1. Fiber Optic Communication By
Engr. Muhammad Ashraf Bhutta

2. History of SONET Digital carrier systems
The hierarchy of digital signals that the telephone network uses.
Trunks and access links organized in DS (digital signal) hierarchy
Problem: rates are not multiples of each other.
Telco's needed to replace aging copper wire networks
Telco's wanted a global standard to connect a fiber optic network
SONET first proposed by Bellcore, in 1984
Synchronous Digital Hierarchy (SDH) was used in Europe
Agreement was made in 1998 to merge the two similar standards

3. SONET Protocol Hierarchy

19. STS-1 Building BLock

20. STS-1 Building BLock Basic building block of SONET
Rate 51.84Mbps usually depicted 9 rows X 90 columns = 810 8bit bytes
With a rate of 8000 frames/sec. Each frame has a duration of 125 microseconds.
At 6480 bits per frame x, 8000 frames a second equals 51,840,000bps or 51.84Mbps

21. SONET Cell Mapping

22. SONET Topologies Point-to-Point 2 devices connected by optical fiber
Entry level PTE for an organization
Inputs/Outputs identical

23. SONET Topologies Point-to-Multipoint
Uses Add-Drop Multiplexing (ADM) to drop circuits off along the way
Suitable for large national corporate networks

24. SONET Topologies Hub & Spoke
Accommodates unexpected growth or change more easily than point-to-point
Hub concentrates traffic at a central site to allow for easy reprovisioning of the circuits

25. SONET Topologies
Ring
ADM is building block for SONET ring architecture.
Multiple ADMs within a ring topology can either be bidirecitonal or unidirectional
Main advantage is survivability - if a fiber cable is cut, the multiplexers have the intelligence send via an alternative path through the ring without interruption

26. SONET Ring
DCC
ADM

27. 9 columns x 9 rows = 81 octet section overheads
Synchronous Digital Hierarchy (SDH)
European Standard analogous to the North American SONET
Basic building block is the STM-1 Frame that consists of:
270 columns x 9 rows = 2430 octets
9 columns x 9 rows = 81 octet section overheads
Will be discussed in next lecture( )

28. SONET over WDM SONET Wavelength Division Multiplexing (WDM)
Single wavelength optical network.
Uses fiber as transmission media,
Does all switching, routing, processing electronically.
Wavelength Division Multiplexing (WDM)
Wavelength routing
Carry multiple wavelengths in a single fiber

29. SONET over WDM
WADM λ3 λ1
Complete it?

30. Plesiochronous Transmission
Means “almost synchronous”
Bits are stuffed into the frame as padding when various occur on the timing of the line
Factors that affect transmission rates over fiber optic lines:
Temperature differences along the cable can affect light signaling and clock timing
Photonic and Laser technology is a limiting factor in the evolution of higher data rates over SONET

31. Benefits of SONET Pointers, MUX/DEMUX
SONET allows very flexible allocation and alignment of payload within transmission envelop.
Reduced Back-to-Back Multiplexing
Because of synchronization, an entire optical signal does not have to be demultiplexed – only the VT or STS signals need to be accessed.
Optical Interconnectivity
Allows interconnection between network providers regardless of equipment manufacturer.

32. Benefits of SONET Multipoint Configurations ATM Grooming
Network providers no longer need to own and maintain customer-located equipment
ATM
Because of the bandwidth capacity offered by SONET, it is a logical carrier for ATM
Grooming
SONET networks can eliminate inefficient techniques like back-hauling, which is expensive to do on asynchronous systems
SONET can also conveniently segregate switched and non-switched traffic.

33. Benefits of SONET Reduced Cabling & Elimination of DSX Panels
SONET allows for hub configuration, reducing the need for back-to-back terminals
Enhanced OAM&P
Remote positioning provides centralized maintenance, reduced travel for maintenance personnel, hence reduced savings.
Enhanced Performance Monitoring
SONET allows for quicker troubleshooting and detection of failures before they because of the substantial overhead information.