I know the best practice would be to have the PDC Emulator to sync against an external NTP time source, and have all other domain controllers sync against the PDC Emulator.
However, my network layout is... 'interesting', to say the least.
My company is a multinational company. For reasons unknown to mere mortals, the group headquarter (located in another country) demands all country-branch-offices to connect directly to the group headquarter instead of the country-head-office. The PDC Emulator is located in the country-head-office.
But the domain is country-wide, not global.
In other words, it's a "hub and spoke" arrangement... but with the PDC Emulator located in one spoke instead of in the hub.
Now, group HQ is 'kind enough' to provide a time reference server; let's call it ntp.bigcompany.com. I already had my PDC Emulator sync against that time reference.
The million dollar question: In your opinion, should I keep doing it the 'recommended' way (i.e., have branch DCs sync to the PDC Emulator), or should I force all DCs to sync to ntp.bigcompany.com?
Edited to add: Just to make things clearer, all offices (branch or head) in my country has NO direct Internet connectivity; all offices are connected to HQ via VPN. There's a proxy farm in the HQ to serve the web browsers in branch-/head-office. NTP traffic to public Internet NTP servers are blocked.