Optical Circuit Switching vs Optical Burst Switching vs Optical Packet Switching | difference between Optical circuit Switching, Optical Burst Switching and Optical Packet Switching
This page compares Optical Circuit Switching vs Optical Burst Switching vs Optical Packet Switching and mentions difference between Optical circuit Switching, Optical Burst Switching and Optical Packet Switching. It mentions advantages and disadvantages of optical circuit switching, optical burst switching and optical packet switching types.
The figure-1 depicts evolution of optical switching techniques.
As shown it consists of following techniques.
• OCS-Optical Circuit Switching
• OBS-Optical Burst Switching
• OPS-Optical Packet Switching
➨Optical Circuit Switching adds additional functionalities to point to point WDM network.
WDM stands for Wavelength Division Multiplexing. Here switching occurs due to intermediate routers
between source and destination devices.
➨In Optical Burst Switching, bursts of data are switched optically instead of electronic switching. It does not use any buffers.
➨In Optical Packet Switching, packets are switched and buffered in the optical form before they are forwarded to the next hop in the network.
Optical Circuit Switching
• The figure-2 depicts optical circuit switching.
It works based on the principle of wavelength routing which
is based on dedicated wavelength being assigned for each path from source
to the destination.
• Once the connection is established, data will remain in optical domain (i.e. in light form) till it reaches to the destination.
• In this type circuit connection is established first between the devices before the communication begins.
• The connection can be fixed or created dynamically as needed. There may be many paths between source and destination but only one path as established is used for the communication as shown.
Advantages and Disadvantages of Optical Circuit Switching
Following are the advantages of Optical Circuit Switching:
• Supports natural QoS
• Commercially available for use
Following are the disadvantages of Optical Circuit Switching:
• high wavelength consumption
• Low flexibility
• lower network utilization
• large node size
Optical Burst Switching
• The figure-3 depicts optical burst switching. In this technique, client data will go through
burst assembly and burst disassembly at each edge of the network.
Here multiplexing occurs at burst level where in
IP packets are fragmented into smaller size bursts. This is done at
core of OBS network.
• Here data and control signals are transmitted on different wavelengths or channels. Hence O/E/O conversions are carried out on few control channels which saves cost to great extent. This is due to the fact that such conversions are being avoided on large number of channels.
Advantages and Disadvantages of Optical Burst Switching
Following are the advantages of Optical Burst Switching:
• High flexibility
• Efficient utilization of network
Following are the disadvantages of Optical Burst Switching:
• Effort for traffic aggregation is complex
• Resilience more complex
• control is complex
Optical Packet Switching
In optical packet switching technique, packet header is being processed either optically or electronically at each intermediate node. The Optical/Electronic (O/E) conversion and viceversa is done as required. The data payload waits in delay lines of the fiber before being forwarded to the next node. The figure-4 depicts optical packet format/structure. As shown it consists of packet train where in each individual packet consists of OGB (Optical Guard Band), header and synch data.
Advantages and Disadvantages of Optical Packet Switching
Following are the advantages of Optical Packet Switching:
• Reduced size of node
• very much flexible utilization of network
• very efficient network utilization
Following are the disadvantages of Optical Packet Switching:
• Higher control complexity
• requires more effort for the packet recording
Following table mentions difference between the three types viz.
|Specifications||Optical Circuit Switching||Optical Burst Switching||Optical Packet Switching|
|Data size||supports >GB of data size||supports 100 to 1500 Bytes||supports tens of kbytes|
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