The Ethernet Buzzword Guide

Ethernet has a zillion buzzwords and plenty of strange abbreviations, acronyms and “short hand” –
for example, “10BASE-T” means 10 megabits per second, baseband, Twisted Pair. This guide is a
collection of the most common terms that you encounter when you’re working with Ethernet and TCP/IP.
1000BASE-CX Gigabit Ethernet on twinax copper cabling
Gigabit Ethernet for vertical or campus backbones; single or multimode fiber
Gigabit Ethernet for low cost, short backbone, or horizontal
100BASE-T Standard "Fast Ethernet" based on twisted pair copper wire
10BASE2 Old "Cheapernet" with thin coaxial cable and trunk/drop topology
10BASE5 Old "Thicknet" with thick coaxial cable and trunk/drop topology
10BASE-FL 10Mbps fiber optic Ethernet
Standard "Plain Vanilla" Ethernet based on Unshielded Twisted
Pair wire
7 Layer Networking
Concept of viewing data in layers: physical, data link, network,
transport, session, presentation and application
Application Layer
The layer of information that gives meaning to transmitted data
ARP Protocol
Address Resolution Protocol - translates TCP/IP addresses to
physical MAC addresses
Auto-Negotiation Hardware feature for automatic adjustment to proper bit rate
Bridging Router
Router that automatically forwards a message it doesn't
Classless Subnet Masks
Block of IP addresses with specified notation to indicate how many
bits are within a subnet (e.g.
Crossover Cable
Cable with transmit/receive pairs reversed so one hub or switch
can link directly to another
Carrier Sense Multiple Access Collision Detection - arbitration
mechanism for competing Ethernet messages
Dynamic Host Configuration Protocol - permits auto-assignment of
temporary IP addresses for new devices logging in
DNS Domain Name Server - associates names with IP addresses
Duplex Communication travelling between two nodes in both directions
Application layer protocol based on (Control and Information
Protocol) from Devicenet/ControlNet
Flow Control
Mechanism used by switches & routers to regulate receipt of
heavy traffic loads
Foundation Fieldbus HSE
High Speed Ethernet (100Mbps) implementation of the Foundation
Fieldbus protocol for process control
File Transfer Protocol - the most popular mechanism for bulk
movement of files on TCP/IP
Full Duplex
Messages can be sent and received between two nodes
Device which links Ethernet to dissimilar networks and transfers
data at the application layer level
Half Duplex
Two nodes can send and receive messages with each other, but
only one at a time
Repeater which indiscriminately broadcasts messages to all
connected nodes
Industrial Ethernet
IEEE 802.3 Ethernet and TCP/IP with provisions for harsh physical
and electrical conditions
IP Address
Address of a TCP/IP enabled device on an Intranet or Internet - in
the form
IP Protocol Internet Protocol portion of TCP/IP
IP v.4 The current version of the IP protocol, uses 32 bit addresses
IP v.6
New version of the IP protocol with provisions for 128 bit
addresses and advanced broadcast features
LAN Local Area Network
Media Access Control - the physical components which
disassemble Ethernet message fames
MAC Address The physical address of an Ethernet node
Transformer which provides voltage isolation and protection for
Ethernet hardware
Managed Hub
Hub which can be externally programmed to accept / reject
specific types of messages
Network topology in which messages can use a variety of routes to
reach a destination
Application layer protocol for automation based on Modbus
Utility that reports active TCP connections, state of servers &
sockets, and IP routing tables in use
Physical component which decodes data and produces signal
levels that drive magnetics and cable
Packet Inter Net Groper - very useful utility which probes for the
existence of a TCP/IP host
A number in TCP/IP to which services are assigned; e.g. FTP is
port 21; SMTP is port 25; HTTP is port 80.
PROFINet Application layer protocol from Profibus Trade Organization
Private IP Addresses
Range of IP addresses not recognized by Internet routers,
designated for private LANs
Protocol Agreed-upon format for transmitting or storing data
Repeater Buffer which cleans up, strengthens and re-transmits a signal
Repeater which selectively re-distributes messages based on IP
Serial Server Device which converts serial data to Ethernet
Communication between two devices that can only travel in one
Simple Network Management Protocol; allows monitoring and
management of a network
Specific instance of an IP address and Port number that
represents a single connection between two applications
Star Topology
Topology which allows only one device at each end of a wire and
requires repeaters for more than two devices
Repeater which selectively re-distributes messages based on
hardware MAC address
TCP Protocol
Transmission Control Protocol - mechanism in TCP/IP that
ensures that data arrives intact and in correct order
Transmission Control Protocol / Internet Protocol - an entire suite
of protocols and delivery mechanisms for Internet data
Standard interface through which a client may access a host as
though it were local
Topology Physical format of a network
Utility which tells which routers / servers exist between a source
and destination
Trunk/Drop Topology Topology which allows many devices on one cable
Twisted Pair Standard wire format for Ethernet cables
User Datagram Protocol - lower overhead alternative to TCP
protocol which does not guarantee message delivery
For further information…
  • Check out our extensive series of application notes, articles and guides at
  • Industrial Ethernet: A Pocket Guide by Perry S. Marshall, ISA Press
  • Practical TCP/IP & Ethernet Networking for Engineers and Technicians by Deon Reynders and Edwin Wright, IDC Techbooks,
  • Ethernet: The Definitive Guide by Charles E. Spurgeon, O’Reilly Press