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OPTICAL PACKET SWITCHING

Explore the technology of optical packet switching, combining benefits of circuit and packet switching for efficient data transfer over optic fibers. Learn about architecture, limitations, solutions, and future trends in this advanced network system.

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OPTICAL PACKET SWITCHING

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  1. OPTICAL PACKET SWITCHING Done by : ARUN JOY R7A11

  2. WHAT IS A SWITCH ?? • Device that channels incoming data from any of the multiple input ports to any of the output ports. • SWITCHING TYPES • CIRCUIT SWITCHING • PACKET SWITCHING • In circuit switching a dedicated path is established for communication. E.g.: telephone networks • In packet switching, the messages to be transmitted is broken to small PACKETS.

  3. Today’s switching networks • ROUTING and TRANSMISSION are the two functions required to move packets through networks • The router uses the information in the packet-(IP header, Type, Priority) to route the packets from input to output with minimal packet loss

  4. Optic fibers • A medium for transmitting information in the form of light pulses along a glass/fiber • Also known as LIGHT PIPE • Provides greater bandwidth

  5. WAVE LENGTH DIVISION MULTIPLEXING (WDM) • A technology used to increase the information rate • Here multiple signals can traverse through a single strand of optic fiber

  6. USE • By the use of this technology, optic fiber transmission system can carry 32-80 wavelengths modulated @ 2.5gbps-10gbps per wavelength

  7. OPTICAL TRANSMISSION MEDIA • In MAN, links between the nodes are optical fibers • Here packets are in the optical format • O-E-O conversion are required at the interface

  8. LIMITATIONS • LIMITED PACKET PROCESSING • SLOW OPERATION • COST AND COMPLEXITY • CROSS TALK These limitations degrades the performance of the system affecting the bandwidth

  9. SOLUTION! • The solution is OPTICAL PACKET SWITCHING • The signals are being processed by means of OPTICAL SWITCH FABRIC OPTICAL SWITCH FABRIC OPTICAL SIGNALS OPTICAL SIGNALS

  10. SWITCH ARCHITECTURE • An OPS node consists of following components • INPUT INTERFACE • SWITCHING MATRIX • BUFFER • OUTPUT INTERFACE • 5. ELECTRONIC CONTROL UNIT

  11. 1.INPUT INTERFACE • Wave length conversion ->conversion of external to internal wavelengths ->identification of the beginning and end of the header and payload • Provides synchronization • Header processing

  12. CONTROL UNIT • Processing routing information • Updates header information • Forwards header to output interface

  13. SWITCHING MATRIX • Optical switching of the payloads according to the commands from the control unit

  14. OUTPUT INTERFACE • Provides 3R(reamplification,reshaping,retiming) regeneration • Attaches updated header to corresponding optical payload • Conversion of internal to external wavelength • resynchronization

  15. GENERAL PACKET FORMAT • A generic packet format consists of • Header • Payload • Additional GUARD BANDS before and after payload

  16. PACKET HEADER • A packet header may comprise of following fields • Sync-provides synchronization • Source Label-provides source node address • Destination Label-provides destination node address • Type-type and priority of the carried payload

  17. continued… • Sequence Number:Packet sequence number to reorder packets arriving out of order and guarantee in-order packet delivery • OAM: Operation, Administration, Maintenance • HEC: Head Error Correction

  18. OPTICAL SWITCHING TECHNIQUES • Two types of optical switching techniques 1.ALL OPTICAL LABEL SWAPPING (AOLS) 2.LIQUID CRYSTAL SWITCHES

  19. ALL OPTICAL LABEL SWAPPING • Consists of Optical Core Networks 1.Edge Router 2.Core Router • Here Packets can be routed independent of Payload Bit Rate, Coding format ,length etc • Can handle IP packets as well as ATM cells

  20. LABEL • A Lower Bit Rate (LABEL) is attached to the front of the packet • A LABEL contains- 1.Error checking information 2. Source Information 3. Destination Information 4. Framing and timing information

  21. PROCESS • Packets entered through EDGE nodes (source side) is encapsulated with the optical label • Header is removed. • At internal CORE nodes, the label is optically erased, embedded with a new label • The payloads with the label gets routed in the networks • At the Edge nodes (destination side) ,the label is Erased back to packet payload • Updated header is encapsulated to the payload

  22. All optical label swapping

  23. 2.LIQUID CRYSTAL SWITCHES • Principle : -when an electric field is applied to liquid crystal, the molecules line up and become opaque • The molecules are so thin and straight, will allow light of a particular orientation to pass through the liquid crystal • It consists of 2 components • CELL • DISPLACER

  24. CELL AND DISPLACER CELL: Formed by placing the liquid crystal between 2 plates of glass Glass is coated with oxide materials that conducts electricity The function is to REORIENT the polarized light entering the cell DISPLACER: It is a composite crystal that directs the polarized light leaving the cell

  25. conclusion • The new technology –regarded as ULTIMATE SOLUTION to bandwidth needs PROVIDING ->IMPROVED EFFICIENCY ->LOW COSTS ->UTILISE DWDM

  26. THANK YOU!!!

  27. QUESTIONS ????

  28. DONE BY • ARUN JOY • 7TH SEMESTER,DEPARTMENT OF COMPUTER SCIENCE AND ENGG, SREE NARAYANA GURUKULAM COLLAGE OF ENGINEERING,KADAYIRUPPU.

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