Page 103 - Optical Switching And Networking Handbook

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88 Chapter 4

Table 4-2
Electrical Rate Optical Rate Speed
Comparison of
STS-1 STM-0 51.84 Mbps
STS and STM
Rates STS-3 STM-1 155.52 Mbps

STS-9 STM-3 466.56 Mbps
STS-12 STM-4 622.08 Mbps

STS-18 STM-6 933.12 Mbps
STS-24 STM-8 1.244 Gbps

STS-36 STM-12 1.866 Gbps
STS-48 STM-16 2.488 Gbps

Table 4-3
STM Level Data Rate Actual Payload
SDH Payload
Compositions for 1 155.52 Mbps 150.112 Mbps
Hierarchical Rates 4 622.08 Mbps 601.344 Mbps

16 2.4883 Gbps 2.40537 Gbps

Some Differences to Note

Many of the actual rates in use are defined under the initial capaci-
ties of SONET in the CCITT standards. The original SDH standard
defined the transport of 1.5, 2, 6, 34, 45, and 140 Mbps within the
transmission rate of 155.52 Mbps (STM-1). SDH was intended to
carry the SONET rates; however, the European manufacturers and
carriers carry only the European Telecommunication Standards
Institute (ETSI)-defined PDH rates of 2, 34, and 140 Mbps (the E-2
specification was deleted in the specification). SDH really turns out
to be more than just a set of multiplexing speeds and transport rates.
It is also a network node interface (NNI) defined by the ITU-TSS for
worldwide use that is partially compatible with the ANSI SONET