BXM T3/E3, 155, and 622 6-27
General SONET Notes
• IEC 801-2, EN55022
• Safety: EN 60950, UL 1950
• Bellcore NEBS:Level 3 compliant
• Optical Safety:
— Intermediate Reach IEC 825-1 (Class 1)
— Long Reach IEC 825-1 (Class 36)
General SONET Notes
SONET is defined across three elements, section, line, and path as shown in Figure 6-13 and
described in Table 6-10. An advantage of this tiered approach is that management control can be
exercised at each level, for example at the section level independent of the line or path level.
Figure 6-13 SONET Section, Line, and Path
Table 6-11 provides a cross-reference between OC-n optical carrier levels and the equivalent STS-n
and SDH-n levels. It also includes the associated line rates.
Table 6-10 SONET Section, Line, and Path Descriptions
Unit Description
Section A section is the fiber optic cable between two active elements such as simple repeaters. The active
element terminating these sections is called Section Terminating Equipment (STE).
Line A line is a physical element that contains multiple sections and repeaters and is terminated by line
terminating equipment (LTE) at each end.
Path A path includes sections and lines and terminates at the customer premises equipment (CPE).
Table 6-11 Digital Hierarchies
OC-n
Optical Carrier
STS-n
Synchronized
Transport Signal
Line Rates
(Mbps)
SDH-n
Synchronized
Digital Hierarchy
STM-n
Synchronous
Transport
Module
OC-1 STS-1 51.84
OC-3 STS-3 155.52 SDH-1 STM-1
OC-12 STS-12 622.08 SDH-4 STM-4
OC-48 STS-48 2488.32 SDH-16 STM-12
Section
CPE
CPE
Switch
LTE
Switch
LTE
STE STE
Section
Line
Path
12196
Section
