I don’t know what the issue is here…
Here’s my setup.
I have a reasonably fast Desktop PC sitting on three T1’s (twisted into a single line? or however they are joined) which normally gives us about 4Mbps up and down. The desktop has a static IP, and we’re currently hosting it in midtown Manhattan.
We just built a dedicated server box at a hosting company in Brooklyn, which comprises of a much faster machine sitting on a 10Mbps unmetered and reportedly unthrottled line (has a dedicated IP as well). The server is running Windows Server 2008.
So on one side of the equation I should have 4Mbps up, and on the other I should have 10Mbps down, yet when I transfer a large file (2Gb) I’m getting speeds around 200Kbps!! Wtf?!?
Here is a traceroute from here to there:
traceroute to 66.109.xxx.xxx (66.109.xxx.xxx), 64 hops max, 52 byte packets 1 66.9.31.1 (66.9.31.1) 1.459 ms 0.744 ms 0.670 ms 2 66.9.212.18 (66.9.212.18) 44.353 ms 15.398 ms 11.758 ms 3 ip-160-79-127-229.autorev.intellispace.net (160.79.127.229) 14.341 ms 10.849 ms 8.220 ms 4 gigabitethernet6-24.ar4.nyc1.gblx.net (207.136.166.53) 7.620 ms 33.029 ms 33.442 ms 5 64.209.99.6 (64.209.99.6) 23.604 ms 31.267 ms 19.221 ms 6 galaxy-visions.nyc2.webair.net (69.42.90.156) 6.183 ms 4.622 ms 13.551 ms 7 *^C(Step 7 is my server, as the traceroute is blocked by the firewall).
I’ve ran speedtests on both machines (speedtest.net) and the numbers roughly match what I should be getting (what I listed earlier).
The strange thing is that when I start my transfer of a 2Gb file, the transfer speeds for the first 1Mb are around 1Mbps, then it falls steadily after that until it flattens out at anywhere between 200-300kbps. I don’t understand why I’m getting such slow speeds from these two very high speed connections!!
Any thoughts?
Answer
This is by no means a complete answer, but what is the MTU on the packets, and does the switching/routing equipment in between support that MTU if it’s not of a standard size (for example jumboframes).
Also, can you see if packets are being dropped?
Are there other machines at each end you can do a similar testing with to try and rule out the problem being one of the hosts themselves?
Finally, if you do a speed test between each end point, and a third-party node, do you find anything interesting?
If you do some ping tests (set the no-fragment flag, and try various packet sizes), it may help to have tcpdump/wireshark running – so you can see any messages being sent back from intermediate routers which may tell you why the connection speed slows down to a grind.
Attribution
Source : Link , Question Author : neezer , Answer Author : Xerxes
