Toshiba CIEMAC-DS, Инструкция по эксплуатации

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Appendix
18
Cable segments and link segments
There are two types of segments as defined in the IEEE802.3 standard: cable segments and link segments.
The differences affect the constraints for expanding transmission lines. This section describes the
differences between these segments.
Cable segment
Consists of a set of coaxial cables whose ends are terminated with characteristic impedance. A
transceiver is attached to this segment to connect a station. This is also called as a coaxial segment.
Link segment
A point-to-point connection cable with repeaters (or transceivers) at both ends. No station is connected.
In the TOSDIC-CIE DS system, this refers to the following three types of segments.
- An optical fiber cable with optical repeaters connected at both ends.
- A coaxial cable with electric repeaters connected at both ends, with no station connected.
- A twisted pair cable that connect a hub and station on 10BASE-T (a hub is a kind of repeater).
Maximum network configuration
The "Constraints for expanding transmission lines" are often summarized and referred to as the "5,4,3 rule".
"5 segments/4 repeaters/3 cable segments"
(Up to 5 segments, 4 repeaters, and 3 cable segments)
Some examples of network configuration under this rule are shown below.
TR TR TR TR TR TR TR TR TR TR TR
RP RP RP RP
Station
500m 500m 500m 500m 500m
Link
Segment Link
Segment Cable
Segment Cable
Segment Cable
Segment
Stations cannot
be connected Stations cannot
be connected
Maximum 2500m
Station
Station
Figure 1.1 An Example of Network Configuration with Coaxial Cables Only