nanog mailing list archives
Re: Long hops on international paths
From: PAUL R BARFORD <pb () cs wisc edu>
Date: Mon, 17 Jan 2022 19:00:30 +0000
Hello Nick, I've added my collaborators to this reply - Esteban can comment on your observation re. Telia. TTL is​ decremented on the paths we're analyzing. What we're curious about is why we're seeing a concentration of hops at a small number of routers that appear on international paths. I expected that when we looked at paths between e.g., US-Asia, US-Europe, US-South America (considering measurements from Ark nodes doing traceroutes to/from those locations), we would see the first instances of routers located the US along the west coast, east coast and south coast respectively. We did not expect to see Chicago as a first hop location in the US and are wondering e.g., if large providers do this to simplify their operations. Hopefully that makes sense. Any further thoughts are appreciated. Regards, PB ________________________________ From: Nick Hilliard <nick () foobar org> Sent: Monday, January 17, 2022 12:36 PM To: PAUL R BARFORD <pb () cs wisc edu> Cc: nanog () nanog org <nanog () nanog org> Subject: Re: Long hops on international paths PAUL R BARFORD wrote on 17/01/2022 18:02:
For example, there is a router operated by Telia (AS1299) in Chicago that has a high concentration of such links.
this doesn't appear to match 1299's public network topology: https://www.teliacarrier.com/our-network.html Is ttl decrement disabled on the test paths you're measuring? Broadly speaking, if you have a point-to-point link from one location to another (or parallel set of links with a common failure path, e.g. waves on a specific fibre path), there's a single router at each end. Nick
Current thread:
- Long hops on international paths PAUL R BARFORD (Jan 17)
- Re: Long hops on international paths Nick Hilliard (Jan 17)
- Re: Long hops on international paths PAUL R BARFORD (Jan 17)
- Re: Long hops on international paths Lukas Tribus (Jan 17)
- Re: Long hops on international paths PAUL R BARFORD (Jan 17)
- Re: Long hops on international paths Christopher Morrow (Jan 17)
- Re: Long hops on international paths Saku Ytti (Jan 17)
- Re: Long hops on international paths PAUL R BARFORD (Jan 18)
- Re: Long hops on international paths Saku Ytti (Jan 18)
- Re: Long hops on international paths Mark Tinka (Jan 18)
- Re: Long hops on international paths Saku Ytti (Jan 18)
- Re: Long hops on international paths Mark Tinka (Jan 18)
- Re: Long hops on international paths PAUL R BARFORD (Jan 17)
- RE: Long hops on international paths Michael Hare via NANOG (Jan 18)
- Re: Long hops on international paths Nick Hilliard (Jan 17)