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 wavelengths 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.