[j-nsp] Routing Issue

Sat Jul 19 23:02:12 EDT 2008

could be a issue with hashing across multiple links and one link is  
having an issue. one trace can hash to one link and the other, even 1  
ip difference, may hash to another as a different 5-tuple. there have  
been silent discarding reported on multiple vendor boxes over the  
years. not saying this is what the issue is but it is one possible  
explanation. glbx would have to check what their network is seeing.  
another possibility is return path which someone already mentioned.

regards

On Jul 19, 2008, at 7:20 PM, Brendan Mannella  
<bmannella at teraswitch.com> wrote:

> Well yes and here is more weirdness. I reduced the ip by one and it  
> does all the way. And it even appears to be the same server.
>
> Thanks, i will shoot these to NANOG next time. Thanks for the  
> suggestion.
>
> agg1.pit#traceroute 64.14.74.41
> Type Control-c to abort
> Tracing the route to IP node 64.14.74.41 from 1 to 30 hops
>
> 1 <1 ms <1 ms <1 ms 204.16.241.225
> 2 7 ms 7 ms 6 ms 64.209.102.233
> 3 7 ms 6 ms 6 ms te1-3-10g.ar2.DCA3.gblx.net [67.17.108.145]
> 4 6 ms 6 ms 6 ms savvis-1.ar2.DCA3.gblx.net [64.212.107.26]
> 5 45 ms 6 ms 7 ms ber1-tenge-2-1.virginiaequinix.savvis.net  
> [204.70.193.6]
> 6 14 ms 14 ms 15 ms cr1-tengig0-7-2-0.washington.savvis.net [204.70.197.242 
> ]
> 7 21 ms 22 ms 23 ms cr1-pos-0-0-0-0.boston.savvis.net [204.70.193.177]
> 8 20 ms 19 ms 20 ms hr1-pos-1-0-0.Waltham2bo2.savvis.net [208.172.51.66 
> ]
> 9 19 ms 20 ms 19 ms csr1-ve242.Waltham1bo1.savvis.net [64.14.70.19]
> 10 20 ms 19 ms 19 ms 64.14.67.130
> 11 20 ms 20 ms 20 ms s426.sureserver.com [64.14.74.41]
>
> agg1.pit#traceroute 64.14.74.42
> Type Control-c to abort
> Tracing the route to IP node 64.14.74.42 from 1 to 30 hops
>
> 1 <1 ms <1 ms <1 ms 204.16.241.225
> 2 7 ms 6 ms 6 ms 64.209.102.233
> 3 7 ms 7 ms 6 ms te2-1-10G.ar2.DCA3.gblx.net [67.17.105.133]
> 4 * * * ?
> ^C
>
>
> Brendan Mannella
> President and CEO
> TeraSwitch Networks Inc.
> Ph: 412-387-3543
> Mobile: 412-592-7848
> Efax: 412-202-7094
>
> ----- Original Message -----
> From: "Stefan Fouant" <sfouant at gmail.com>
> To: "Brendan Mannella" <bmannella at teraswitch.com>, "juniper-nsp" <juniper-nsp at puck.nether.net 
> >
> Sent: Saturday, July 19, 2008 9:20:26 PM GMT -05:00 US/Canada Eastern
> Subject: Re: [j-nsp] Routing Issue
>
> Are you certain that Savvis has a route to the network in question?
>
> For future reference, these types of questions are perfect for the
> NANOG mailing list.
>
>
>
> On 7/19/08, Brendan Mannella <bmannella at teraswitch.com> wrote:
>> Hello,
>>
>> This is more of a general routing question/issue, but hopefully  
>> someone can
>> help. This week i have been seeing wierd issues were customers are  
>> unable to
>> get to some servers on the internet and its seems that this happens  
>> when the
>> route goes through Savvis.
>>
>> For instance.
>>
>> A customer server on my network running a traceroute to
>> mail.tecumsehherald.com gets the following...
>>
>> orange:~>traceroute mail.tecumsehherald.com
>> traceroute to mail.tecumsehherald.com (64.14.74.42)
>> 1 204.16.245.97 (204.16.245.97) 0.580 ms 0.800 ms 1.020 ms
>> 2 204.16.241.225 (204.16.241.225) 0.496 ms 0.478 ms 0.699 ms
>> 3 64.209.102.233 (64.209.102.233) 7.177 ms 7.420 ms 7.417 ms
>> 4 te1-3-10g.ar2.DCA3.gblx.net (67.17.108.145) 7.630 ms 7.870 ms  
>> 8.105 ms
>> 5 * * *
>> 6 * * *
>>
>> Now if i go to Global Crossings looking glass and run a trace from  
>> their DC
>> router to the same host, it makes it.
>>
>> 1 64.214.14.161 (64.214.14.161) 0.457 ms 0.429 ms
>> 2 te7-1-10G.ar2.DCA3.gblx.net (67.17.109.34) 1.401 ms 1.658 ms
>> 3 savvis-1.ar2.DCA3.gblx.net (64.212.107.26) 1.567 ms 1.339 ms
>> 4 ber1-tenge-2-1.virginiaequinix.savvis.net (204.70.193.6) 1.586 ms  
>> 1.511 ms
>> 5 cr1-tengig0-7-2-0.washington.savvis.net (204.70.197.242) 2.367 ms  
>> 2.547 ms
>> 6 cr1-pos-0-0-0-0.boston.savvis.net (204.70.193.177) 15.163 ms  
>> 15.836 ms
>> 7 hr1-pos-1-0-0.Waltham2bo2.savvis.net (208.172.51.66) 11.702 ms  
>> 11.780 ms
>> 8 csr1-ve242.Waltham1bo1.savvis.net (64.14.70.19) 12.202 ms 11.728 ms
>> 9 64.14.67.130 (64.14.67.130) 11.570 ms 11.592 ms
>> 10 ns2.s426.sureserver.com (64.14.74.42) 11.811 ms 11.927 ms
>>
>> With all of my issues this week, the common thing seems to be  
>> Savvis. But
>> why would it not work just for my network. Its almost like Savvis is
>> blackholeing traffic from my network, but if i run a traceroute to
>> savvis.net, it goes through. So it only appears to be certain hosts.
>>
>> raceroute to www.savvis.net (216.91.182.78), 30 hops max, 40 byte  
>> packets
>> 1 204.16.240.57 (204.16.240.57) 0.538 ms 0.737 ms 0.977 ms
>> 2 204.16.241.225 (204.16.241.225) 0.385 ms 0.438 ms 0.482 ms
>> 3 64.209.102.233 (64.209.102.233) 7.957 ms 7.910 ms 7.865 ms
>> 4 te2-1-10G.ar2.DCA3.gblx.net (67.17.105.133) 7.668 ms 7.112 ms  
>> 8.335 ms
>> 5 savvis-1.ar2.DCA3.gblx.net (64.212.107.26) 6.769 ms 6.753 ms  
>> 6.695 ms
>> 6 er2-tengig2-1.virginiaequinix.savvis.net (204.70.193.102) 6.934  
>> ms 6.891
>> ms 6.836 ms
>> 7 cr2-tengig0-7-3-0.washington.savvis.net (204.70.197.246) 14.571  
>> ms 14.661
>> ms 14.622 ms
>> 8 cr1-tengig-0-0-5-0.chicago.savvis.net (204.70.195.113) 40.376 ms  
>> 40.124 ms
>> 40.660 ms
>> 9 ber1-tengig-9-0-0.Chicago.savvis.net (204.70.195.114) 32.512 ms  
>> 32.612 ms
>> 32.488 ms
>> 10 acr1-ge-1-1-0.chicago.savvis.net (204.70.204.206) 32.922 ms  
>> 32.904 ms
>> 32.971 ms
>> 11 scr1-stls6.sec.savvis.net (208.172.1.138) 38.814 ms 38.895 ms  
>> 38.838 ms
>> 12 64.241.46.5 (64.241.46.5) 38.637 ms 38.584 ms 38.785 ms
>>
>>
>> Does anyone have any ideas?
>>
>> Brendan
>>
>>
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>>
>
> -- 
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>
> Stefan Fouant
> Principal Network Engineer
> NeuStar, Inc. - http://www.neustar.biz
> GPG Key ID: 0xB5E3803D
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