[outages] Comcast<->AT&T packet loss (possibly within CA)

Michael Smith mksmith at mac.com
Sat Mar 8 21:27:15 EST 2014


A couple of things

- Hop 8's IP is an AT&T so likely an interface on an AT&T router, since you're headed towards it in your traceroute (next_hop).
- Have you tried something like hping that will allow you to use TCP for your test?
- Have you contacted InterNAP and told them to open a ticket with AT&T to open a ticket with AT&T using the data you have?  

Mike


On Mar 8, 2014, at 4:53 PM, Jeremy Chadwick <jdc at koitsu.org> wrote:

> Since roughly Friday, I've been seeing what appears to be packet loss
> somewhere within Comcast/AT&T network mesh.  Source and destination IPs
> are provided below as well, ditto with some mtrs from src->dst and
> dst->src.  I keep periodic mtrs (both directions) going all the way back
> to 03/04.  I can make all of those logs available if asked.
> 
> The issue started on 03/07 @ 21:33 PST suddenly -- not a "gradual"
> increase -- and lasted until an undetermined time (very hard to tell
> from mtrs) but I'd estimate ~02:00 PST on 03/08 (today).
> 
> The issue then appeared to start back up again ~07:00 PST, though it's
> hard to give an exact time (seems sort of a gradual increase, thus hard
> to pinpoint).  It's been ongoing since.
> 
> The loss varies from 3% to 20%, but you can definitely "feel" it across
> an SSH session, so it's not ICMP prio.
> 
> I will make myself clear: it's very hard to "show" someone the way this
> problem manifests itself, because the packet loss will vary all over the
> place between different hops.  It *definitely* starts at a particular
> point and "trickles down", but due to the fact that the loss is a
> smaller percentage, there are times where a hop will suddenly show 0%.
> TL;DR -- You'd really have to see a longer log (say, an hour's worth) to
> be able to say "ah yes, this really is a problem" and not blow it off as
> ICMP prio.
> 
> And as usual, there's one of those "mystery routers" (hop #8 in the
> first example) that peering providers looooooove to use as a scapegoat
> when it comes to shifting blame, ex. provider A says "that's a device
> owned by provider B", provider B says "that device is provider A's
> responsibility", and neither side does anything about the issue.
> However I should note that the "mystery router" usually does show some
> degree of loss even when this issue isn't occurring (likely ICMP prio on
> the device), but that makes it even more difficult to determine where
> the issue begins.
> 
> 
> src IP: 76.102.14.35   (Comcast; Mountain View, CA)
> dst IP: 204.109.61.174 (RootBSD; Dallas, TX)
> 
> === Sat Mar  8 16:22:00 PST 2014  (1394324520)
> Start: Sat Mar  8 16:22:00 2014
> HOST: icarus.home.lan                                                 Loss%   Snt   Rcv  Last   Avg  Best  Wrst
>  1.|-- gw.home.lan (192.168.1.1)                                        0.0%    30    30   0.4   0.3   0.2   0.4
>  2.|-- 76.102.12.1                                                      0.0%    30    30   8.0   8.8   8.0  12.2
>  3.|-- te-0-2-0-5-ur06.santaclara.ca.sfba.comcast.net (68.86.249.253)   0.0%    30    30   8.2   9.0   8.2  16.5
>  4.|-- te-1-1-0-1-ar01.oakland.ca.sfba.comcast.net (69.139.198.94)      0.0%    30    30  11.9  12.2  10.1  15.0
>  5.|-- be-90-ar01.sfsutro.ca.sfba.comcast.net (68.85.155.14)            0.0%    30    30  12.0  12.5  10.1  15.1
>  6.|-- he-3-8-0-0-cr01.sanjose.ca.ibone.comcast.net (68.86.94.85)       0.0%    30    30  13.0  14.0  11.8  18.0
>  7.|-- pos-0-3-0-0-pe01.11greatoaks.ca.ibone.comcast.net (68.86.87.18)  0.0%    30    30  15.6  17.2  15.3  19.8
>  8.|-- 192.205.37.1                                                    70.0%    30     9  54.8  67.7  53.6 102.2
>  9.|-- cr2.sffca.ip.att.net (12.122.86.202)                            13.3%    30    26  65.2  63.5  61.0  65.7
> 10.|-- cr2.la2ca.ip.att.net (12.122.31.133)                             6.7%    30    28  63.3  63.5  60.9  75.2
> 11.|-- cr2.dlstx.ip.att.net (12.122.28.177)                             3.3%    30    29  65.2  63.7  61.1  69.7
> 12.|-- ggr6.dlstx.ip.att.net (12.122.138.113)                           6.7%    30    28  60.3  64.5  59.9 153.6
> 13.|-- 12.90.228.14                                                     6.7%    30    28  60.3  60.7  60.2  62.5
> 14.|-- border1.pc1-bbnet1.dal004.pnap.net (216.52.191.19)               3.3%    30    29  60.3  60.2  59.8  60.5
> 15.|-- giglinx-60.border1.dal004.pnap.net (216.52.189.46)               3.3%    30    29  59.9  60.2  59.8  61.4
> 16.|-- 204.109.62.46                                                    6.7%    30    28  60.1  60.5  60.1  62.7
> 17.|-- mambo.koitsu.org (204.109.61.174)                                3.3%    30    29  60.7  60.9  60.1  63.4
> === END
> 
> 
> src IP: 204.109.61.174 (RootBSD; Dallas, TX)
> dst IP: 76.102.14.35   (Comcast; Mountain View, CA)
> 
> === Sat Mar  8 16:22:00 PST 2014  (1394324520)
> Start: Sat Mar  8 16:22:00 2014
> HOST: mambo.koitsu.org                                                Loss%   Snt   Rcv  Last   Avg  Best  Wrst
>  1.|-- 204.109.61.173                                                   0.0%    30    30   0.5   1.3   0.4  15.0
>  2.|-- 204.109.62.45                                                    0.0%    30    30   0.5   0.5   0.3   1.2
>  3.|-- border1.ge1-6.giglinx-60.dal004.pnap.net (216.52.189.45)         0.0%    30    30   0.5   0.6   0.4   4.7
>  4.|-- core3.pc1-bbnet1.ext1a.dal.pnap.net (216.52.191.41)              0.0%    30    30   0.9   1.0   0.9   1.2
>  5.|-- dax-edge-03.inet.qwest.net (67.133.189.93)                       0.0%    30    30   0.6   2.0   0.5  22.8
>  6.|-- 63-235-82-234.dia.static.qwest.net (63.235.82.234)               0.0%    30    30   1.4   1.3   1.0   1.7
>  7.|-- be-13-cr01.dallas.tx.ibone.comcast.net (68.86.82.141)            0.0%    30    30   1.3   2.7   1.0   4.9
>  8.|-- he-0-14-0-0-cr01.losangeles.ca.ibone.comcast.net (68.86.85.141)  0.0%    30    30  35.6  33.6  31.8  35.7
>  9.|-- he-1-8-0-0-ar01.oakland.ca.sfba.comcast.net (68.86.89.54)        3.3%    30    29  52.8  53.5  51.5  55.5
> 10.|-- te-0-4-0-5-ur06.santaclara.ca.sfba.comcast.net (68.86.143.97)    0.0%    30    30  52.1  52.2  51.9  52.3
> 11.|-- te-6-0-acr03.santaclara.ca.sfba.comcast.net (68.86.249.66)       6.7%    30    28  53.0  53.0  52.8  53.8
> 12.|-- c-76-102-14-35.hsd1.ca.comcast.net (76.102.14.35)                3.3%    30    29  60.4  60.5  59.9  63.8
> === END
> 
> -- 
> | Jeremy Chadwick                                   jdc at koitsu.org |
> | UNIX Systems Administrator                http://jdc.koitsu.org/ |
> | Making life hard for others since 1977.             PGP 4BD6C0CB |
> 
> _______________________________________________
> Outages mailing list
> Outages at outages.org
> https://puck.nether.net/mailman/listinfo/outages




More information about the Outages mailing list