Packet loss, any advice?

jsteel · 2012-08-02 22:16:01

Hi,

I'm in the UK with the ISP Virgin using fibre optic broadband. I've been with them for about two years and I've had problems on and off with packet loss (giving a slow/intermittent connection). I don't want to leave them as it's nice not having to pay for a land line (for ADSL broadband) and I like their TV service. Also 70%+ of the time it's fine. I've complained a number of times and they are happy to give a small refund and send an engineer out but the problem never gets fixed for good.

When I notice the Internet being slow/intermittent I run a ping and notice around a 5% to 20% packet loss on both wired and wireless connections. It's not just a problem with Arch, as friends come over with other operating systems and notice the same problem when it's occurring.

uzbl barely works when there's a problem but other browsers manage to cope a little better. I wonder why that is, and it's a shame that I can't use what looks like a nice browser to hack. Generally when I hit refresh once or twice the page loads quickly (apart from in uzbl) and when running a speed test I'm getting 20mb/s.

Has anyone got any advice to cope with packet loss? Can Arch or a web browser be told to "try harder" when reaching out? I know, I'm clutching at straws here.

Thanks

brebs · 2012-08-02 22:50:27

I suppose these could help:

/proc/sys/net/ipv4/tcp_retries1
How many times to retry before deciding that something is wrong and it is necessary to report this suspicion to network layer. Minimal RFC value is 3, it is default, which corresponds to 3sec-8min depending on RTO.
/proc/sys/net/ipv4/tcp_retries2
How may times to retry before killing alive TCP connection. RFC 1122 says that the limit should be longer than 100 sec. It is too small number. Default value 15 corresponds to 13-30min depending on RTO.

bernarcher · 2012-08-02 22:54:31

Moving to Networking, Server, and Protection.

fukawi2 · 2012-08-02 23:51:25

Where is the loss? Use `mtr` to see the loss at each hop. If it's past any of your equipment (ie, on the ISP end of the fibre) then probably not a whole lot you can do.

jsteel · 2012-08-03 08:47:59

Thanks brebs, I'll have a play with that.

The connection is OK today, but I tried using mtr on a few sites and the bbc.co.uk website showed some loss (others did not):

mtr -rc5 bbc.co.uk
HOST: netbook                     Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- 10.151.228.1               0.0%     5   25.7  13.5   8.1  25.7   7.4
  2.|-- winn-core-1a-ae4-601.netw  0.0%     5   26.2  13.5   9.2  26.2   7.2
  3.|-- winn-bb-1a-so-130-0.netwo  0.0%     5   34.7  24.4   8.5  59.7  22.6
  4.|-- brnt-bb-1b-as5-0.network.  0.0%     5    9.8  10.3   9.8  10.9   0.5
  5.|-- brnt-bb-1a-ae0-0.network.  0.0%     5   12.4  16.4   9.8  27.9   7.8
  6.|-- glfd-bb-1b-as1-0.network.  0.0%     5   17.1  17.4  16.9  19.2   1.0
  7.|-- glfd-tmr-1-ae5-0.network.  0.0%     5   20.2  22.4  18.0  35.3   7.3
  8.|-- tcl5-ic-1-as0-0.network.v  0.0%     5   18.3  34.7  18.3  79.6  26.3
  9.|-- 212.58.239.249            20.0%     5   22.3  21.1  19.1  22.4   1.5
 10.|-- ???                       100.0     5    0.0   0.0   0.0   0.0   0.0
 11.|-- ae1.er01.rbsov.bbc.co.uk   0.0%     5   39.4  32.1  20.7  51.1  12.8
 12.|-- 132.185.255.60             0.0%     5   18.8  28.8  18.8  42.4  10.3
 13.|-- 212.58.241.131             0.0%     5   18.9  33.3  18.9  39.6   8.9

I'm not sure what that means exactly; I can navigate to the site without any issues right now.

Thanks

jsteel · 2012-08-03 18:45:34

A few more:

mtr -rc5 bbs.archlinux.org
HOST: netbook                     Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- 10.151.228.1               0.0%     5   23.5  23.5   8.4  37.1  13.3
  2.|-- winn-core-1a-ae4-601.netw  0.0%     5   29.1  16.3  11.2  29.1   7.3
  3.|-- winn-bb-1a-so-130-0.netwo  0.0%     5   56.8  30.2   8.1  56.8  19.7
  4.|-- popl-bb-1b-as5-0.network.  0.0%     5   27.7  17.5  12.0  27.7   6.6
  5.|-- nrth-bb-1a-as1-0.network.  0.0%     5   21.7  23.4  16.6  33.9   6.5
  6.|-- nrth-tmr-1-ae1-0.network.  0.0%     5   70.4  46.0  18.1  95.5  35.1
  7.|-- fran-ic-1-as0-0.network.v 20.0%     5   86.0  46.8  31.9  86.0  26.3
  8.|-- decix-gw.hetzner.de       40.0%     5   71.8  53.9  43.6  71.8  15.6
  9.|-- 213.239.240.252            0.0%     5   44.4  59.6  42.3  79.6  16.5
 10.|-- hos-tr3.ex3k3.rz12.hetzne  0.0%     5   41.3  51.0  41.3  61.5   7.4
 11.|-- alderaan.archlinux.org     0.0%     5   37.3  44.8  37.3  56.2   7.4

mtr -rc5 archlinux.org
HOST: netbook                     Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- 10.151.228.1              40.0%     5    8.3   9.8   8.3  11.0   1.4
  2.|-- winn-core-1a-ae4-601.netw  0.0%     5   24.2  23.6  13.7  32.4   7.5
  3.|-- winn-bb-1a-so-130-0.netwo  0.0%     5   24.7  19.0  10.2  24.7   7.2
  4.|-- brnt-bb-1b-as5-0.network.  0.0%     5   12.0  21.6  10.5  37.2  13.7
  5.|-- brnt-tmr-1-ae5-0.network.  0.0%     5   13.0  23.6  12.1  59.4  20.3
  6.|-- telc-ic-1-as0-0.network.v 20.0%     5   29.3  18.1  11.7  29.3   8.3
  7.|-- te1-3.ccr01.lon04.atlas.c  0.0%     5   20.5  19.8  16.2  21.6   2.1
  8.|-- te0-4-0-4.ccr21.lon01.atl  0.0%     5  122.7 103.6  95.1 122.7  11.2
  9.|-- te0-2-0-4.mpd21.lon13.atl 20.0%     5   95.0  94.3  93.4  95.0   0.7
 10.|-- te0-3-0-4.ccr21.bos01.atl  0.0%     5   94.6  97.6  94.6 102.5   3.2
 11.|-- te3-1.ccr01.orh01.atlas.c  0.0%     5   95.3 167.2  93.5 276.2  83.0
 12.|-- te9-8.ccr01.alb02.atlas.c  0.0%     5   94.5 139.6  94.5 212.2  51.8
 13.|-- te8-7.ccr01.buf02.atlas.c 20.0%     5  100.9 175.4 100.9 273.3  87.7
 14.|-- te7-8.ccr02.cle04.atlas.c 60.0%     5  106.3 117.7 106.3 129.1  16.1
 15.|-- te7-8.ccr01.pit02.atlas.c 60.0%     5  109.4 172.9 109.4 236.4  89.8
 16.|-- 38.104.120.102             0.0%     5  118.0 115.8 114.6 118.0   1.4
 17.|-- cust02-ge-0-0.eri.velocit 60.0%     5  128.8 125.4 122.0 128.8   4.8
 18.|-- gudrun.archlinux.org      40.0%     5  115.6 115.2 114.3 115.7   0.8

fukawi2 · 2012-08-05 23:17:49

That's not hugely unusual... Busy routers will often treat your traceroute (aka mtr) traffic with a much lower priority than actual web traffic etc, so while you see the packet loss in your traceroute, there actually isn't packet loss when you view the website. It's just a busy router making a choice to handle the "more" important web traffic over your "less" important ICMP packets.

You'll really have to do the trace when you're having the problems.

I would be concerned about the first hop in the last trace you posted:

 1.|-- 10.151.228.1              40.0%     5    8.3   9.8   8.3  11.0   1.4

40% packet loss will cause you problems, and the first hop is usually under your control. What is 10.151.228.1? Your router? Or does the fibre act as a bridge so that's actually your ISP's router? (I'm not familiar with UK connectivity "standards")

Last edited by fukawi2 (2012-08-05 23:18:11)

jsteel · 2012-08-09 13:06:53

The last post was when I was having issues. I do not know what that IP is, my router uses 192.168.0.1.

The connection has been fine since I last posted (even on computers without any "tcp_retries" tweaking). I'll have to wait again for the issue to return to further test this... but I hope it doesn't!

Thanks for the help.

Arch Linux

#1 2012-08-02 22:16:01

Packet loss, any advice?

#2 2012-08-02 22:50:27

Re: Packet loss, any advice?

#3 2012-08-02 22:54:31

Re: Packet loss, any advice?

#4 2012-08-02 23:51:25

Re: Packet loss, any advice?

#5 2012-08-03 08:47:59

Re: Packet loss, any advice?

#6 2012-08-03 18:45:34

Re: Packet loss, any advice?

#7 2012-08-05 23:17:49

Re: Packet loss, any advice?

#8 2012-08-09 13:06:53

Re: Packet loss, any advice?

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