The problem with traceroute is that it won’t show that two different ISPs are leasing strands out of the same bundle.
All of the unexpected shared infra issues I’ve observed have been down at this lower level that never shows up at the IP layer.
All of the unexpected shared infra issues I’ve observed have been down at this lower level that never shows up at the IP layer.
I worked at two small ISPs, each with a fiber network spanning a few US states. They had their own databases to track this information, but as far as I know there was no central database. One of them used OSPInsight backed by a self-hosted SQL Server database. I don't know what the other place used.