This issue now seems resolved. If anyone here was directly responsible for the resolution, thank you. -Vinny Vinny Abello via NANOG wrote on 6/11/2021 11:17 AM:
Hello,
Please excuse the noise. If there are any network engineers from Cogent and Altice on the list, could you please email me directly. This is regarding a specific Altice IPv4 aggregate in the NYC area that Cogent in the NYC area is handing off to Zayo in San Jose for some reason. It subsequently seemingly has a lot of packet loss coming back to the NYC area through Zayo's network. It's affecting my remote employees.
I can provide traceroutes privately as not to clutter up the list.
Bad Altice Aggregate in question: 67.84.0.0/14
Good Altice aggregate routing properly: 68.196.0.0/14
Thanks in advance.
-Vinny