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Standard User LakesGeek
(newbie) Mon 30-Sep-13 18:25:08
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Does uploading still bring your connection to its knees?


[link to this post]
 
I know this was always a problem with ADSL. I'm just curious whether it has the same effect on VDSL/FTTC.

Whenever you upload something on ADSL, if you don't have some kind of throttling software in place on your machine, it'll saturate the upload bandwidth and this also saturates the entire connection so your ping times go through the roof and downloads go down to dial-up speeds. Routers with QoS can alleviate it somewhat, but it doesn't seem to help completely.

Just wondering if FTTC will be more of the same, or if it's more intelligent.
Standard User David_W
(fountain of knowledge) Mon 30-Sep-13 18:40:38
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Re: Does uploading still bring your connection to its knees?


[re: LakesGeek] [link to this post]
 
I don't have any problems with upstream saturation on FTTC.

However, I have the full 20Mbit/s sync speed on the 80/20 tier (at roughly 96.8% usable bandwidth, that equates to 19.36Mbit/s) and a router running pfSense with the (upstream) traffic shaper in use to prioritise the transmission of upstream data into several priority tiers - off the top of my head, latency sensitive data (including VoIP and NTP) is prioritised over TCP ACKs, which are prioritised over SSH traffic (so as to preserve interactivity), which is prioritised over everything else.

Ultimately, it's difficult to saturate a 20Mbit/s upstream other than when running speed tests. When we use our upstream heavily, it's uploading data to Dropbox, which typically accepts data no faster than 6Mbit/s.


How your traffic is fitted into the available upstream behaviour is entirely under the control of your equipment. How sophisticated a setup you need is a function of how little upstream bandwidth you have (the slower the connection, the easier it is to drive to saturation), how heavy an upstream user you are, and how much you care about latency and interactive performance.

Standard User MHC
(sensei) Mon 30-Sep-13 19:40:03
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Re: Does uploading still bring your connection to its knees?


[re: LakesGeek] [link to this post]
 
In reply to a post by LakesGeek:
I know this was always a problem with ADSL. I'm just curious whether it has the same effect on VDSL/FTTC.

Whenever you upload something on ADSL, if you don't have some kind of throttling software in place on your machine, it'll saturate the upload bandwidth and this also saturates the entire connection so your ping times go through the roof and downloads go down to dial-up speeds. Routers with QoS can alleviate it somewhat, but it doesn't seem to help completely.

Just wondering if FTTC will be more of the same, or if it's more intelligent.



I have never come across that. On my ADSL connection it was quite possible to have a full speed upload running along with a download at te same time - teh only affect they had on each other was te need for ACKs to be transmitted and received.

Your Ping times will go through the roof because they are low priority and you have instructed your connection to run higher priority functions.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C


taurus excreta cerebrum vincit


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Standard User Chrysalis
(legend) Mon 30-Sep-13 20:10:23
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Re: Does uploading still bring your connection to its knees?


[re: LakesGeek] [link to this post]
 
first its harder to saturate upload now, second no. As fatter pipes have less saturation affect when full.

BT Infinity 2 Since Dec 2012 - BQM
Standard User LakesGeek
(newbie) Mon 30-Sep-13 20:30:55
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Re: Does uploading still bring your connection to its knees?


[re: LakesGeek] [link to this post]
 
Thanks all, sounds promising.

*Resume looking forward to FTTC that could be here any time between next week and the end of the year*
Standard User ukhardy07
(fountain of knowledge) Mon 30-Sep-13 20:54:28
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Re: Does uploading still bring your connection to its knees?


[re: MHC] [link to this post]
 
On ADSL 2+ it's easy to saturate the upload, a lot of ISPs - BT (in my experience) and PlusNet 100% seem to have a management system in place to stop this having such a big affect. Also some routers have QOS or something similar - so that's why you have likely not experienced this.

On fibre it's near enough impossible in standard usage for this to occur however.
Standard User MHC
(sensei) Mon 30-Sep-13 21:08:17
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Re: Does uploading still bring your connection to its knees?


[re: ukhardy07] [link to this post]
 
Yes, it is possible to saturate the upload, but in doing so does not, as the OP states, saturate the download.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C


taurus excreta cerebrum vincit
Standard User mattewan
(regular) Mon 30-Sep-13 22:27:39
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Re: Does uploading still bring your connection to its knees?


[re: LakesGeek] [link to this post]
 
Generally speaking, the more bandwidth you have, the harder it is to saturate.

Think of it like taps in a house. If there are small pipes in the house, and you turn a tap on in your sink, then turn another tap on in your bath, there is a noticeable loss of throughput to the sink tap.

If you had bigger pipes, you probably wouldn't notice any reduced flow, even if the pipes were at 100% because a new tap uses a smaller fraction of the capacity overall than it would on a smaller pipe.

Obviously, if you are completely battering a large connection, then eventually it will become saturated.

Standard User LakesGeek
(newbie) Tue 01-Oct-13 00:37:42
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Re: Does uploading still bring your connection to its knees?


[re: mattewan] [link to this post]
 
I see.. I think.. I'd have thought as long as the remote server is just as fast as yours then it'll max out either way and just take all the bandwidth it can, whether it's 0.5Mbps, 20Mbps or 20000Mbps, and so other things will always be struggling.

The thing with ADSL seemed to be that somehow uploading was more "damaging" to the connection, such that games would lag out, websites would take ages to load etc. Whilst maxing out the download rate didn't really do anything. Never completely understood why, but thought it was something to do with the asynchronous nature of the technology. That uploading is kind of... "more difficult", for lack of a less ridiculous way to put it.
Standard User LakesGeek
(newbie) Tue 01-Oct-13 00:41:53
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Re: Does uploading still bring your connection to its knees?


[re: MHC] [link to this post]
 
I'm not sure if it saturates the download per se, I think it's something like - as someone else stated - it struggles to get ACK packets through and so has that effect. I could never seem to get it to work properly, even with QoS on and ACK prioritisation enabled on a Draytek router.

Sounds promising though.

It may be difficult to saturate in "normal usage", but that goes for ADSL as well. It's more "abnormal usage" that causes problems, like uploading HD videos to Youtube for example, which I can't really do on ADSL unless it's overnight as it'd cripple the (shared) internet connection for 2-3 hours.
The advantage is that that would be reduced to minutes rather than hours, but I find that data usage tends to adapt to what's available - we'll end up with higher definition camera technology, things like that, and back to 2-3 hour uploads again after a handful of years. Guess I'm thinking ahead.

Edited by LakesGeek (Tue 01-Oct-13 00:46:55)

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