Some synchronization technologies rely on the presence of a continuous, or at least almost continuous, connection between the databases. Through this connection, the two databases conduct an ongoing dialog. These types of systems excel at replicating changes quickly. Given sufficient resources and channel capacity, synchronization can occur reliably with a lag time of no more than a few seconds.

The main drawback of this type of system is that a reliable, continuous connection can be expensive to maintain. This restriction makes connection-based technologies suited to replication between two large, fixed databases. In environments where the remote computers are mobile or are only occasionally connected, session-based (MobiLink) or message-based (SQL Remote) technologies provide more flexible solutions.

To create a connection-based synchronization system with SQL Anywhere, you need to use Sybase Replication Server. See Replicating data with Replication Server.