Re: [gentoo-user] {OT} Cable latency & Skype

[Mick <michaelkintzios@gmail.com>]

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On Tuesday 13 November 2007, Mark Shields wrote:
> On Nov 12, 2007 6:59 PM, Grant <emailgrant@gmail.com> wrote:
> > I just switched from DSL to cable and I'm noticing a significant delay
> > when using Skype, even when nothing else is happening on my network.
> > Has anyone else noticed this and had success "fixing" it?  I'm using a
> > Gentoo router so I can try just about anything.
> >
> > - Grant
> > --
> > gentoo-user@gentoo.org mailing list
>
> I work for as a cable modem technician.  The first thing to check for when
> you're having cable internet problems is the modem.  Call up tech support
> and ask them to check the signals on the modem (upstream power, downstream
> rcv, downstream SNR, upstream SNR, headend receive) and make sure they're
> in range.  Also ask them to ping and (if available) rf ping to check for
> latency/packet loss.  Also ask them to check the circuits/backbone.  Also,
> can you reproduce this latency in the form of a ping/traceroute?  This will
> go a long way with ISPs in determining where the problem is (although
> Comcast just blows off high latency on pings as the result of dropping them
> due to lower priority).

Interesting to hear this.  The OP will no doubt have a different traceroute to 
show the ISP, but does the comment on dropping pings explain the % loss shown 
below in certain hops, or is it just a matter of overloaded switches?
==========================================================================
HOST: lappy                       Loss%   Snt   Last   Avg  Best  Wrst StDev
  5. 217.41.177.66                 0.0%    15   17.9  18.0  15.7  22.8   1.7
  6. 217.41.177.134                6.7%    15   21.0  17.5  15.7  21.0   1.5
  7. 217.41.177.54                 0.0%    15   17.0  16.6  15.1  20.7   1.4
  8. 217.47.166.106                0.0%    15   16.0  16.9  15.3  18.9   1.1
  9. core1-pos5-2.faraday.ukcore.  0.0%    15   17.0  45.3  15.2 192.3  52.7
 10. core1-pos0-15-0-10.ilford.uk  0.0%    15   18.9  18.3  17.1  19.5   0.7
 11. 194.74.77.222                 0.0%    15   18.1  17.1  15.5  19.1   1.0
 12. t2c1-ge14-0-0.uk-ilf.eu.bt.n  6.7%    15   17.9  17.3  15.7  19.1   0.9
 13. t2c1-p4-0-0.us-nyc.eu.bt.net  0.0%    15  107.3 108.1 106.1 109.7   1.1
 14. 12.116.102.17                 0.0%    15  108.3 107.9 105.5 110.0   1.3
 15. tbr1.n54ny.ip.att.net         0.0%    15  133.2 133.8 131.2 135.4   1.4
 16. cr2.n54ny.ip.att.net          0.0%    15  135.2 133.5 131.6 135.7   1.3
 17. cr2.wswdc.ip.att.net          0.0%    15  132.2 132.9 131.3 134.7   1.1
 18. cr1.attga.ip.att.net          0.0%    15  134.2 133.6 132.1 135.7   1.2
 19. tbr2.attga.ip.att.net         0.0%    15  135.2 134.0 132.0 136.2   1.3
 20. gar4.attga.ip.att.net         0.0%    15  132.2 134.1 130.0 159.4   7.1
 21. 12.124.64.62                 20.0%    15  140.2 138.6 137.0 140.4   1.1
 22. te-9-1-ur01.south.tn.knox.co  6.7%    15  141.2 140.4 138.1 141.5   1.0
 23. te-8-3-ur02.west.tn.knox.com  0.0%    15  141.2 140.3 139.1 141.2   0.6
 24. ge-1-46-ur01.west.tn.knox.co  0.0%    15  138.2 138.6 137.8 140.6   0.9
==========================================================================

Note some of these are being dropped in the UK, rather than by Comcast.
-- 
Regards,
Mick

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