All client/server communication occurs over a network via packets. Packets contain a header and routing information, as well as the data they carry.
Adaptive Server was one of the first database systems to be built on a network-based client/server architecture. Clients initiate a connection to the server. The connection sends client requests and server responses. Applications can have as many connections open concurrently as they need to perform the required task.
The protocol used between the client and server is known as the Tabular Data Stream™ (TDS), which forms the basis of communication for many Sybase products.