PRESENTATION BY SRIDHARSAN T P SONET PRESENTATION BY SRIDHARSAN T P

STRUCTURE SUMMARY OPTICAL NETWORKING HISTORY SERIAL COMMUNICATION ASYNCHRONOUS AND SYNCHRONOUS PDH TECNOLOGY BLOCK DIAGRUM PULSE CODE MODULATION LIMITATIONS OF PDH SONET ACHIEVEMENTS FEATURES BLOCK DIAGRUM LAYERS FRAME MERITS SUMMARY

OPTICAL NETWORKING Optical networking is a means of communication that uses signals encoded onto light to transmit information among various nodes of a telecommunications network. TECHNOLOGY TRANSMITTERS RECIEVERS FIBRE OPTIC CABLE AMPLIFIERS WAVELENGTH DIVISION MULTIPLEXING

HISTORY 1880 – PHOTOPHONE by Alexander Graham Bell and Charles Summer. 1954 – USING GLASS ROD by Harold Hopkins Narinder Singh Kapany. 1966 – COMPARISSON Between Glass Rod and Coaxial cable, Electricity and Light by  Charles K. Kao and George Hockham. 1970 – OPTICAL FIBRE DEVOLOPPED by  Corning Glass Works ( attenuation about 20 dB/km). 1975 – COMMERCIAL IMPLIMENTATION (45Mbit/s)

SERIAL COMMUNICATION

ASYNCHRONOUS COMMUNICATION Total 10 bits (8 bit data + 2 bit parity) Gap between bytes Slow No clock signal required Economical Applicable in bit level communication Example : Keyboard, Mouse

SYNCHRONOUS COMMUNICATION Transmit block of data and bit streams No gap between bytes Faster Transmitter and reciever are synchronised Reciever counts bits and generate bytes Accuracy is depends on the counting

PLESIOCHRONOUS DIGITAL HEIRARCHY Plesios – near, Chronos – time Almost synchronoused PDH allows transmission of data streams that are nominally running at the same rate, but allowing some variation on the speed around a nominal rate. This means that different data streams can (and probably do).  run at slightly different rates from one another. Bit stuffing technology is used Have two standards North America (Designed as DS0) Europe (designated as E0)

BLOCK DIAGRUM

PULSE CODE MODULATION (PCM) Method to convert analog signal to digital signal The word pulse refers to pulses found in transmission lines PCM is in binary form  Two possible states high and low(0 and 1) We can also get back our analog signal by demodulation Have include three steps Sampling Quantization Coding

LIMITATIONS OF PDH Different frame is used for transmission and in data layer, Hence multiplexing and de-multiplexing is very complex. The maximum capacity for PDH is 566 Mbps, which is limited in Bandwidth. PDH allows only Point-to-Point configuration PDH does not support Hub.  Every manufacturer has its own standards; PDH also has different multiplexing hierarchies making it difficult to integrate interconnecting networks together.  

SYNCHRONOUS OPTICAL NETWORKING ACHIEVEMENTS Standard multiplexing using multiples of 51.84 Mbps (STS-1 & STS-N) as building blocks Optical signal standard for interconnecting multiple vendor equipment Multiplexing formats for existing digital signals (DS1,DS2 etc) Supports ITU hierarchy (E1 etc) Allows quick recovery from failure

FEATURES First standardized by ANSI, now SDH by ITU-T SONET is time division multiplexing SONET encompasses optical and electrical specification SONET uses octet multiplexing SONET uses extremely precise timing Provides support for operation, maintenance and administration (OAM)

BLOCK DIAGRUM

STS MULTIPLEXER Multiplexes and de-multiplexes signals from multiple sources Path terminating equipment Maps user payload into standard frame Header goes end-to-end as part of Synchronous Payload Envelope – SPE

ADD/DROP MULTIPLEXER Adds signals from different sources/removes Uses header address information to identify stream and remove Line terminating Equipment Performs multiplexing, synchronization

Frame alignment, Error detecting Section terminating equipment REGENERATOR Repeater – improves signal quality Operations – include layer 2 Frame alignment, Error detecting Section terminating equipment

ABOUT THE BLOCK DIAGRUM SECTION Connects two neighboring devices LINE Connects two multiplexers PATH Connects two STS MUX and DEMUX

SONET LAYERS

SONET FRAME STS-1 FRAME

SONET FRAME VALUES

MERITS OF SONET A more simplified multiplexing and demultiplexing technique. Synchronous networking and SDH supports multipoint networking. Capability of transporting existing PDH signals It is multivendor and supports different operators It allows quick recovery from failure  Switching protection to traffic is offered by rings

SUMMARY A carrier system – optical carriers Synchronous transmission - faster Time Division multiplexing High speed backbone Support for high bit rate applications Add/Drop multiplexers Self healing rings

THANKS