packet loss question
Phillip Lynn
phillip.lynn at netwolves.com
Fri Jul 8 13:01:14 UTC 2016
On 07/07/2016 03:52 PM, Ken Chase wrote:
> No offence, but i swear that mtr should come with a license to use it. I get more
> questions from people accusing us of network issues with mtr in hand...
>
> You shoudlnt care that there's 80% packet loss in the middle of your route, unless
> you have actual traffic to lag-101.ear3.miami2.level3.net. I suspect you dont.
> (If you did, you'd have mtr'd to it directly of course.)
>
> As for your second trace, the sudden jump from 0% on 2nd last hop to 100% last
> hop packetloss seems like firewalling to me. (long discussion about the
> probabilities of getting 5 0%pl hops in a row and 100% on an unfirewalled
> endpoint elided. TL;DR: use more packets in your test -i 0.1 -c 100 thanks).
>
> If you have 0% packetloss to your target endpoint, is there an issue here?
> What caused you to mtr? 0% pl is pretty good. You could play quake 1.0
> through that pl and ping time. The +20ms ATL<>CHI jump in the route you'd have
> to take up with einstein/bill nye/$deity.
>
> For the 2nd trace, the 1st hop is your latency issue (plus the big jump from
> miami<>ashburn, again the limit is c.)
>
> ICMP is allowed to be dropped by intervening routers. Someone will quote an RFC
> at us shortly.
>
> Mtr without a return route is not that useful in figuring out packetloss
> because pl requires the packet make it there and back. Pl could be anywhere on
> the return route, which is probably not symmetrical. The internet stopped
> being symetrical about 20+ years ago (if it ever even loosely was), so get a friend
> to send you an mtr to your ip from the farside.
>
> (I remember a project long ago, some cgi-bin (yeah that long ago) that was
> basically a full-path forward+reverse traceroute you could hit on a selected
> server at the provider. Rather handy. not sure if its still a thing, or what it was
> called.)
>
> /kc
>
>
> On Thu, Jul 07, 2016 at 03:17:40PM -0400, Phillip Lynn said:
> >Hi all,
> >
> > I am writing because I do not understand what is happening. I ran mtr
> >against our email server and www.teco.comand below are the results. I am
> >not a network engineer so I am at a loss. I think what I am seeing is
> >maybe a hand off issue, between Frontier and Level3Miami2. If I am correct
> >then what can I do?
> >
> > My system is running Centos 6.5 Linux.
> >
> >Thanks,
> >
> >Phillip
> >
> >
> >
> >(! 1011)-> sudo mtr -r netwolves.securence.com
> >HOST: xxxxx at netwolves.comLoss% Snt Last Avg Best Wrst StDev
> > 1. 172.24.109.1 0.0% 10 0.6 0.6 0.6 0.7 0.0
> > 2. lo0-100.TAMPFL-VFTTP-322.gni 0.0% 10 3.2 2.0 1.0 4.3 1.2
> > 3. 172.99.44.214 0.0% 10 4.0 4.9 2.3 6.9 1.5
> > 4. ae8---0.scr02.mias.fl.fronti 0.0% 10 9.3 9.1 7.5 9.8 1.0
> > 5. ae1---0.cbr01.mias.fl.fronti 0.0% 10 8.9 9.1 7.6 9.7 0.7
> > 6. lag-101.ear3.Miami2.Level3.n 80.0% 10 9.0 8.9 8.8 9.0 0.1
> > 7. 10ge9-14.core1.mia1.he.net 0.0% 10 14.3 13.0 7.6 18.1 4.3
> > 8. 10ge1-1.core1.atl1.he.net 0.0% 10 25.6 33.2 22.4 99.7 23.6
> > 9. 10ge10-4.core1.chi1.he.net 0.0% 10 45.6 51.8 45.5 82.7 12.5
> > 10. 100ge14-2.core1.msp1.he.net 0.0% 10 53.6 63.9 53.6 125.2 21.8
> > 11. t4-2-usi-cr02-mpls-usinterne 0.0% 10 53.2 73.1 53.2 225.6 54.0
> > 12. v102.usi-cr04-mtka.usinterne 0.0% 10 53.2 53.9 53.2 55.3 0.6
> > 13. netwolves.securence.com 0.0% 10 53.4 53.9 53.4 55.4 0.7
> >
> >(! 1014)-> sudo mtr -r www.teco.com
> >HOST: xxxxx at netwolves.comLoss% Snt Last Avg Best Wrst StDev
> > 1. 172.24.109.1 0.0% 10 0.6 0.6 0.6 0.7 0.0
> > 2. lo0-100.TAMPFL-VFTTP-322.gni 0.0% 10 104.8 81.4 1.1 113.2 43.2
> > 3. 172.99.47.198 0.0% 10 115.0 77.8 2.9 115.0 40.2
> > 4. ae7---0.scr01.mias.fl.fronti 0.0% 10 111.1 80.2 8.5 113.5 41.3
> > 5. ae0---0.cbr01.mias.fl.fronti 0.0% 10 105.9 82.2 7.6 115.4 33.8
> > 6. lag-101.ear3.Miami2.Level3.n 70.0% 10 116.1 80.2 8.5 116.1 62.0
> > 7. NTT-level3-80G.Miami.Level3. 0.0% 10 110.0 81.5 9.0 120.3 41.9
> > 8. ae-3.r20.miamfl02.us.bb.gin. 0.0% 10 119.8 84.0 10.0 119.8 38.5
> > 9. ae-4.r23.asbnva02.us.bb.gin. 10.0% 10 137.4 107.6 30.1 142.7 45.7
> > 10. ae-2.r05.asbnva02.us.bb.gin. 0.0% 10 135.0 109.9 36.6 140.0 39.1
> > 11. xe-0-9-0-8.r05.asbnva02.us.c 0.0% 10 147.5 125.6 49.4 165.5 41.1
> > 12. 24.52.112.21 0.0% 10 158.6 124.0 49.6 161.3 41.5
> > 13. 24.52.112.42 0.0% 10 151.0 127.7 52.2 159.0 41.2
> > 14. ??? 100.0 10 0.0 0.0 0.0 0.0 0.0
> >
> >--
> >Phillip Lynn
> >Software Engineer III
> >NetWolves
> >Phone:813-579-3214
> >Fax:813-882-0209
> >Email: phillip.lynn at netwolves.com
> >www.netwolves.com
> >
>
None taken,
We are having issues with our email and loading some web pages. I
used mtr to try and find if there is a possible connection issue. I
just need to understand what is happening , and be able to explain the
output showing the 80% packet loss . We are not pointing fingers, just
looking to understand the issue better.
Thanks
--
Phillip Lynn
Software Engineer III
NetWolves
Phone:813-579-3214
Fax:813-882-0209
Email: phillip.lynn at netwolves.com
www.netwolves.com
More information about the NANOG
mailing list