Sender: mgates@ncsa.uiuc.edu
Date: Wed, 02 Jun 1999 12:31:00 -0500
From: Mark Gates <mgates@ncsa.uiuc.edu>
Reply-To: mgates@dast.nlanr.net
Organization: NCSA
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To: Anne Hammond <hammond@solarz.Colorado.EDU>,
"David A. Guevara" <dguevara@mail.arc.nasa.gov>
CC: dast@nlanr.net, hammond@sol.Colorado.EDU
Subject: Re: route from hydra-atm1.colorado.edu -> jsimpson-h.gsfc.nasa.gov
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Hi Anne and David,
I've been investigating the route that you seem to be using. It is very
peculiar to me. Do you know what dates you started having problems
between the machines?
I would say the problem is not congestion but routing. The two things
that looked odd to me are:
1) The RTO router that is listed on both traceroutes. RTO is Los
Angeles, and why your packets would be going through there is a mystery
to me. They should go directly between Chicago (DNG) and Denver (DNJ)
routers.
2) Looking at various round-trip-time and traffic statistics, it seems
there was a definite change in the network on May 20th, 8am UTC. The
round-trip-time between Denver and Chicago-based institutions jumped
from 20ms to 40ms. There doesn't appear to be any traffic going directly
from the Chicago (DNG) router to the Denver (DNJ) router.
I am going to have the NLANR engineering services group look more at
this and hopefully discover and fix whatever routing is broken in the
network. Someone from there may contact you directly if they need more
information. You may still contact me also.
-mark
Anne Hammond wrote:
>
> Hi,
>
> This message below from David Guevara of NASA NREN
>
> Would you be able to help in analyzing this slowdown?
>
> Anne M. Hammond Anne.Hammond@Colorado.EDU
> Network/UNIX Admin 303-492-5578 (FAX -5325)
> JILA / University of Colorado at Boulder
> Boulder, CO 80309-0440
>
> ----- Begin Included Message -----
>
> >From dguevara@mail.arc.nasa.gov Tue Jun 1 08:59:02 1999
> Mime-Version: 1.0
> Content-Type: text/plain; charset="us-ascii"
> Date: Tue, 1 Jun 1999 07:58:54 -0700
> To: "Anne M. Hammond" <hammond@solarz.Colorado.EDU>
> From: "David A. Guevara" <dguevara@mail.arc.nasa.gov>
> Subject: Re: route from hydra-atm1.colorado.edu -> jsimpson-h.gsfc.nasa.gov
> Cc: bill@wizard.nasa.atd.net, mitchell@jila.Colorado.EDU,
> litvanyi@spot.Colorado.EDU, hammond@hydra.colorado.edu,
> brummell@hydra.colorado.edu, dguevara@mail.arc.nasa.gov
> Content-Length: 1929
>
> anne --
>
> the route between hydra-atm1 and jsimpson-h is back up. there seems
> to be a congestion problem. currently our rtt is running about 104ms
> (approximately twice the value we had at the beginning of this project).
> I think the problem lies with vBNS. See below for traceroutes from
> hydra-atm1 and jsimpson-h:
>
> hydra <~>traceroute jsimpson-h.gsfc.nasa.gov
> traceroute to jsimpson-h.gsfc.nasa.gov (169.154.161.43), 30 hops max, 40
> byte pa
> ckets
> 1 198.11.22.25 (198.11.22.25) 1 ms 1 ms 1 ms
> 2 204.131.62.38 (204.131.62.38) 3 ms 3 ms 3 ms
> 3 cs-atm0-0-14.rto.vbns.net (204.147.130.117) 33 ms 33 ms 33 ms
> 4 cs-atm0-0-13.dng.vbns.net (204.147.129.145) 81 ms 204 ms 81 ms
> 5 204.147.128.198 (204.147.128.198) 82 ms 82 ms 83 ms
> 6 gsfc-chi.nren.nasa.gov (198.10.64.49) 97 ms 97 ms 97 ms
> 7 192.12.123.42 (192.12.123.42) 98 ms 98 ms 98 ms
> 8 rtr-900-giga-a.gsfc.nasa.gov (169.154.32.3) 98 ms 98 ms 98 ms
> 9 * jsimpson-h.gsfc.nasa.gov (169.154.161.43) 100 ms 100 ms
>
> jsimpson% /etc/traceroute hydra-atm1.colorado.edu
> traceroute to hydra-atm1.colorado.edu (198.11.22.12), 30 hops max, 96 byte
> packe
> ts
> 1 169.154.161.1 (169.154.161.1) 6.397 ms 7.808 ms 5.467 ms (6.0/6.000)
> 2 rtr-atm-a.gsfc.nasa.gov (169.154.1.1) 8.553 ms 8.924 ms 11.023 ms
> (8.0/9.
> 000)
> 3 192.12.123.41 (192.12.123.41) 9.189 ms 5.739 ms 7.83 ms (7.0/7.000)
> 4 chi-gsfc.nren.nasa.gov (198.10.64.50) 20.339 ms 22.183 ms 22.424 ms
> (22.0
> /21.333)
> 5 204.147.128.197 (204.147.128.197) 21.977 ms 23.711 ms 23.756 ms
> (23.0/22.
> 333)
> 6 cs-atm0-0-12.rto.vbns.net (204.147.129.146) 69.767 ms 72.649 ms
> 69.713 ms
> (69.0/70.000)
> 7 cs-atm0-0-14.dnj.vbns.net (204.147.130.118) 99.653 ms 101.246 ms 105.729
> ms (101.0/101.667)
> 8 204.131.62.37 (204.131.62.37) 103.403 ms 106.348 ms 104.908 ms
> (104.0/104
> .333)
> 9 hydra-atm1.Colorado.EDU (198.11.22.12) 103.892 ms 104.416 ms 107.273
> ms (
> 104.0/104.667)
>
> ----- End Included Message -----
-- Mark Gates 139 ACB NLANR applications support 217-244-7959 http://www.ncsa.uiuc.edu/People/mgates mgates@nlanr.net
----- End Included Message -----