Extreme Slowness
Adam Rothschild
asr+nanog at latency.net
Fri Oct 27 04:22:51 UTC 2006
Elijah,
On 2006-10-26-16:34:18, Elijah Savage <esavage at digitalrage.org> wrote:
[HTML mail stripped]
> It seems anything traversing level3 has very high latency along with
> what seems overloaded capacity as if they are running in a degraded
> mode I have connections with Time Warner, AT&T, and MCI [...]
On 2006-10-26-16:48:15, Elijah Savage <esavage at digitalrage.org> wrote:
[HTML mail stripped]
> Say like this traceroute. This is from TW to a Broadwing DS3.
>
> 5 tenge-3-2.car1.Cincinnati1.Level3.net (4.78.216.13) 153.267 ms
> 207.125 ms
> tenge-3-1.car1.Cincinnati1.Level3.net (4.78.216.9) 218.920 ms
> 6 ae-5-5.ebr2.Chicago1.Level3.net (4.69.132.206) 36.976 ms 26.923
> ms 57.770 ms
> 7 ge-11-0.core2.Chicago1.Level3.net (4.68.101.37) 254.145 ms
> ge-11-1.core2.Chicago1.Level3.net (4.68.101.101) 258.522 ms
> ge-11-2.core2.Chicago1.Level3.net (4.68.101.165) 227.223 ms
> 8 broadwing-level3-oc12.Chicago1.Level3.net (209.0.225.10) 231.451 ms
> 9 so-1-1-0.c1.gnwd.broadwing.net (216.140.15.1) 53.269 ms 35.568
> ms 22.511 ms
Your postings appear to be missing two key pieces of information which
would help with the community diagnosis requested: source and
destination IP addresses. From the information you did provide, one
can deduce that you're behind a TW/RoadRunner cable modem:
13.216.78.4.IN-ADDR.ARPA domain name pointer tenge-3-2.car1.Cincinnati1.Level3.net
14.216.78.4.IN-ADDR.ARPA domain name pointer ROADRUNNER.car1.Cincinnati1.Level3.net
9.216.78.4.IN-ADDR.ARPA domain name pointer tenge-3-1.car1.Cincinnati1.Level3.net
10.216.78.4.IN-ADDR.ARPA domain name pointer ROADRUNNER.car1.Cincinnati1.Level3.net
Now, the jitter and high latency you're seeing could be a result of
one or more factors, including but not limited to RF/plant issues, TWC
running their transport and/or Level(3) transit hot (which seems to be
a common occurrence these days), ECMP across two circuits of uneven
loading, or your neighbor might be jacking wifi and downloading a
bunch of torrents -- we, the readers, just don't know.
Of note when performing armchair troubleshooting across Level(3)'s
network: the 'ebr's (PTR record of ebr*.{pop}.level3.net == Force10
E1200; Experimental Backbone Router?) tend to drop a lot of diagnostic
traffic (such as, say, 'ping' and 'traceroute') as a part of overly
aggressive control-plane policers. This loss is, of course, strictly
cosmetic, and has no bearing on end-to-end performance. Hence, the
old "to it, not through it" rule applies.
smokeping[1] and iperf[2] (to end hosts) are your friends.
As an aside, I've noticed your string of postings today were all
HTML-tagged. While not expressly forbidden (or even discouraged) by
the current Mailing List AUP, this is generally regarded as bad form;
you might wish to reconfigure your mail client accordingly...
Hope this helps,
-a
[1] <http://oss.oetiker.ch/smokeping/>
[2] <http://dast.nlanr.net/Projects/Iperf/>
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