Now have UFB but FTP downloads are still very slow!

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rlevis

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#124590 13-Jul-2013 02:52

Why is that? I have a dedicated server in the US for a web server and uploading or download files to/from the server using FTP don't go over 311 kB/s (~3Mbps). Speedtests give me 50Mbps download.

As a test, if I open multiple downloads then each one is roughly 300 kbps and I can get some substantial speeds with 10 or 15 files downloading simultaneously. Why can 1 file not go full speed?

Cheers.

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BDFL - Memuneh
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#854738 13-Jul-2013 07:09

Which ISP and I will move it to the correct section if needed.

NonprayingMantis

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#854739 13-Jul-2013 07:10

Why would you epect it to improve?

UFB basically just switches out the copper on the last mile for fibre. All international traffic is basically unaffected since the bottleneck for that traffic was never the last mile copper, except for a few people on very crappy connections.

sbiddle

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#854745 13-Jul-2013 07:43

a) your last mile connectivity whether it's UFB, wireless, fibre or copper will only be as fast as your ISP's backhaul and upstream connectivity.

b) international traffic will always face possible limits due to the way TCP traffic works

Lazarui

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#854902 13-Jul-2013 11:53

rlevis: [SNIP]

As a test, if I open multiple downloads then each one is roughly 300 kbps and I can get some substantial speeds with 10 or 15 files downloading simultaneously. Why can 1 file not go full speed?

Cheers.

hmmm This shows the answer, the FTP server has some limitations imposed on it somehow I'd guess

sampler

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#854946 13-Jul-2013 14:53

Lazarui:
rlevis: [SNIP]

As a test, if I open multiple downloads then each one is roughly 300 kbps and I can get some substantial speeds with 10 or 15 files downloading simultaneously. Why can 1 file not go full speed?

Cheers.

hmmm This shows the answer, the FTP server has some limitations imposed on it somehow I'd guess

I would go with this too. Its rather common, however the way to confirm this is to see if you can download two files at same general ~300 kbps. You could also try a FTP client like filezilla that supports multi file and multi part downloads.

Cheers

Lee

rlevis

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#854957 13-Jul-2013 15:34

It's Microsoft IIS FTP Server 7.0. I'm not aware of any speed limitations per connection.

I'm getting around 8Mbps down and up to a speedtest server near my server in the US.

I didn't know Filezilla supported multi-part downloads. I was just using that a few weeks ago. Generally I manually divide a file into multiple parts using RAR if I want more speed.

freitasm

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#855052 13-Jul-2013 19:47

The type of FTP server doesn't matter. Are you sure the service provider gives it full speed? You say you have 8 Mbps speedtest to a server nearby, and yet have a slow FTP download speed. Perhaps as others are saying that specific server is slow?

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johnr

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#855053 13-Jul-2013 19:53

The confusion around UFB :(

sbiddle

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#855058 13-Jul-2013 20:06

rlevis: It's Microsoft IIS FTP Server 7.0. I'm not aware of any speed limitations per connection.

I'm getting around 8Mbps down and up to a speedtest server near my server in the US.

I didn't know Filezilla supported multi-part downloads. I was just using that a few weeks ago. Generally I manually divide a file into multiple parts using RAR if I want more speed.

Per connection limitations fall into two categories

a) TCP limitations, with 3Mbps being the maximum you can get on a single stream TCP connection from NZ to the West Coast of the US. It doesn't matter of you're on ADSL or a big $$$ per month dedicated CIR fibre connection, the laws of single stream TCP can't be overcome unless you're using TCP window scaling through the entire path.

b) server per connection limitations

As most speedtests use multiple TCP streams there is absolutely no relevence between your speedtest results and your FTP results, except to probably point out your ISP's upstream bandwidth isn't the issue.

Zeon

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#855067 13-Jul-2013 21:05

Sounds definitely like TCP limitations which will be the case even if you spend $9000+ on internet per month. Easiest way is to have multiple streams/connections

Speedtest 2019-10-14

rlevis

347 posts

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#855093 13-Jul-2013 22:17

a) TCP limitations, with 3Mbps being the maximum you can get on a single stream TCP connection from NZ to the West Coast of the US

That's the issue then. It seems to always get to the exact same transfer speed every time. So this 3Mbps per TCP connection is a limitation in the cable to the US?

Talkiet

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#855102 13-Jul-2013 23:00

rlevis:
a) TCP limitations, with 3Mbps being the maximum you can get on a single stream TCP connection from NZ to the West Coast of the US

That's the issue then. It seems to always get to the exact same transfer speed every time. So this 3Mbps per TCP connection is a limitation in the cable to the US?

No, it's a limitation in some (many) TCP/IP implementations.

Cheers - N

Please note all comments are from my own brain and don't necessarily represent the position or opinions of my employer, previous employers, colleagues, friends or pets.

dwl

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#855103 13-Jul-2013 23:05

rlevis:
a) TCP limitations, with 3Mbps being the maximum you can get on a single stream TCP connection from NZ to the West Coast of the US

That's the issue then. It seems to always get to the exact same transfer speed every time. So this 3Mbps per TCP connection is a limitation in the cable to the US?

To clarify, the TCP limitation is primarily client/server settings and capabilities. A 3Mbps limitation is probably not a "cable to the US" limitation but rather the TCP window size being achieved.

A speed of 3Mbps for a single TCP session to the US is consistent with a standard TCP window size of 64kB without window scaling being active and I have seen this same solid speed limit before to the US on older OS. For many years it has been possible to go much faster but this needs to be enabled either by default in later systems or manually in older OS (or maybe not possible if really old).

However, while the above is about the TCP limit, it is also possible the FTP server also has some adverse interactions. There are forum posts about Microsoft IIS FTP Server 7.0 being slow on high latency connections when sourcing from network shares (block size issue) so this type of issue could also be a reason for rate limiting. If you can find another FTP source in a similar location (e.g. Debian mirror) that may help confirm whether client or server issue.

kiwirock

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#855108 13-Jul-2013 23:07

Is this LPFM/StationPlaylist Ross Levis?

The latency between here in the US makes TCP think the capacity must be smaller than it is since it seems a little slowish given the latency to get acknowledgements back from the other end.

Opening more TCP streams helps to work around this since there's more capacity still there, just not less latency.

That's kind of the simplest way to put it.

The worst example and scenario to effect capacity based on latency is satellite Internet.

Cheers,
Gavin Stephens.

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#855113 13-Jul-2013 23:15

Oh dear, your ferrari is on an auckland motorway not the autobahn?

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