I have sent an email to through the online customer site, but I was wondering if anyone here had some ideas while I wait for them to get back to me.

It seems that there is a per TCP connection speed limit on Cable. I have a box at Linode in London and when transferring files via SSH the rate is slow ~200kB/s. First I thought it was just a slow route, but if I start two SSH session, running in side by side, I can have two parallel downloads each running at the ~200kB/s speed, so they are summing to something nearer ~400kB/s. Why can't I get ~400kB/s in the one connection when I can pull that cumulatively over two separate SSH sessions?

I can demo this as Linode has a speed test page that give you a file download https://www.linode.com/speedtest/

Using wget I can get http://speedtest.london.linode.com/100MB-london.bin in 9m 13s the file is 104857600B so average is 185kB/s

Then using wget in two separate terminals in parallel (I added ?1 and ?2 to the end of each URL so it didn't come from the transparent proxy) and I got 9m 44s for 175kB/s and 9m 45s for 175kB/s. If it was a bandwidth constrained connection I would have expected something like 19m 30s to complete the 200MB, but that is not the case.

Trying some of the other Linode speed test files I get the same results for Japan and Fremont. The speed is different but there seems to be a per connection limit and running in parallel doesn't seem to affect other download.

This isn't an issue at the Linode end as I pull the same file down to a box in the US 1m 40s 1MB/s so the Linode end can spit the content out fast enough on its speed test files.

So is there a per connection limit? Is there anyway to work around this so I can just have the one connection operating at full speed?

Thanks

Traceroute for completeness
<snip>:~$ traceroute speedtest.london.linode.com
traceroute to speedtest.london.linode.com (176.58.107.39), 30 hops max, 60 byte packets
 1  <snip>  0.591 ms  0.579 ms  0.725 ms
 2  * * *
 3  lo0.internet.ivpn.pe25.telstraclear.net (218.101.61.124)  67.656 ms  67.729 ms  67.711 ms
 4  ie2-g-0-0-0.telstraclear.net (203.98.50.2)  68.069 ms  68.070 ms  68.066 ms
 5  * * *
 6  unknown.telstraglobal.net (134.159.174.37)  68.177 ms  65.703 ms  65.807 ms
 7  i-0-0-4-0.tlot-core01.bx.telstraglobal.net (202.84.142.118)  156.907 ms  242.681 ms  243.022 ms
 8  i-0-0-0-3.eqla01.bi.telstraglobal.net (202.40.149.134)  242.474 ms  241.824 ms  241.969 ms
 9  63-218-51-149.static.pccwglobal.net (63.218.51.149)  283.869 ms  283.768 ms  283.598 ms
10  telecity.ge9-9.br02.ldn01.pccwbtn.net (63.218.13.222)  438.956 ms  394.823 ms  422.172 ms
11  212.111.33.238 (212.111.33.238)  422.297 ms  422.202 ms  422.249 ms
12  speedtest.london.linode.com (176.58.107.39)  421.653 ms  411.505 ms  411.487 ms