Synchronous Optical Network

[seminar class]

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Synchronous Optical Network / Synchronous Digital Hierarchy
Optical Networks
► Faster than conventional networks because of photons (low weigh than electrons, no charge hence do not interfere with other)
► WDM/DWDM Networks
► Prior to development of Synchronous Optical Networks (SONET) and Synchronous Digital Hierarchy (SDH), optical network solution in WAN were:
► Vendor specific
► Haphazard in data support
► Without clear migration paths
► With the invention of SONET/SDH,
► all such problems solved
► Vendor interoperability established up to certain extent
► SONET/SDH
► Initially used for voice communication
► But with the arrival of Internet, it play the important role in transmission of IP packets and others
Issue with SONET/SDH
► Single Wavelength Technology
► 1.31 mm
► No Wavelength Division Multiplexing
Hence, at a time only one data stream transmission is possible
► At the time of its standardisation (1988), there was no such high demand for bandwidth
► Most of the network were voice centric
► As present/future networks are going to use multi-wavelength technologies such as WDM or DWDM:
 What will be the future of SONET/SDH?
What is SONET/SDH?
► Defines hierarchical set of transmission rates and transmission formats for optical fiber systems for networking applications
► SONET is
 Synchronous Optical Network
 Developed originally by client and standardized by ANSI
 For North America
► SDH is
 Synchronous Digital Hierarchy
 Developed by ITU-T (previously CCITT)
 For European and other Countries in the world