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CTI 2572 Technical Overview Manual
10
3.2 Ethernet Topologies and Media - Physical Layer
Ethernet Version 2 and IEEE 802.3 are fully compatible at the physical level. Therefore the
formal IEEE 802.3 specification is used to describe all Ethernet media. The 802.3 specification
provides for a variety of topologies and media. All commonly used media operate at 10 Mb.
Specified media/topology can be used interchangeably and can be intermixed on the same
network. Ethernet media specifications include "thick" coax (10Base5), "thin" coax (10Base2),
twisted pair (10BaseT), and Fiber Optics (FOIRL). The specification provides for a media
independent port on Ethernet adapter cards known as an Attachment Unit Interface (AUI).
Media specific transceivers attach to the AUI. In addition most adapters provide at least one
native media attachment (usually 10Base2 or 10BaseT).
formal IEEE 802.3 specification is used to describe all Ethernet media. The 802.3 specification
provides for a variety of topologies and media. All commonly used media operate at 10 Mb.
Specified media/topology can be used interchangeably and can be intermixed on the same
network. Ethernet media specifications include "thick" coax (10Base5), "thin" coax (10Base2),
twisted pair (10BaseT), and Fiber Optics (FOIRL). The specification provides for a media
independent port on Ethernet adapter cards known as an Attachment Unit Interface (AUI).
Media specific transceivers attach to the AUI. In addition most adapters provide at least one
native media attachment (usually 10Base2 or 10BaseT).
10Base5 "Thick" Coax
10Base5 was the original Ethernet media.
It is capable of cable runs up to 500 meters
(approximately 1500 feet). This distance
may be extended by the use of a repeater.
Ethernet stations (nodes) are attached to
the 10Base5 cable in a tap fashion. The
transceivers are mounted on the cable and
a cable is run from the transceiver to the
AUI port on the adapter. Although there
are numerous installations in place using
10Base5 cabling, new installations tend to
use other, more cost effective, cabling
media.
It is capable of cable runs up to 500 meters
(approximately 1500 feet). This distance
may be extended by the use of a repeater.
Ethernet stations (nodes) are attached to
the 10Base5 cable in a tap fashion. The
transceivers are mounted on the cable and
a cable is run from the transceiver to the
AUI port on the adapter. Although there
are numerous installations in place using
10Base5 cabling, new installations tend to
use other, more cost effective, cabling
media.
10Base2 "Thin" Coax
10Base2 coax has been a popular media
for Ethernet installations. It is capable of
cable runs up to 200 meters (about 600
feet). This distance may be extended by
using a repeater. The standard uses a 50
ohm coaxial cable and standard BNC
connectors, both widely available and
relatively inexpensive. In fact 10Base2 is
often referred to as "cheapernet" due to
this low cost. 10Base2 cabling uses a "T"
connector at each tap with a 50 ohm terminator at each end. The "T" connector may be attached
to a 10Base2 transceiver (and the network adapter card via the AUI port). Alternately, the
network adapter may provide a direct attachment for 10BaseT.
for Ethernet installations. It is capable of
cable runs up to 200 meters (about 600
feet). This distance may be extended by
using a repeater. The standard uses a 50
ohm coaxial cable and standard BNC
connectors, both widely available and
relatively inexpensive. In fact 10Base2 is
often referred to as "cheapernet" due to
this low cost. 10Base2 cabling uses a "T"
connector at each tap with a 50 ohm terminator at each end. The "T" connector may be attached
to a 10Base2 transceiver (and the network adapter card via the AUI port). Alternately, the
network adapter may provide a direct attachment for 10BaseT.
Transceiver
Transceiver
Transceiver
Ethernet
Station
AUI Port
Ethernet
Station
AUI Port
Ethernet
Station
AUI Port
10Base5 (Thick Coax)
Figure 4 10Base5 (Thick Coax) Topology
-
-
Transceiver
Station
AUI Port
Transceiver
Station
AUI Port
10Base2 Port
Station
10Base2 (Thin Coax)
Figure 5 10Base2 (Thin Coax) Topology