HC900 Hybrid Controller Installation and User Guide

Components and Architecture - Networking Basics Reference
28 HC900 Hybrid Controller Installation and User Guide Revision 5
9/03
Name/Acronym Name/Definition Comments
Collision
Simultaneous transmission
of two nodes on the same
channel.
Collisions can be reduced (and network capacity
increased) by use of Switches, which partition and
isolate collision domains.
Collision
Detection
An indication to the Data
Link Layer that node
contention (simultaneous
transmission) is present at
the Physical Layer.
Collision Detection causes both nodes to abort
transmission, set a random delay, and attempt re-
transmission. If contention recurs, each device
doubles delay time before re-transmission;
successive redoubling is called “exponential back-
off”.
Crosstalk
Electrical noise coupled
between media elements
Cross-over Cable
Ethernet cable that enables
connection of DCE to DCE
equipment, or DTE to DTE
equipment.
In a "cross-over" cable, wiring crosses over from
the Transmit connection pair at one end to Receive
connection pair at the other end.
CSMA/CD
Carrier Sense Multiple
Access w/ Collision
Detection
All nodes on the same network are free to initiate
message transmission. If two nodes transmit
simultaneously, the collision is detected, and both
nodes abort transmission and attempt to re-transmit
after a pause.
CSU/DSU
Channel Service Unit/Data
Service Unit
Converts data from format used by telephone
company to format usable on LAN.
Cut-Through
Method used by switches
for filtering messages, based
on the first few bytes.
Enhances transmission speed, but reduces
transmission security and/or reliability.
Data Link
A logical connection
between two nodes on a
network.
Data Link Layer
Layer 2 of the OSI Model
that is media-independent,
and functions above Layer 1
(Physical Layer).
Defines protocols for data packets and how they
are transmitted between networking devices.
Includes two sublayers: Media Access Control
(MAC), and Logical-Link Control (LLC).
Datagram
A series of bits in an
ordered, intelligible
sequence.
Datagrams are commonly referred to as “Packets”,
because they are data entities, although Packets
apply only the top layer (Application Layer of the
OSI Model.
DCE
Data Communications
Equipment
Devices that transport data between DTE devices.
DHCP
Dynamic Host
Configuration Protocol
Runs in a DHCP server, which assigns an IP
address to each node that connects to the network.
(Can not be used in a an HC900 LAN.)
DNS Domain Name System
An Internet system (resident in a Web Browser)
that resolves domain names to IP addresses. (For
example, Http://www.yahoo.com
resolves to
Http://204.71.202.160.
)
Domain
On the Internet, a named
network.
In MS Windows, an
elemental administrative
(security-oriented) unit.
User Names/Passwords, and related data on a
network.