Allen-Bradley ControlLogix 1756-ENBT, User Manual

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1 Publication 1756-UM050A-EN-P - December 2001
Glossary
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 1756-ENBT 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
A 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.
AB Parts