nanog mailing list archives

Re: level3.net in Chicago - high packet loss?!?


From: Joe Maimon <jmaimon () ttec com>
Date: Tue, 06 Sep 2005 10:35:03 -0400


If the hop(s) following the one you see loss for shows no loss, then disregard the loss for that hop, obviously whatever it is, it does not affect transit, which is what you really want to know.

Is that correct?


Network Fortius wrote:

And how exactly would you interpret the number returned by net_loss (int), in a column called "LOSS", in reference to reachability of a "hop" between two end points:

int net_loss(int at)
{
  if ((host[at].xmit - host[at].transit) == 0)
    return 0;
  /* times extra 1000 */
return 1000*(100 - (100.0 * host[at].returned / (host[at].xmit - host[at].transit)) );
} ?

Thanks,
Stef
Network Fortius, LLC


On Sep 6, 2005, at 7:45 AM, Robert E.Seastrom wrote:


Network Fortius <netfortius () gmail com> writes:


Anybody having any idea why such a high packet loss on lever3's
network, in Chicago?


End-user misinterpreting output from MTR.  This network does not
appear to have any packet loss end-to-end.

                                        ---Rob



Stef:~ scm$ mtr -r www.yahoo.com
...
tbr1-p010802.cgcil.ip.att.net             0%    16   16   15.12
24.21   49.26
ggr2-p310.cgcil.ip.att.net                0%    16   16   13.18
42.66  118.99
so-1-1-0.edge1.chicago1.level3.net        0%    16   16   14.48
35.84  126.48
so-2-1-0.bbr1.chicago1.level3.net        63%     6   16   14.44
43.74   79.97
^^^^^^^
as-1-0.bbr2.sanjose1.level3.net           0%    16   16   61.95
80.64  176.01
ge-10-2.ipcolo3.sanjose1.level3.net       0%    16   16   63.37
95.61  148.46
unknown.level3.net                        0%    16   16   63.34
86.46  168.62
unknown-66-218-82-217.yahoo.com           0%    16   16   62.09
88.91  127.58
p4.www.scd.yahoo.com                      0%    16   16   64.51
89.96  183.79

TIA,
Stef
Network Fortius, LLC






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