NTP packets eaten by TATA Communications?



within the last few weeks I got a few alarm messages by my monitoring system because it failed to contact my NTP server.
I made some debugging and noticed:

NTP packets sent by my monitoring server arrived on my NTP system.
My system sends answers to each packet (visible with tcpdump on egress interface), but some of these answers never reaches my network border router.

Then I fiddled around with route advertisements and noticed that every time TATA communications is involved in routing, NTP packets get sporadically lost.

Has anyone problems with their NTP (pool) servers and observes routers of TATA in a traceroute originating from the monitoring network?
(Add your server’s hostname or IP address at the end of the URL)

TATA is usually identified by the name “as6453.net” in a traceroute’s hop.

That may (or may not) explain intermittent problems with NTP pool servers which are dropping out of the pool with no obvious reason.