Publication 1734-UM011A-EN-P - February 2004
Preface 7
Ethernet network A local area network designed for the high-speed exchange of
information between computers and related devices.
explicit messaging Non-time critical messaging used for device configuration and data
collection,suchasdownloadingprogramsor peer-to-peermessaging
between two PLCs.
full duplex A mode of communication that allows a device to send and receive
information at the same time, effectively doubling the bandwidth.
fully qualified
domain name A Fully Qualified Domain Name (FQDN) is a domain name that
includes all higher level domains relevantto the entity named. If you
think of the DNS as a tree-structure with each node having its own
label,a FullyQualifiedDomainNameforaspecificnode wouldbeits
labelfollowed bythelabelsofall theother nodesbetween itandthe
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 (i.e., 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 TheHost Nameis theunique namefor a computerwithin itsdomain.
It's always the first element of a full name, and, with its domain and
top-leveldomainsuffix, createstheuniquenameofthatcomputeron
the Internet. For example, let's say a trading website is
www.trading.com.The HostName is“www”,which isnot uniqueon
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,sincetheyaretime criticalapplicationsthat cannottolerate
lost packets.
implicit messaging Real time messaging of I/O data.
IP Internet Protocol that provides the routing mechanism for messages.
Allmessagescontain notonly the addressof thedestination 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(numbersfrom0to255),withdecimalsbetweenthem.Each
node on the network must have a unique IP address.
This term Means
