It would appear that large chunks of TATA in APAC are unreachable from Cogent now, by the looks of it due to Cogent depeering TATA in APAC.

Networks that are single homed behind AS6453 (At least in APAC/India) or AS174 will not be able to reach each other. This is similar but more serious to the previous regional NTT-Cogent depeerings (since those ones were just in the Europe region, and raised latency instead of full unreachability)

This seems to come off the back of Cogent trying to establish a market in APAC, and the main players in that region not wanting to have their market eaten away by Cogent (To be fair, Cogent is very good at getting prices down, and APAC is still quite expensive per mbps).

A snippet of a Cogent ticket says:

Despite Cogent’s repeated requests, TATA has consistently refused to establish connectivity in Asia, taking advantage of Cogent’s good faith efforts while also ensuring sub-standard service to both companies customers. No amount of good will and good faith augments on Cogent’s part has brought TATA any closer to the negotiating table for a resolution to the lack of connectivity in Asia. This one-sided situation has become untenable and as a result, Cogent has elected to start the process of restricting connectivity to TATA.

Estimated damage is that 1575 ASNs now have (more) connectivity issues, 930 (Cogent customers) + 645 (TATA customers)