
B-63644EN/02 APPENDIX C.ETHERNET-RELATED TERMINOLOGY
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C ETHERNET-RELATED TERMINOLOGY
This appendix briefly describes Ethernet-related terminology.
Note that this appendix describes only the minimum required
terminology. Refer to commercially available books for details.
TCP/IP
A protocol called "TCP/IP" (Transmission Control Protocol/Internet
Protocol) is generally used in communications using Ethernet. A
"protocol" refers to an arrangement or a set of rules for enabling
smooth communications between communications devices connected
via an electrical communications line. The TCP/IP protocol is part of a
layered structure comprising the following protocols and services.
Layer Protocols, Network Services
Application Layer User services as "FTP"
Transport Layer Protocols as "TCP", "UDP"
Network Layer Protocols as "IP", "ICMP"
Data Link Layer Protocols as "ARP", "RARP"
MAC Layer
Physical Layer Hardware as cables, devices
Usually, "TCP/IP" protocol is a generic name including the protocols
mounted on the two layers, transport layer and network layer, in the
above table.
IP address (INET address)
TCP/IP uses an address called an IP address (INET address) for
identifying a specified communications device among many
communications devices that are connected by Ethernet. To carry out
communications using TCP/IP, a unique IP address must be set to each
of the communications devices that are connected by Ethernet.
An IP address is an address that is four octets (bytes) long. Normally, it
is expressed in the form of four 8-bit fields (1 octet, 1 byte) each
delimited by a period. Each of these octets are capable of having a
value within the range 0 to 255.
IP addresses comprise a network address to which the communications
device is connected and the host address of that communications device.
IP addresses can be divided into three network classes, Classes A, B or
C, depending on the size of the network group.