Specifications

Ethernet Devices 6-5
Ethernet Bridges
Multi-port Repeaters
A multi-port repeater is a device which has more than two ports that
connect to full-length Ethernet Segments. Generally the repeaters are very
similar in appearance to the two-port local repeater shown in Figure 6-5,
with the exception of the number of ports. These repeaters regenerate the
preamble and amplify and re-time a signal from one cable segment to the
others.
Inter-Repeater Links (IRLs)
Up to 3 repeaters can be used to connect separate coaxial segments before
special considerations need to be taken into account. If the segments are
physically located a distance from each other, the use of an Inter-Repeater
Link (IRL) comes into play. As shown in Figure 6-6, an IRL is a segment
that connects only two repeaters. It can be made up of thin coaxial cable
(185 m), thick coaxial cable (500 m), twisted pair cable (200 m), or Fiber
optic cable (2/5 km). With the use of IRLs it is possible to build a network
consisting of up to three populated segments with two IRLs and four
repeaters joining them.
Figure 6-6. Using an IRL
Ethernet Bridges
A bridge is a device that can be added to a network to allow expansion
beyond the limitations of 802.3. If a network has a repeater hop of four
repeaters or a propagation delay near the 51.2 µs maximum, a bridge can
be used to accomplish the addition of the new full specification Ethernet.
Inter Repeater Link
NETWORK 1
(Up to 1,024 devices)
NETWORK 2
(Up to 1,024 devices)
Repeaters
(length dependent
on media type)
1913-17