is 240mb, and whilst I am lucky to have that I am paying for more and feel entitled to it.

I have a Huawai MT992 which the TalkTalk Wifi Hub connects, I have run speed tests during peak and non-peak times, over wireless and wired with just my laptop connected.

Have worked in tech support for years so understand how to troubleshoot.

TalkTalk have taken a look, they see 350mb when testing to the router. They sent me a replacement router which didn't improve things at all.

My line is short, when the BT OR engineer installed the line his equipment synced at 500mb.

So is the hardware at fault here? Do I spend money on a new router to connect to the Huawai? I'll need one that has a WAN port of course. There is a limited selection of routers which support g.fast natively.

Any suggestions most welcome.

G.fast are pretty useless. It will drop your speed quickly than FTTC

In reply to a post by adslmax:

G.fast are pretty useless. It will drop your speed quickly than FTTC

Like I said, all speed tests come back at 350mb from TalkTalk to the router. Speeds have remained at a max of 240mb, no dropping.

Also like I said, my line length is ridiculously short.

Anyway, as per my 1st post. I'm looking for suggestions, your post is a critique.

Edited by deleted (Wed 30-Oct-19 12:54:55)

In reply to a post by Glovepup:

In reply to a post by adslmax:

G.fast are pretty useless. It will drop your speed quickly than FTTC

Like I said, all speed tests come back at 350mb from TalkTalk to the router. Speeds have remained at a max of 240mb, no dropping.

Also like I said, my line length is ridiculously short.

Anyway, as per my 1st post. I'm looking for suggestions, your post is a critique.

If your throughput is 240 then there ain't no way they are getting 350 , maybe they are referring to the sync speed sounds like it to me, thick tt support

In reply to a post by Glovepup:

Since December 2019 I have had g.fast with TalkTalk, it only dawned on me a few weeks ago that I have never reached the guaranteed 290mb downstream. The most I have reached is 240mb, and whilst I am lucky to have that I am paying for more and feel entitled to it.

A few things to check.

1. When you say you are getting 240Mbps, is that the sync speed, or the achieved data transfer speed to some remote site?

If you have your own G.fast modem, what sync speed does it say you have? Does the dslchecker show "Observed Speeds", like it does for VDSL?

The sync speed is the raw bit rate between you and the G.fast modem in the cabinet. A throughput speedtest is only measuring the payload of packets, and doesn't count the TCP/IP headers. This alone limits payload speed to about 96% of sync speed.

2. If it's a throughput test, the bottleneck could easily be your PC or whatever it is you're testing from. First thing of course to check is that you are testing over a gigabit wired ethernet connection, not wifi. But I've seen many Windows machines which struggle to handle 200Mbps, due to poor quality of network drivers etc. Swapping to a different NIC can make a big difference - Intel's own-brand PCI NICs work very well.

I have also found some machines where they can fill a gig if you boot them into Linux instead of Windows - apparently Linux has better drivers for some NICs. Try booting from a Linux "live CD".

Problems are not limited to Windows. Speedtest.net is very flash-heavy, and my 2015 Macbook Pro laptop struggles to reach 250M; I can see the CPU load flatlining at 100% in "Activity Monitor" during the test. But running iperf3 from the command line I can easily fill the available bandwidth (or a gigabit to another local device).

3. It could also be a limitation of the provided router, although if you're using a Talktalk-provided one you'd think they'd give you one that's up to the job. If it provides a way to monitor its CPU utilisation, and it sits at 100% during the test, that would give you a clue.

I have a Mikrotik HeX PoE, and it's relatively under-powered (800MHz single CPU). If you tune it to use its "fasttrack" mode, it can do about 900Mbps of IPv4 - or equivalently, I see ~35% CPU load during a 300Mbps speedtest. Unfortunately there's no fasttrack for IPv6 yet, and with v6 it only handles 250-300Mbps.

In reply to a post by candlerb:

In reply to a post by Glovepup:

Since December 2019 I have had g.fast with TalkTalk, it only dawned on me a few weeks ago that I have never reached the guaranteed 290mb downstream. The most I have reached is 240mb, and whilst I am lucky to have that I am paying for more and feel entitled to it.

A few things to check.

1. When you say you are getting 240Mbps, is that the sync speed, or the achieved data transfer speed to some remote site?

If you have your own G.fast modem, what sync speed does it say you have? Does the dslchecker show "Observed Speeds", like it does for VDSL?

The sync speed is the raw bit rate between you and the G.fast modem in the cabinet. A throughput speedtest is only measuring the payload of packets, and doesn't count the TCP/IP headers. This alone limits payload speed to about 96% of sync speed.

2. If it's a throughput test, the bottleneck could easily be your PC or whatever it is you're testing from. First thing of course to check is that you are testing over a gigabit wired ethernet connection, not wifi. But I've seen many Windows machines which struggle to handle 200Mbps, due to poor quality of network drivers etc. Swapping to a different NIC can make a big difference - Intel's own-brand PCI NICs work very well.

I have also found some machines where they can fill a gig if you boot them into Linux instead of Windows - apparently Linux has better drivers for some NICs. Try booting from a Linux "live CD".

Problems are not limited to Windows. Speedtest.net is very flash-heavy, and my 2015 Macbook Pro laptop struggles to reach 250M; I can see the CPU load flatlining at 100% in "Activity Monitor" during the test. But running iperf3 from the command line I can easily fill the available bandwidth (or a gigabit to another local device).

3. It could also be a limitation of the provided router, although if you're using a Talktalk-provided one you'd think they'd give you one that's up to the job. If it provides a way to monitor its CPU utilisation, and it sits at 100% during the test, that would give you a clue.

I have a Mikrotik HeX PoE, and it's relatively under-powered (800MHz single CPU). If you tune it to use its "fasttrack" mode, it can do about 900Mbps of IPv4 - or equivalently, I see ~35% CPU load during a 300Mbps speedtest. Unfortunately there's no fasttrack for IPv6 yet, and with v6 it only handles 250-300Mbps.

Thanks for the suggestions.

My responses.

1. I am referring to data transfer speed. As I am using a supplied modem which I do not have access too, I am unable to see the sync speeds of the line like I could when on FTTC previously. I have searched the internet on this, unless I buy my own capable g.fast router I do not believe I will have access to this info?

2. I have been using my macbook pro (2018) with a USB-C to ethernet adapter, the wifi hub has gigabit ports and my mac tells me that is the speed of which I am connected at when I run my tests

I will see if there is another way to run the tests, it's trying to work out where the bottleneck is. I do not believe it to be a line issue.

3. Led to believe it's capable of reaching such speeds.

You should be able to connect your PC directly to the MT992 modem with an Ethernet cable and establish a PPPoE connection - this will rule out any performance issue with the TT router.

In reply to a post by brookheather:

You should be able to connect your PC directly to the MT992 modem with an Ethernet cable and establish a PPPoE connection - this will rule out any performance issue with the TT router.

I didn't think of that!!! Will try it later, thanks for the suggestion.

There is your problem right there. Seen so many people have issues with those USB to ethernet adapters as they don't work at full speed, i.e. max 24MB per second

In reply to a post by Glovepup:

In reply to a post by brookheather:

You should be able to connect your PC directly to the MT992 modem with an Ethernet cable and establish a PPPoE connection - this will rule out any performance issue with the TT router.

I didn't think of that!!! Will try it later, thanks for the suggestion.

Test completed, 300mb!

In reply to a post by Glovepup:

As I am using a supplied modem which I do not have access too, I am unable to see the sync speeds of the line like I could when on FTTC previously. I have searched the internet on this, unless I buy my own capable g.fast router I do not believe I will have access to this info?

As I said, there's also https://www.dslchecker.bt.com/. Unfortunately, because you're on a TalkTalk line, it probably won't accept your phone number (non-BT). You could try the address checker but I don't think that shows observed speeds.

Therefore, you probably have to take Talktalk's word for it that you are getting a 350M sync speed, unless you buy/borrow another G.fast modem.

Do you have a two-box setup: an Openreach supplied G.fast modem, plus a Talktalk-supplied router?

In reply to a post by Glovepup:

2. I have been using my macbook pro (2018) with a USB-C to ethernet adapter

That's helpful.

Try opening Activity Monitor, then right-click the dock icon and select "Dock Icon > Show CPU History", and see what it does during a speedtest. Note: if you have a dual-CPU machine then you'll likely see four graphs due to hyperthreading. If any two of them go to 100%, then you're CPU-bound.

Also: which USB-C ethernet adapter do you have? Depending on the model, it might be:

* A Thunderbolt to ethernet adapter (best)
* A USB 3.0 or 3.1 ethernet adapter (probably fine)
* A USB 2 ethernet adapter (will limit throughput)

The fact that it's physically a USB-C connector alone doesn't tell you which of these it is.

Just trying with two or three other devices - e.g. desktop PCs, other laptops - can be helpful. If they all flatline at the same throughput then it's unlikely that they are the limiting factor. That would leave your router, the line, and Talktalk's network.

In reply to a post by Glovepup:

3. Led to believe it's capable of reaching such speeds.

If it's a two-box setup then in principle you ought to be able to plug your laptop directly into the modem and configure a PPPoE session. I've done this with VDSL, but not G.fast.

macOS supports it.

You may need to find out your PPPoE username and password to use - ideally extracted from your router's configuration.

I know that some of Talktalk's LLU lines ignore username/password for authentication, using the physical line location instead to authenticate, but don't know about their Openreach footprint. It *might* work with a random username/password. Depends how much you want to experiment

In reply to a post by Glovepup:

Test completed, 300mb!

So it looks like the TT router is limiting your speed - have you checked for any NAT acceleration options (sometimes called CTF) - also make sure you don't have any QoS settings enabled. The router cpu may not be fast enough to handle NAT at your G.fast speeds. Perhaps ask on the TT forums if someone with your router gets the full speed?

You could look at replacing the router with a third party model if you want the full download speed.

Could we worth checking your MTU settings on the TT router. If it negotiates a low MTU during PPP stage, that will limit your throughput too, especially if you are also hitting a CPU (packet per second) limit on the router.

In reply to a post by brookheather:

In reply to a post by Glovepup:

Test completed, 300mb!

So it looks like the TT router is limiting your speed - have you checked for any NAT acceleration options (sometimes called CTF) - also make sure you don't have any QoS settings enabled. The router cpu may not be fast enough to handle NAT at your G.fast speeds. Perhaps ask on the TT forums if someone with your router gets the full speed?

You could look at replacing the router with a third party model if you want the full download speed.

Unfortunately there are not any options to change on the Wifi Hub... think another router might be the best option here.

In reply to a post by chrisdev:

Could we worth checking your MTU settings on the TT router. If it negotiates a low MTU during PPP stage, that will limit your throughput too, especially if you are also hitting a CPU (packet per second) limit on the router.

No MTU setting on it, it's rather simple the Wifi Hub.

In reply to a post by candlerb:

In reply to a post by Glovepup:

As I am using a supplied modem which I do not have access too, I am unable to see the sync speeds of the line like I could when on FTTC previously. I have searched the internet on this, unless I buy my own capable g.fast router I do not believe I will have access to this info?

As I said, there's also https://www.dslchecker.bt.com/. Unfortunately, because you're on a TalkTalk line, it probably won't accept your phone number (non-BT). You could try the address checker but I don't think that shows observed speeds.

Therefore, you probably have to take Talktalk's word for it that you are getting a 350M sync speed, unless you buy/borrow another G.fast modem.

Do you have a two-box setup: an Openreach supplied G.fast modem, plus a Talktalk-supplied router?

In reply to a post by Glovepup:

2. I have been using my macbook pro (2018) with a USB-C to ethernet adapter

That's helpful.

Try opening Activity Monitor, then right-click the dock icon and select "Dock Icon > Show CPU History", and see what it does during a speedtest. Note: if you have a dual-CPU machine then you'll likely see four graphs due to hyperthreading. If any two of them go to 100%, then you're CPU-bound.

Also: which USB-C ethernet adapter do you have? Depending on the model, it might be:

* A Thunderbolt to ethernet adapter (best)
* A USB 3.0 or 3.1 ethernet adapter (probably fine)
* A USB 2 ethernet adapter (will limit throughput)

The fact that it's physically a USB-C connector alone doesn't tell you which of these it is.

Just trying with two or three other devices - e.g. desktop PCs, other laptops - can be helpful. If they all flatline at the same throughput then it's unlikely that they are the limiting factor. That would leave your router, the line, and Talktalk's network.

In reply to a post by Glovepup:

3. Led to believe it's capable of reaching such speeds.

If it's a two-box setup then in principle you ought to be able to plug your laptop directly into the modem and configure a PPPoE session. I've done this with VDSL, but not G.fast.

macOS supports it.

You may need to find out your PPPoE username and password to use - ideally extracted from your router's configuration.

I know that some of Talktalk's LLU lines ignore username/password for authentication, using the physical line location instead to authenticate, but don't know about their Openreach footprint. It *might* work with a random username/password. Depends how much you want to experiment

Wanted to say thanks for your detailed reply, turns out it is the TalkTalk Wifi hub. Connecting directly to the modem improves the speed.

Edited by deleted (Wed 30-Oct-19 20:52:42)

Excellent, just a shame that Talktalk don't supply a router that's up to the job!

Out of interest, how did you get your PPPoE username/password? Did you pick them yourself at ordering time, or does TalkTalk provide them, or did it work with arbitrary values?

In reply to a post by candlerb:

Excellent, just a shame that Talktalk don't supply a router that's up to the job!

Out of interest, how did you get your PPPoE username/password? Did you pick them yourself at ordering time, or does TalkTalk provide them, or did it work with arbitrary values?

It just worked using DHCP on the lan config.

In reply to a post by candlerb:

Excellent, just a shame that Talktalk don't supply a router that's up to the job!

Out of interest, how did you get your PPPoE username/password? Did you pick them yourself at ordering time, or does TalkTalk provide them, or did it work with arbitrary values?

Talktalk residential don't use PPP.

It's IPoE (DCHP) and it will assign an IP to ANY router connected to your landline.