Clients and Servers on Separate Hosts

This is the commonly understood meaning of client/server computing where the server resides on one host system and clients can reside on one or multiple additional computer systems. If all of the clients connect to the same server, this is known as a two-tier architecture. If there are multiple servers that do different types of work and can each one can connect to multiple clients, this is known as a multi-tier architecture. A common type of three-tier architecture (a subset of multi-tier) is a case in which one server holds data, one holds business rules, and the clients connect transparently to both servers. These types of connections are referred to a remote connections.

There are two network protocols over which Informix can talk to connect remote clients and servers:

• TCP/IP (Transmission Control Protocol/Internet Protocol): This is the most common protocol and is the protocol used for all Internet connectivity. This chapter will concentrate on TCP/IP connections for remote connections.

• IPX/SPX: This protocol is only used for NetWare networks. If there is a UNIX machine involved, it must have IPX/SPX software installed.