GE GFK-1541B - Manual (Page 199)

A-6 TCP/IP Ethernet Communications for the Series 90™ PLC User's Manual – May 2002 GFK-1541B
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called “transceiver”. The MAU may be built into the DTE or it may be a separate unit that
attaches to the DTE through an AUI.
Modbus A data transfer protocol. Called Modbus/TCP when Ethernet media is used, called
Modbus/RTU (or simply “Modbus”) when serial media is used.
Multicast The transmission scheme in which a limited group of multiple receivers are the
intended target of a transmission.
Multicast Address A LAN group address that identifies a subset of the network nodes on a
Local Area Network.
Multiple Gateway Routing The capability of an Ethernet Interface to route a received message
to either the default gateway or one of additional gateways configured at the Ethernet
Interface.
Name Resolution A “hidden” process that permits application programs to address network
nodes using a symbolic name (Network Address Name) in lieu of a numeric IP address.
Netid The netid is the part of the IP address identifying the network on which the node resides.
(See also Hostid.)
Network An arrangement of nodes and interconnecting branches.
Network Adapter The device, such as the Ethernet Interface, providing communications
services for a particular network.
Network Address Name A character string that is used in lieu of an IP address. The client
and/or server device uses Name Resolution to resolve this symbolic name into the actual IP
address. This name represents the address on the network of a particular network adapter.
Also referred to as “Adapter Name”.
Network Switch An Ethernet device that dynamically connects two communicating nodes
without propagating the data to other Ethernet devices also connected to the switch.
Node The physical module that connects a node to the network. The Ethernet Interface is an
example of a node. It connects a station (PLC or CNC) to a network (Factory LAN). A
station may contain more than one Ethernet Interface and therefore contains more than one
node.
Octet A group of 8 bits operated on as a single unit. (See also Byte.)
One-Way Propagation Time See Transmission Path Delay.
Path The sequence of segments and repeaters providing the connectivity between two DTEs. In
CSMA/CD networks, there is one and only one path between any two DTEs.
Peer Another entity at the same level (layer) in the communication hierarchy.
Peer-Peer Communication between nodes at the same level or layer in the hierarchy.
Physical Address The unique physical layer address associated with a particular node on the
Local Area Network (LAN). Ethernet physical addresses are typically assigned by the
manufacturer. (See for comparison, Internet Address.)
Producer In Ethernet Global Data, a device (such as a PLC) that periodically produces new
samples of data (data exchange). (See also Consumer, Exchange.)
Producer ID In Ethernet Global Data, a dotted-decimal number used to uniquely identify a
Producer device (such as an entire PLC system) on the network. (See also Producer,
Consumer, and Exchange.)