Sybase DC35823-01-1500-04 - Manual (Page 27)

CHAPTER 1 Introduction
Configuration Guide 11
Client/server communication
Adaptive Server communicates with other Adaptive Servers, Open Server™
applications (such as Backup Server), and client software on your network.
Clients can talk to one or more servers, and servers can communicate with
other servers by remote procedure calls.
For Sybase products to interact with one another, each product needs to know
where the others reside on the network. Names and addresses of every known
server are listed in a directory services file. This information can be stored in a
directory services file two different ways:
• In an interfaces file, named interfaces on UNIX platforms, located in the
$SYBASE installation directory, or
• In an LDAP server
After your Adaptive Server or client software is installed, it can connect with
any server on the network that is listed in the directory services.
When you are using a client program, and you want to connect with a particular
server, the client program looks up the server name in the directory services
and connects to that server, as shown in Figure 1-1. You can supply the name
of the server by using the DSQUERY environment variable.
On TCP/IP networks, the port number gives clients a way to identify the
Adaptive Server, Open Server, Backup Server, or Monitor Server to which they
want to connect. It also tells the server where to listen for incoming connection
attempts from clients. The server uses a single port for these two services
(referred to as query service and listener service).