Rockwell Automation 1756-ENET/B ControlLogix Ethernet Communication Interface Module User Manual - Manual (Page 12)

Publication 1756-UM051B-EN-P - November 2000
P-6 About This User Manual
Terminology
This term Means
bandwidth The transmission capacity of the network, expressed in bits per
second. Traditional Ethernet has a 10Mbit bandwidth. Fast
Ethernet is 100Mbit.
BootP BootP (Bootstrap Protocol) is a low-level protocol that provides
configurations to other nodes on a TCP/IP network. BootP
configuration files let you automatically assign IP addresses to
an Ethernet module (you can also obtain subnet masks and
gateway addresses from BootP).
The Ethernet module factory default is BootP enabled. Upon
powerup, the module sends a message containing its hardware
address to the BootP server on the network. The server is a
computer with BootP server software installed. The server
compares that hardware address to those in its lookup table in
the configuration file and sends a message back to the module
with the appropriate IP address.
bridge An internetwork node between two similar communication
subnets where protocol translation is minimal.
CIP Control and Information Protocol, the Ethernet/IP application
layer. CIP uses the “producer/consumer” networking model. In
this model one producer broadcasts (multicasts) the data once to
all the consumers. All consumers see the data simultaneously,
and may choose whether to consume (receive) the data or not.
Delivery time is consistent, no matter how many consumers
there are.
consumer A destination device in the CIP networking model. See CIP.
CSMA/CD Carrier Sense Multiple Access/Collision Detection. The access
method used in Ethernet. When a device wants to gain access to
the network, it checks to see if the network is quiet (senses the
carrier). If it is not, it waits a random amount of time before
retrying. If the network is quiet and two devices access the line
at exactly the same time, their signals collide. When the
collision is detected, they both back off and each waits a
random amount of time before retrying.
determinism The ability to predict when information will be delivered.
Important in time critical applications.
DHCP The Dynamic Host Configuration Protocol (DHCP) is an Internet
protocol, similar to BootP, for automating the configuration of
computers that use TCP/IP. DHCP can be used to automatically
assign IP addresses, to deliver TCP/IP stack configuration
parameters such as the subnet mask and default router, and to
provide other configuration information such as the addresses
for printer, time and news servers.
DNS The Domain Name System (DNS) is a hierarchical, distributed
method of organizing the name space of the Internet. The DNS
administratively groups hosts into a hierarchy of authority that
allows addressing and other information to be widely distributed
and maintained. A big advantage to the DNS is that using it
eliminates dependence on a centrally-maintained file that maps
host names to addresses.
Ethernet A physical layer standard using Carrier Sense Multiple Access with
Collision Detection (CSMA/CD) methods.