Rockwell Automation 1203-EN1 EtherNet/IP-to-SCANport Module - Manual (Page 176)

G-8 Glossary
SCANport Product
A device that uses the SCANport communications interface to
communicate with one or more peripheral devices. For example, a motor
drive such as a 1336 PLUS II drive is a SCANport product. In this
manual, a SCANport product is also referred to as “drive” or “host.”
Status Indicators
Status indicators are LEDs that are used to report the status of the
module, network, and drive.
Subnet Masks
A subnet mask is an extension to the IP addressing scheme that lets you
use a single network ID for multiple physical networks. A bit mask
identifies the part of the address that specifies the network and the part of
the address that specifies the unique node on the network. A “1” in the
subnet mask indicates the bit is used to specify the network. A “0” in the
subnet mask indicates that the bit is used to specify the node.
For example, a subnet mask on a Class C address may appear as follows:
11111111 11111111 11111111 11000000 (255.255.255.192). This mask
indicates that 26 bits are used to identify the network and 6 bits are used
to identify devices on each network. Instead of a single physical Class C
network with 254 devices, this subnet mask divides it into four networks
with up to 62 devices each.
Switches
Switches are network devices that provide virtual connections that help
to control collisions and reduce traffic on the network. They are able to
reduce network congestion by transmitting packets to an individual port
only if they are destined for the connected device. In a control
application, in which real time data access is critical, network switches
may be required in place of hubs.
T
TCP (Transmission Control Protocol)
EtherNet/IP uses this protocol to transfer Explicit Messaging packets
using IP. TCP guarantees delivery of data through the use of retries.
U
UDP (User Datagram Protocol)
EtherNet/IP uses this protocol to transfer I/O packets using IP. UDP
provides a simple, but fast capability to send I/O messaging packets
between devices. This protocol ensures that modules transmit the most
recent data because it does not use acknowledgements or retries.