NETLink
®
Switch
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HMI
Human-Machine Interface denotes the interface between the human op-
erator and a system through which the operator can operate the system or
intervene in the process
HSA
Highest station address that is polled
Hub
A mediation system between LAN segments. Unlike a switch, on a hub, all
data arising in the Ethernet are applied to all ports
Interfaces General
definition
of interfaces, such as a network interface card that con-
stitutes an Ethernet interface
IP address
Internet protocol address. The IP is the address of a device in a network at
which it can be reached. It consists of four bytes and is expressed in deci-
mal notation. Example: 192.168.4.49
ISO on top
of TCP
see RFC1006
LAN
Local area network, a network of computers that are relatively close to
each other physically.
MAC
address
The Media Access Control address is used only once for each single net-
work component that is not changeable. It consists of 6 bytes and is writ-
ten in hexadecimal notation. Example: 08-FF-FA-9C-ED-5A
Master
Is and active station that is permitted to transmit data to and request data
from other stations, when it holds the token
MDI / MDI-
X Auto
Crossover
Makes it possible to identify if a cross over or a straight cable is connected
and configures the port accordingly.
MLFB
16-digit Siemens identification number
MPI
Multipoint Interface. Interface that is used for S7-300 and S7-400 systems
and that supports baud rates up to 1.5 Mbps
NAT
Network Address Translation is the collective term for procedures for re-
placing address information in data packets by other address information
in an automated and transparent way. This is very useful when connecting
private networks via a public line.
Net mask
See subnet mask
Network
rules
Network rules determine how the different data packets are handled in a
network device. For example, data packets are blocked or forwarded to or
from certain network stations
OPC
Object Linking and Embedding for Process Control allows data transfer
between applications of different producers, for example, using the RFC10-
06 protocol
PAT
Port address translation. Used when multiple private IP addresses of a LAN
need to be translated into one public IP address
PG socket
The programming unit socket of the bus connector allows further bus
nodes to be plugged in.
Port
These are address components that are used in network protocols to assign
the correct protocols to data segments, also using port forwarding.
Port
forwarding
The passing on of requests to ports via a network.