1.4 Digital Multiplexing Techniques
17
Table 1.6 Common SDH and SONET line rates and their popular numerical name
SONET level
Electrical level
SDH level
Line rate (Mb/s)
Popular rate name
OC-1
STS-1
–
51.84
–
OC-3
STS-3
STM-1
155.52
155 Mb/s
OC-12
STS-12
STM-4
622.08
622 Mb/s
OC-48
STS-48
STM-16
2488.32
2.5 Gb/s
OC-192
STS-192
STM-64
9953.28
10 Gb/s
OC-768
STS-768
STM-256
39,813.12
40 Gb/s
that of an OC-1 signal. For SDH systems the fundamental building block is the
155.52 Mb/s Synchronous Transport Module—Level 1 (STM-1). Again, higherrate information streams are generated by synchronously multiplexing N different
STM-1 signals to form the STM-N signal. Table 1.6 shows commonly used SDH
and SONET signal levels, the line rate, and the popular numerical name for that
rate. Note that although SONET rates can be defined for data rates beyond 40 Gb/s,
emerging requirements for efficient transport of information from high bandwidth
data services requires a new technology such as Sect. 1.4.3 describes.
1.4.3 Optical Transport Network (OTN)
In the early days of telecommunications, for decades network traffic consisted principally of voice calls that were transported over networks in which the connections
between endpoints followed a predictable connection scheme. When data services
emerged, adaptations were developed to map the data traffic onto SONET/SDH
networks to provide a single transport network. However, this scheme became
increasingly difficult to implement beyond 40 Gb/s because voice and data have
inherently different transport requirements. Whereas aggregated voice traffic follows
a predictable connection pattern, data services and applications have bursty, unpredictable traffic patterns with widely varying demands on bandwidth and data transmission performance. Consequently, the telecom industry developed a new technology known as the Optical Transport Network for transmission rates of 40 Gb/s
and above. The ITU has standardized OTN as G.709. Chapter 13 gives more details
on OTN and its applications.
1.5 Multiplexing of Wavelength Channels
The burgeoning development of consumer equipment such as powerful laptop PCs,
tablet computers, 4G and 5G smart phones, high-definition TV sets, and control
17
Table 1.6 Common SDH and SONET line rates and their popular numerical name
SONET level
Electrical level
SDH level
Line rate (Mb/s)
Popular rate name
OC-1
STS-1
–
51.84
–
OC-3
STS-3
STM-1
155.52
155 Mb/s
OC-12
STS-12
STM-4
622.08
622 Mb/s
OC-48
STS-48
STM-16
2488.32
2.5 Gb/s
OC-192
STS-192
STM-64
9953.28
10 Gb/s
OC-768
STS-768
STM-256
39,813.12
40 Gb/s
that of an OC-1 signal. For SDH systems the fundamental building block is the
155.52 Mb/s Synchronous Transport Module—Level 1 (STM-1). Again, higherrate information streams are generated by synchronously multiplexing N different
STM-1 signals to form the STM-N signal. Table 1.6 shows commonly used SDH
and SONET signal levels, the line rate, and the popular numerical name for that
rate. Note that although SONET rates can be defined for data rates beyond 40 Gb/s,
emerging requirements for efficient transport of information from high bandwidth
data services requires a new technology such as Sect. 1.4.3 describes.
1.4.3 Optical Transport Network (OTN)
In the early days of telecommunications, for decades network traffic consisted principally of voice calls that were transported over networks in which the connections
between endpoints followed a predictable connection scheme. When data services
emerged, adaptations were developed to map the data traffic onto SONET/SDH
networks to provide a single transport network. However, this scheme became
increasingly difficult to implement beyond 40 Gb/s because voice and data have
inherently different transport requirements. Whereas aggregated voice traffic follows
a predictable connection pattern, data services and applications have bursty, unpredictable traffic patterns with widely varying demands on bandwidth and data transmission performance. Consequently, the telecom industry developed a new technology known as the Optical Transport Network for transmission rates of 40 Gb/s
and above. The ITU has standardized OTN as G.709. Chapter 13 gives more details
on OTN and its applications.
1.5 Multiplexing of Wavelength Channels
The burgeoning development of consumer equipment such as powerful laptop PCs,
tablet computers, 4G and 5G smart phones, high-definition TV sets, and control