Comment by to11mtm
6 hours ago
I actually got to see one of those once.
For a major trans-oceanic backbone provider, at least 15ish years ago they had a mile or two between Detroit and Chicago where both ends were on the same side of the interstate highway.
But it's more frequent on DAS (Distributed Antenna Systems, AKA small-cell or micro-cell) networks.
Also the challenge of when fibers are leased (if that's still a thing, based on the networks I helped design I'd say 'probably').
They really are analogous to Lamport's "Distributed System" quip; A damaged fiber owned by a company you have never heard of can wreck your day.
In route one circuit from Washington to London via ashburn and down to Texas before going on subsea circuits through mainland Europe to ensure path diversity. The other heads north east towards Newark and and surfaces in Bude. That took two years of contractural arguments.
Fibres on the Texas link die all the time (yearly) but that’s fine.
My circuits in the far east are often carried one via dues and one via the USA.
It is possible to guarentee diversity, you just need to get specific detail and have good contractual protections.