User Manual Owner's manual

58 Rockwell Automation Publication 280E-UM001B-EN-P - July 2012
Chapter 3 Introduction to EtherNet/IP and Device Level Ring Technology
Fully qualified
domain name
A fully qualified domain name (FQDN) is a domain name that includes all higher
level domains relevant to the entity named. If you think of the DNS as a tree-
structure with each node having its own label, a fully qualified domain name for
a specific node would be its label followed by the labels of all the other nodes
between it and the root of the tree. For example, for a host, a FQDN would
include the string that identifies the particular host, plus all domains of which
the host is a part, up to and including the top-level domain (the root domain is
always null). For example, PARIS.NISC.SRI.COM is a fully qualified domain name
for the host at 192.33.33.109.
Gateway A module or set of modules that allows communications between nodes on
dissimilar networks.
Hardware address
Each Ethernet device has a unique hardware address (sometimes
called a MAC address) that is 48 bits. The address appears as six
digits separated by colons (such as, xx:xx:xx:xx:xx:xx). Each digit has
a value between 0 and 255 (0x00 to 0xFF). This address is assigned
in the hardware and cannot be changed. The hardware address is
required to identify the device if you are using a BOOTP utility.
Host name The host name is the unique name for a computer within its domain. It's always
the first element of a full name, and, with its domain and top-level domain
suffix, creates the unique name of that computer on the Internet. For example,
let's say a trading website is www.trading.com. The host name is www, which is
not unique on the web, but is unique within the trading domain.
The host name can also refer to the fully qualified domain name (FQDN), or in
this example, www.trading.com. Both naming methods seem to be used
interchangeably in various documents. For the purposes of this document, the
host name will refer to the FQDN, or as in this example, www.trading.com.
Hub A central connecting device that joins devices together in a star configuration.
Hubs are generally not suitable for use in I/O control systems, since they are
time-critical applications that cannot tolerate lost packets.
Implicit messaging Real-time messaging of I/O data.
IP Internet protocol that provides the routing mechanism for messages. All
messages contain not only the address of the destination station, but the
address of a destination network, which allows messages to be sent to multiple
networks within an organization or around the world.
IP address A 32-bit identification number for each node on an Internet Protocol network.
These addresses are represented as four sets of 8-bit numbers (numbers from 0
to 255), with decimals between them. Each node on the network must have a
unique IP address.
Latency The time between initiating a request for data and the beginning of the actual
data transfer.
Multicast In the CIP producer/consumer model, one producer multicasts (broadcasts) the
data once to all the consumers.
Producer The source of information in the CIP networking model. See CIP.
This Term Means