Banyan switch
Encyclopedia
In electronics
, a banyan switch is a complex crossover switch
used in electrical or optical switch
es.
It is named for its resemblance to the roots of the banyan tree which cross over in complex patterns. Logical banyan switches are used in logic or signal pathways to crossover switching of signals onto new pathways.
They can be mechanical Microelectromechanical systems
, electrical or optical NLO
. Their complexity depends on the topology of the individual switches in a switch matrix (how wide it is by how many 'plies' or layers of switches it takes), to implement a desired crossover logic.
Other formulas are used for differing number of crossover layers, and scaling is possible, but becomes very large and complex with large N×N arrays. CAD and AI
can be used to take the drudgery out of creating these designs. A banyan network is implemented by interconnecting 2×2 switching networks in multiple and recursive stages.
The switches are measured by how many stages, and how many up/down sorters and crosspoints they have. Switches often have buffers built-in for faster switching.
A typical switch may have:
This results in 3 level sorting for a 3 stage banyan network switch.
Consider a 2×2 banyan switch, which requires (2/2) log2 2 = 1 switching element. This switch takes two inputs, numbered 0 and 1, and two outputs, numbered 0 and 1. Every packet that comes in has a header that contains one bit indicating what its destination is (either 0 or 1). If the switch reads the bit and it has value 0, it sends the packet to its higher output (which is 0 in this case), and to its lower output if the routing bit is one. By connecting these switching elements in series and parallel it is possible therefore, to route packets in more complicated ways depending on the desired routes to establish.
and VLA
s.
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
, a banyan switch is a complex crossover switch
Crossover switch
In electronics, a crossover switch or matrix switch is a switch connecting multiple inputs to multiple outputs using complex array matrices designed to switch any one input path to any one output path...
used in electrical or optical switch
Optical switch
In telecommunication, an optical switch is a switch that enables signals in optical fibers or integrated optical circuits to be selectively switched from one circuit to another....
es.
It is named for its resemblance to the roots of the banyan tree which cross over in complex patterns. Logical banyan switches are used in logic or signal pathways to crossover switching of signals onto new pathways.
They can be mechanical Microelectromechanical systems
Microelectromechanical systems
Microelectromechanical systems is the technology of very small mechanical devices driven by electricity; it merges at the nano-scale into nanoelectromechanical systems and nanotechnology...
, electrical or optical NLO
Nonlinear optics
Nonlinear optics is the branch of optics that describes the behavior of light in nonlinear media, that is, media in which the dielectric polarization P responds nonlinearly to the electric field E of the light...
. Their complexity depends on the topology of the individual switches in a switch matrix (how wide it is by how many 'plies' or layers of switches it takes), to implement a desired crossover logic.
Design
Typical crossover matrices follow this formula: an N×N banyan switch uses (N/2) log2 N elements.Other formulas are used for differing number of crossover layers, and scaling is possible, but becomes very large and complex with large N×N arrays. CAD and AI
Ai
AI, A.I., Ai, or ai may refer to:- Computers :* Artificial intelligence, a branch of computer science* Ad impression, in online advertising* .ai, the ISO Internet 2-letter country code for Anguilla...
can be used to take the drudgery out of creating these designs. A banyan network is implemented by interconnecting 2×2 switching networks in multiple and recursive stages.
The switches are measured by how many stages, and how many up/down sorters and crosspoints they have. Switches often have buffers built-in for faster switching.
A typical switch may have:
- A 2×2 and 4×4 down sorter
- Followed by an 8×8 up sorter
- Followed by a 2×2 crosspoint banyan switch network
This results in 3 level sorting for a 3 stage banyan network switch.
A simple example
Consider a 2×2 banyan switch, which requires (2/2) log2 2 = 1 switching element. This switch takes two inputs, numbered 0 and 1, and two outputs, numbered 0 and 1. Every packet that comes in has a header that contains one bit indicating what its destination is (either 0 or 1). If the switch reads the bit and it has value 0, it sends the packet to its higher output (which is 0 in this case), and to its lower output if the routing bit is one. By connecting these switching elements in series and parallel it is possible therefore, to route packets in more complicated ways depending on the desired routes to establish.
Future directions and further information
The future is moving to larger arrays of inputs and outputs needed in a very small space. See wafer fabricationWafer fabrication
Wafer fabrication is a procedure composed of many repeated sequential processes to produce complete electrical or photonic circuits. Examples include production of radio frequency amplifiers, LEDs, optical computer components, and CPUs for computers...
and VLA
VLA
VLA may refer to:Transport* RUM-139 VL-ASROC, a vertically-launched anti-submarine rocket* Very Light Aircraft, a category of aircraft, per the European EASA CS-VLA specificationsGovernment Agencies...
s.
See also
- Crossover switchCrossover switchIn electronics, a crossover switch or matrix switch is a switch connecting multiple inputs to multiple outputs using complex array matrices designed to switch any one input path to any one output path...
es - Crossbar switchCrossbar switchIn electronics, a crossbar switch is a switch connecting multiple inputs to multiple outputs in a matrix manner....
es - Clos networkClos networkIn the field of telecommunications, a Clos network is a kind of multistage circuit switching network, first formalized by Charles Clos in 1953, which represents a theoretical idealization of practical multi-stage telephone switching systems. Clos networks are required when the physical circuit...
a non blocking crossover switch that needs fewer than N² switches - Nonblocking minimal spanning switchNonblocking minimal spanning switchA nonblocking minimal spanning switch is a device that can connect N inputs to N outputs in any combination. The most familiar use of switches of this type is in a telephone exchange. The term "non-blocking" means that if it is not defective, it can always make the connection...
and signal switching. - Optical computer