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oakserver
Aspiring Expert
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Message 1 of 14

Latency comparison - g.fast vs vdsl

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I would be interested to know how latency compares on a BT G.fast line compared with VDSL, in particular whether the latency differences I experience between my BT and Vodafone lines is due to the service provider or the g.fast vs vdsl technology. 

Pinging www.google.co.uk on my BT g.fast line I get the following result:

  • round-trip min/avg/max/stddev = 7.773/13.524/21.244/4.648 ms

Pinging google from my Vodafone VDSL line I get the follow result:

  • round-trip min/avg/max/stddev = 21.842/24.326/30.325/3.541 ms

It seems that BT G.fast latency is almost half that of Vodafone VDSL.

Would anyone be so good as to ping  www.google.co.uk from a BT VDSL line and post here so I can compare?

PS I should add that my Vodafone VDSL is Fast path (no interleaving) so if possible a comparison with the similar type of connection with no interleaving.

Thanks 😀

 

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13 REPLIES 13
pippincp
Sage
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Message 2 of 14

Re: Latency comparison - g.fast vs vdsl

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There's no point in anyone doing that for you. BT and Vodaphone are 2 different networks, just do a tracert on both and you'll see totally different paths to google.

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oakserver
Aspiring Expert
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Message 3 of 14

Re: Latency comparison - g.fast vs vdsl

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Yes, I did do exactly as you see and no surprise to see two different paths which is why I wanted a ping or trace route will be even better 🙂

Either I didn’t explain what I’m trying to achieve or you completely missed my point. 

I would like to know if a BT VDSL line can match a BT g.fast line in terms of latency and without a BT VDSL line I  have nothing to compare. It would also be good to see how Vodafone's routing affects latency compared with BT routing. I know this isn't a scientific test - but without a BT VDSL line I have nothing to compare at all. 

So there is a little bit of a point to it and hopefully a cooperative individual will be able to help me out (not someone with line problems and  bad latency though!)

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oakserver
Aspiring Expert
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Message 4 of 14

Re: Latency comparison - g.fast vs vdsl

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And from the results so far, if you are interested in latency you can see that Vodafone VDSL compared to BT g.fast latency is almost half. Great for gamers.

You’re welcome.

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bkehoe
Contributor
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Message 5 of 14

Re: Latency comparison - g.fast vs vdsl

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In principle, G.fast will give latency similar to FTTP, the protocol is designed to deliver low latency like this even on poorer lines, and so will always be better than VDSL (especially when potential things like interleaving are considered). Mine dropped from the high teens/low 20 region with VDSL on a short (under 150m line) to the 9/10ms region with G.fast to London. I only saved line stats of when I had VDSL, nothing with pings though.

Unless its in the same location and same service provider to the same physical server (not google.co.uk where two different people could be routed to 2 different data centres) then a comparison like you're asking for here is very hard to form. EG A FTTP user in Scotland/NI will have approx 15ms to London. Even yours is approx 1ms less than mine so I presume you're further south than Manchester. 😉
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oakserver
Aspiring Expert
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Message 6 of 14

Re: Latency comparison - g.fast vs vdsl

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Thanks for your reply

I can see what you mean that your proximity to the servers and the routes to those servers will make a substantial difference.

Im in the South East, close to London.

So let’s get down to facts - the latency on my BT G.fast line in my area is almost half that of my vodafone VDSL line at least to the destination I was pinging. It would be better to pick a server that is know to be fed from only one data centre to rule out responses from different locations.

So I think I’ve narrowed it down a little to get the best results. Anyone connected to Cabinet 9 in my area willing to give me an indicator of ping to any up address of your choosing to be honest as long as I can ping the same. Trace route even better to be sure we are taking the same routes 🙂 

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iniltous
Guru
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Message 7 of 14

Re: Latency comparison - g.fast vs vdsl

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What is that you are trying to establish , that Gfast has better latency than VDSL , or that your VF VDSL should perform better and you are going to try and convince VF that your VDSL should have better latency and be the same as Gfast ?, if you have both why does it matter, if you have both  , just use Gfast .

I get that some may want to optimise their broadband and probably know more about the system than the customer service reps of the retail company that supply it , but ultimately it’s a domestic service , that the user pays a domestic rate for...personally I think sometimes the consumer is expecting far too much from a service that is aimed at people who just want plug and play...if you want an ISP that will endlessly tweak , whatever they can tweak to try and squeeze whatever you want from the ‘system’ then using a mass market ISP isn’t likely to provide what you want.

Stu_H
Aspiring Expert
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Message 8 of 14

Re: Latency comparison - g.fast vs vdsl

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Are you testing latency under load?

it’s all nice when you look at a quiet network but I would try saturating your connection and then see how it’s performing. 

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oakserver
Aspiring Expert
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Message 9 of 14

Re: Latency comparison - g.fast vs vdsl

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Goodness me, is it really so difficult. I don’t have to explain to you why it matters to me but it does otherwise  I wouldn’t be asking the damn question! 

OK so my g.fast line drops two or three times a day. This is a pain in the **bleep** when you are in the middle of a teams call at work. The Vodafone line is completely stable. 

I don’t want to pay for an unstable G.fast line, but my sons appreciate the low latency  for the gaming pc and Xbox. 

So, how do I decide whether to keep the gfast line or downgrade it to VDSL which brings slightly better stability. If the BT VDSL is going to be worse than the Vodafone line then cancel my BT services completely?

Without some figures I can’t tell if it is worth recontracting with BT for a VDSL line for a further 2 years.

Can anyone tell me how best to determine this if it’s not asking for someone to help me compare?

 

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oakserver
Aspiring Expert
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Message 10 of 14

Re: Latency comparison - g.fast vs vdsl

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I’ve tried both.

@bkehoe has explained though the location and route is probably the biggest factor at play here so hard to compare like for like unless I had two BT lines in my home!
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