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Anybody could have a hint why my home Wi-fi transfer using nc is so slow?

What I've got:

1) Xubuntu machine with Atheros:

$ lspci | grep -i wireless
03:00.0 Network controller: Qualcomm Atheros AR9285 Wireless Network Adapter (PCI-Express) (rev 0

2) Xubuntu machine with another Atheros:

$ lspci | grep -i wireless
02:00.0 Network controller: Qualcomm Atheros QCA9565 / AR9565 Wireless Network Adapter (rev 01)

3) Wireless Zyxel router "NBG-417N"

How I use that:

Standard nc usage - at one machine I run

cat myfile | nc -l 9999

and on the second one

nc 192.168.x.x 9999 > myfile

I get transfer speeds between 700kBs and 2MBs max. What is weird is that when I download something from Internet, I get easily more than 3MBs! So how come that transferring files locally using nc is slower than downloading something from the Internet?

Thanks!

4
  • What is the size of myfile that you used for testing?
    – Steven
    Oct 13, 2015 at 18:27
  • It's around 300 MB
    – crysman
    Oct 13, 2015 at 18:42
  • Are you saying you can get 3MB/s downloading the internet via wifi?
    – DrZoo
    Oct 13, 2015 at 18:58
  • You've picked pretty much the lowest quality wireless hardware available. Your wireless router was the bottom of the line five years ago. Oct 13, 2015 at 20:01

1 Answer 1

2

OK, folks, Marius seems to be right. I've just made the test via Ethernet over UTP cable. The result is something around 11MBs, so the problem is obviously only in the Wi-fi part (meaning my router's wireless sucks).

Here is the test.

Machine1:

$ cat *mp4 | nc -vl 9999 && du -h *mp4
Listening on [0.0.0.0] (family 0, port 9999)
Connection from [192.168.1.110] port 9999 [tcp/*] accepted (family 2, sport 46455)
339M    test.mp4

Machine 2:

time nc -v 192.168.1.109 9999 > test.mp4
Connection to 192.168.1.109 9999 port [tcp/*] succeeded!

real    0m30.863s
user    0m0.344s
sys 0m6.068s

That is 31 sec transferring 339 MB => 11MBs. Since the router is 100Mbs (12.5MBs), it seems to be OK. No failure in nc.

Cheers and thanks!

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