SQL redundant databases both sets being modified independently yet staying concurrent I have a server in location 1. This location has slow external internet but all the employees. Location 2 has fast external internet but no people are there. I have a mobile app that I would like to connect to location 2 and have an instantaneous sync. between the two databases. What is the proper way to do this? If a field is updated at site 1 the server sends it to 2. If 2 is modified it sends it to site 1. The last change is always used.
SQL Server has various flavours of replication with different capabilities.

It sounds like peer-to-peer transactional replication best fits your needs.