RE: Help me make sense of these traceroutes please
Thanks to everyone who responded off list and on. Sam Moats On 2013-12-26 11:21, Josephson, Marcus wrote: Start at slide 50: This is documented further by the following Nanog presentation. http://www.nanog.org/meetings/nanog47/presentations/Sunday/RAS_Traceroute_N47_Sun.pdf -Marcus -Original Message- From: Jimmy Hess [mailto:mysi...@gmail.com] Sent: Wednesday, December 25, 2013 10:28 AM To: Martin Hotze Cc: nanog@nanog.org Subject: Re: Help me make sense of these traceroutes please On Wed, Dec 25, 2013 at 8:03 AM, Martin Hotze m.ho...@hotze.com wrote: On 2013-12-25 00:16, Sam Moats wrote: ... You are likely seeing the effects of asymmetric routing. . .. or the effect of passing traffic through NSA infrastructure. Ah... NSA. That's probably it. So much for my theory of a Router virtual chassis straddling the atlantic. or the extra kinetic energy carried by the overseas-bound packet took longer for the router to absorb and rebound with an ICMP. But in all seriousness --- what is probably happening here, is the result of extra hops that don't show up in traceroute. MPLS tunnels could well fit the bill. Other things to consider when latency seems sensitive to destination IP --- are preceding device in the traceroute might also have multiple links to the same device; with one link congested and some form of IP-based load sharing, that happens to be the toward-overseas link. SCNR, #m -- -JH
RE: Help me make sense of these traceroutes please
Start at slide 50: This is documented further by the following Nanog presentation. http://www.nanog.org/meetings/nanog47/presentations/Sunday/RAS_Traceroute_N47_Sun.pdf -Marcus -Original Message- From: Jimmy Hess [mailto:mysi...@gmail.com] Sent: Wednesday, December 25, 2013 10:28 AM To: Martin Hotze Cc: nanog@nanog.org Subject: Re: Help me make sense of these traceroutes please On Wed, Dec 25, 2013 at 8:03 AM, Martin Hotze m.ho...@hotze.com wrote: On 2013-12-25 00:16, Sam Moats wrote: ... You are likely seeing the effects of asymmetric routing. . .. or the effect of passing traffic through NSA infrastructure. Ah... NSA. That's probably it. So much for my theory of a Router virtual chassis straddling the atlantic. or the extra kinetic energy carried by the overseas-bound packet took longer for the router to absorb and rebound with an ICMP. But in all seriousness --- what is probably happening here, is the result of extra hops that don't show up in traceroute. MPLS tunnels could well fit the bill. Other things to consider when latency seems sensitive to destination IP --- are preceding device in the traceroute might also have multiple links to the same device; with one link congested and some form of IP-based load sharing, that happens to be the toward-overseas link. SCNR, #m -- -JH
Re: Help me make sense of these traceroutes please
From: Jeroen Massar jer...@massar.ch To: s...@circlenet.us, nanog@nanog.org Subject: Re: Help me make sense of these traceroutes please On 2013-12-25 00:16, Sam Moats wrote: Hello Nanog community, I would like to enlist your help with understanding this latency I'm seeing. You are likely seeing the effects of asymmetric routing. . .. or the effect of passing traffic through NSA infrastructure. SCNR, #m
Re: Help me make sense of these traceroutes please
On Wed, Dec 25, 2013 at 8:03 AM, Martin Hotze m.ho...@hotze.com wrote: On 2013-12-25 00:16, Sam Moats wrote: ... You are likely seeing the effects of asymmetric routing. . .. or the effect of passing traffic through NSA infrastructure. Ah... NSA. That's probably it. So much for my theory of a Router virtual chassis straddling the atlantic. or the extra kinetic energy carried by the overseas-bound packet took longer for the router to absorb and rebound with an ICMP. But in all seriousness --- what is probably happening here, is the result of extra hops that don't show up in traceroute. MPLS tunnels could well fit the bill. Other things to consider when latency seems sensitive to destination IP --- are preceding device in the traceroute might also have multiple links to the same device; with one link congested and some form of IP-based load sharing, that happens to be the toward-overseas link. SCNR, #m -- -JH
Re: Help me make sense of these traceroutes please
On Tue, 24 Dec 2013 19:03:02 -0500, Sam Moats said: Also you'd be amazed how many network issues can be solved with a bunch of IT folks and an ample supply of Guinness I once heard the claim that if you couldn't explain your network design and have the listener understand it after you had split a pitcher of Guiness, it was probably too complicated. pgpwmQleyV_4U.pgp Description: PGP signature
Re: Help me make sense of these traceroutes please
with a bunch of IT folks and an ample supply of Guinness. My ex used to call it design fluid. :-) Happy holidays, everyone! Anne Anne P. Mitchell, Attorney at Law CEO/President ISIPP SuretyMail Email Accreditation http://www.ISIPP.com Member, Cal. Bar Cyberspace Law Committee Author: Section 6 of the CAN-SPAM Act of 2003 How do you get to the inbox instead of the spam filter? SuretyMail! Helping businesses keep their email out of the junk folder since 1998 http://www.isipp.com/SuretyMail Author, They're Your Kids Too: The Single Father's Guide to Defending Your Fatherhood in a Broken Family Law System http://www.amazon.com/Theyre-Your-Kids-Too-Fatherhood/dp/061551443X
Re: Help me make sense of these traceroutes please
Pitcher of Guinness!?! What blasphemy is this, the only way to drink it is via individually poured pint glasses. Back to the issues I'd say MPLS or GHCQ before NSA. On 25 Dec 2013 15:52, valdis.kletni...@vt.edu wrote: On Tue, 24 Dec 2013 19:03:02 -0500, Sam Moats said: Also you'd be amazed how many network issues can be solved with a bunch of IT folks and an ample supply of Guinness I once heard the claim that if you couldn't explain your network design and have the listener understand it after you had split a pitcher of Guiness, it was probably too complicated.
Re: Help me make sense of these traceroutes please
Thats why you're a bacon zombie. If you were a living person you'd know free beer tastes the same irrespective of the containment vessel. ;) I hope Santa brought all of you what you wanted. If not, blame UPS. Sent from my Mobile Device. Original message From: Bacon Zombie baconzom...@gmail.com Date: 12/25/2013 11:24 AM (GMT-09:00) To: valdis.kletni...@vt.edu Cc: s...@circlenet.us,nanog@nanog.org Subject: Re: Help me make sense of these traceroutes please Pitcher of Guinness!?! What blasphemy is this, the only way to drink it is via individually poured pint glasses. Back to the issues I'd say MPLS or GHCQ before NSA. On 25 Dec 2013 15:52, valdis.kletni...@vt.edu wrote: On Tue, 24 Dec 2013 19:03:02 -0500, Sam Moats said: Also you'd be amazed how many network issues can be solved with a bunch of IT folks and an ample supply of Guinness I once heard the claim that if you couldn't explain your network design and have the listener understand it after you had split a pitcher of Guiness, it was probably too complicated.
Re: Help me make sense of these traceroutes please
On 2013-12-25 00:16, Sam Moats wrote: Hello Nanog community, I would like to enlist your help with understanding this latency I'm seeing. You are likely seeing the effects of asymmetric routing. [..] Tracing route to xxx.yyy.ie [193.1.x.x] www.heanet.ie by chance? :) Though you could use for instance: http://planchet.heanet.ie/toolkit/gui/reverse_traceroute.cgi to do a reverse traceroute, do make sure you force your connectivity to IPv4 as that host will do IPv6 too. (locally nullrouting the destination /128 is the trick I use for 'disabling' IPv6 temporarily). Otherwise the HEANET folks are extremely helpful and clued in, you can always ask them for help with issues. It is the end-of-year though and those Irish folks have lots of really good whiskey, Guinness thus you might have to be patient till the new year. Alternatively, you could use a tool like 'tracepath' or 'mtr' as those reports multiple answers to a response and also check for the TTL on the return packets. Greets, Jeroen
Re: Help me make sense of these traceroutes please
On 2013-12-24 18:55, Jeroen Massar wrote: On 2013-12-25 00:16, Sam Moats wrote: Hello Nanog community, I would like to enlist your help with understanding this latency I'm seeing. You are likely seeing the effects of asymmetric routing. That's what I was thinking to. [..] Tracing route to xxx.yyy.ie [193.1.x.x] www.heanet.ie by chance? :) Yes they were the owners of the IP I used for the example case and the heanet folks are actually totally awesome :-) Though you could use for instance: http://planchet.heanet.ie/toolkit/gui/reverse_traceroute.cgi to do a reverse traceroute, do make sure you force your connectivity to IPv4 as that host will do IPv6 too. (locally nullrouting the destination /128 is the trick I use for 'disabling' IPv6 temporarily). Otherwise the HEANET folks are extremely helpful and clued in, you can always ask them for help with issues. It is the end-of-year though and those Irish folks have lots of really good whiskey, Guinness thus you might have to be patient till the new year. Also you'd be amazed how many network issues can be solved with a bunch of IT folks and an ample supply of Guinness Alternatively, you could use a tool like 'tracepath' or 'mtr' as those reports multiple answers to a response and also check for the TTL on the return packets. Greets, Jeroen Thanks, this isn't affecting my service now I've worked around it so it's more a curiosity than anything. It seems really odd to me that the same L3 edge router would route the ICMP unreachable back to me via different paths based on the final destination IP of the of the ICMP echo packet. Well its Christmas eve here and the customers are happy so Guinness seems like the best approach now :-) Thanks and have a good Holiday, Sam Moats
Re: Help me make sense of these traceroutes please
On 25 December 2013 00:03, Sam Moats s...@circlenet.us wrote: On 2013-12-24 18:55, Jeroen Massar wrote: On 2013-12-25 00:16, Sam Moats wrote: Hello Nanog community, I would like to enlist your help with understanding this latency I'm seeing. You are likely seeing the effects of asymmetric routing. That's what I was thinking to. [..] Tracing route to xxx.yyy.ie [193.1.x.x] www.heanet.ie by chance? :) Yes they were the owners of the IP I used for the example case and the heanet folks are actually totally awesome :-) Though you could use for instance: http://planchet.heanet.ie/toolkit/gui/reverse_traceroute.cgi to do a reverse traceroute, do make sure you force your connectivity to IPv4 as that host will do IPv6 too. (locally nullrouting the destination /128 is the trick I use for 'disabling' IPv6 temporarily). Otherwise the HEANET folks are extremely helpful and clued in, you can always ask them for help with issues. It is the end-of-year though and those Irish folks have lots of really good whiskey, Guinness thus you might have to be patient till the new year. Also you'd be amazed how many network issues can be solved with a bunch of IT folks and an ample supply of Guinness Alternatively, you could use a tool like 'tracepath' or 'mtr' as those reports multiple answers to a response and also check for the TTL on the return packets. Greets, Jeroen Thanks, this isn't affecting my service now I've worked around it so it's more a curiosity than anything. It seems really odd to me that the same L3 edge router would route the ICMP unreachable back to me via different paths based on the final destination IP of the of the ICMP echo packet. Based on the data you provided, my guess is some kind of MPLS transport (please refer to https://www.nanog.org/meetings/nanog45/presentations/Sunday/RAS_traceroute_N45.pdf, pages 46-48). HTH. Well its Christmas eve here and the customers are happy so Guinness seems like the best approach now :-) Thanks and have a good Holiday, Sam Moats
