5 Implementation of EtherNet/IP
5.1 The EtherNet/IP communications profile
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XI/ON: XNE-GWBR-2ETH-IP
09/2011 MN05002007Z-EN
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Point to point
A connection that exists between two nodes only.
Multicast
A packet with a special destination address, which multiple nodes on the network may be
willing to receive.
COS I/O Connection
COS (Change Of State) I/O Connections establish event-controlled connections. This means
that the EtherNet/IP devices generate messages as soon as a change of status occurs.
Cyclic I/O Connection
Messages are triggered time-controlled in Cyclic I/O connections by means of a time
generator.
UCMM
The EtherNet/IP gateway offers the option of establishing explicit messaging via the UCMM
port (Unconnected Message Manager Port).
UCMM-based explicit messaging is normally used for random, non-periodic requests. It is not
recommended for frequent messaging because the UCMM input queue in a product is typi-
cally limited to just a few messages. Once this limit is reached, subsequent requests are
ignored and must be retried.
Connected Explicit messaging
CIP is a connection-based system. For most communications between nodes, a connection
is used.
A connection is a path or a virtual circuit between two or more end points in a system. The
purpose is to transfer data in the most efficient manner possible.
The Connection ID is a number that is associated with a communication relationship.
Receiving nodes decode this key to know whether they must accept the data or not.
