324 • Glossary
Modular I/O System
ETHERNET TCP/IP
Routing
Method of selecting the best path over which to send data to a distant net-
work.
S
SCADA
Abbreviation for Supervisory Control and Data Acquisition. SCADA soft-
ware is a program for the control and visualization of processes.
Segment
Typically, a network is divided up into different physical network segments
by way of routers or repeaters.
Server
Device providing services within a client/server system. The service is re-
quested by the Client.
Service
An operation targeted at an object (read, write).
Socket
Is a software interface introduced with BSD-UNIX for inter-process com-
munication. Sockets are also possible in the network via TCP/IP. As from
Windows 3.11, they are also available in Microsoft operating systems.
Structured cabling
This specifies the maximum permissible cable lengths (EIA/TIA 568, IS
11801) and gives recommendations for the different types topology for
ground area, building and floor cabling.
Subnet
A portion of a network that shares the same network address as the other
portions. These subnets are distinguished through the subnet mask.
Subnet mask
The subnet mask can be used to manipulate the address areas in the IP ad-
dress room with reference to the number of subnets and subscribers. A stan-
dard subnet mask is, for example, 255.255.255.0.