2.Terms and Definitions 
 
2.  Terms and Definitions 
 
The terms and definitions used in this guide are given below.   
 
Term  Explanation and Definition 
node  A node refers to a relay point, a junction point or an end point on an 
EtherNet/IP network made up of devices having an EtherNet/IP port.   
A device with one EtherNet/IP port is recognized as one node and two 
EtherNet/IP ports as two nodes on an EtherNet/IP network.   
tag  A tag is a unit that is used to exchange data with tag data links.   
Data is exchanged between the local network variables and remote 
network variables specified in the tags or between specified I/O memory 
areas.   
tag set  When a connection is established, from 1 to 8 tags (including Controller 
status) is configured as a tag set. Each tag set represents the data that is 
linked for a tag data link connection. Tag data links are therefore created 
through a connection between one tag set and another tag set.   
A tag set name must be set for each tag set. 
tag data links  The standard EtherNet/IP implicit communications are called tag data 
links. Tag data links enable cyclic tag data exchanges on an EtherNet/IP 
network between Controllers or between Controllers and other devices.   
connection  A connection is used to exchange data as a unit within which data 
concurrency is maintained.   
connection type  There are two kinds of connection types for tag data links.   
One is a multi-cast connection, and the other is a unicast (point-to-point) 
connection. The multi-cast connection sends an output tag set in one 
packet to more than one node. The unicast connection separately sends 
one output tag set to each node. Therefore, the multi-cast connection 
can reduce the communications load if one output tag set is sent to more 
than one node.   
originator and target  To perform tag data links, it is necessary to open connections between 
nodes that perform tag data links. The node that requests the connection 
is called the originator, and the node that receives the request is called 
the target.   
tag data link 
parameters 
The information that is set to perform tag data links, including tags, tag 
sets and connections, is called tag data link parameters.   
EDS file  A file that describes information unique to a device such as the number 
of I/O points for an EtherNet/IP device. The connections that define the 
tag data links can be set by installing this file in Network Configurator.