Ha, my apologies, I thought I was writing this for a Linux User Group, not a NOG. Ignore my simplistic explanations. - Thomas Scott | mr.thomas.sc...@gmail.com
On Wed, Nov 24, 2021 at 12:47 PM Thomas Scott <mr.thomas.sc...@gmail.com> wrote: > I have used it successfully in a test environment that I was using ECMP > in. Most of the public networks that I've worked with don't use ECMP as > often as other methods for steering traffic (LAGs, BGP MEDs, etc). > > What I have seen it fantastically useful for was troubleshooting a transit > provider, or for when they were congested or had a flapping core link. > Granted I *think *it's still subject to ICMP deprioritization (most SP's > use it prodigiously), and most MPLS cores don't decrement TTL, but it was > still useful to be able to show them "no, at this IP, I *always* drop > traffic, when..." > > - Thomas Scott | mr.thomas.sc...@gmail.com > > > On Wed, Nov 24, 2021 at 12:23 PM Adam Thompson <athomp...@merlin.mb.ca> > wrote: > >> The tool fbtracert (http://github.com/facebookarchive/fbtracert) was >> mentioned here recently as a way to get visibility into multi-pathing. >> >> Has anyone here ever used this tool successfully? >> >> >> >> Supposedly Facebook uses this tool internally, but… that doesn’t help >> much. >> >> >> >> I’ve tried it on 4 different platforms/OSes (WSL Ubuntu; RedHat; Debian; >> OpenBSD), and versions of Go (v1.10 through v1.16), in three very different >> environments (on-prem public IP; on-prem NAT’d; cloud public IP), and I’ve >> yet to see it produce any meaningful output – each run/iteration/thread >> only detects one, single, hop out of the entire chain of routers, making it >> less than useful. Granted, that’s not a full regression test by any means, >> but if anyone here has ever used it successfully, could you please let me >> know what sort of environment you ran it in/on? >> >> >> >> Thanks, >> >> -Adam >> >> >> >> *Adam Thompson* >> Consultant, Infrastructure Services >> [image: 1593169877849] >> 100 - 135 Innovation Drive >> Winnipeg, MB, R3T 6A8 >> (204) 977-6824 or 1-800-430-6404 (MB only) >> athomp...@merlin.mb.ca >> www.merlin.mb.ca >> >> >> >