I have questions regarding the Exchange architecture, design and functionment.
We have 3 sites on 3 different continents with an Exchange 2010 server on each site (CAS, Mailbox server and hub transport roles).
The 3 exchange servers are in the same DAG and all databases are replicated on all sites.
We domain controllers on each site with a single AD Forest with different sites.
I assume below that our users connect to a LAN with a VPN between each site.
1- When one user from site A travels to site B (where resides a copy of the database for HA) , on which Exchange server does the outlook client connect?
I cannot imagine that a user travelling in China (where our internet bandwidth is really slower than in US or Europe) would connect to the remote server and have very slow response.
2- When one user from site A travels to site B (where resides a copy of the database for HA) , and sends an email to another user in site B, what is the route of the mail ? Site B--> site B OR site B--> site A --> site B ?
3- If the server in site A fails, where will connect my traveling user if he is on site B (with an exchange server on site) but without internet connection? In other words, will he be able to send emails to another local user on site B?
4- If internet connection between Site A and Site B is down and the database on Site B is promoted as active, what happens when the link is restored? Does Site B send its updates to Site A then become inactive again?
Thank you for your help :-)