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Wavefront Arbiter
A Wavefront arbiter is a circuit used to make decisions which control the crossbar of a high capacity switch fabric in parallel. It was commercialized in the TT1 and TTx chip sets designed by Abrizio and sold by PMC-Sierra. Context A crossbar is the central portion of a crossbar switch fabric which connects the inputs to the outputs. A set of decisions of which inputs are connected to which outputs must be made each arbitration period. In high speed cell switching or packet switching applications, the arbitration period is very short. There are often millions or billions of arbitration periods per second. An arbiter is the circuit that makes the decision as to which of the crossbar's many switches should be closed. Speed is a key design criterion of an arbiter in some applications. Algorithm description A wavefront arbiter is a particular type of arbiter that is optimized for high-speed operation. For a unicast switch, the algorithm is as follows: # The decision starts at a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abrizio
Abrizio was a fabless semiconductor company which made switching fabric chip sets (integrated circuits for computer network switches). Their chip set, the TT1, was used by several large system development companies as the core switch fabric in their high value communication systems. Founding Abrizio was founded in 1997, by Professor Nick McKeown as a spinout of the Tiny-tera project at Stanford University. It received US$6M of funding from Benchmark Capital and Sequoia Capital. Product and technology The product name TT1 referred to "Tiny Tera" meaning a small, highly integrated semiconductor implementation of a terabit/s capacity switching fabric. The Stanford program demonstrated a scalable packet switch that had a terabit-per-second performance in CMOS. Abrizio was the first to introduce a more optimized Input-Buffered Output Queued Switch Fabrics, which addressed the memory efficiency issue of similar technologies. Its technology made better use of memory, making the TT1 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PMC-Sierra
PMC-Sierra was a global fabless semiconductor company with offices worldwide that developed and sold semiconductor devices into the storage, communications, optical networking, printing, and embedded computing marketplaces. On January 15, 2016, Microsemi Corporation completed acquisition of PMC-Sierra through Microsemi's subsidiary Lois Acquisition. History Sierra Semiconductor was founded in 1984 in San Jose, California by James Diller. It received funding on January 11, 1984 from Sequoia Capital, and went public in 1991. Pacific Microelectronics Centre (PMC) in Burnaby, British Columbia, Canada, was spun off from Microtel Pacific Research (the research arm of BC TEL at the time) to develop Asynchronous Transfer Mode (ATM) and later SONET integrated circuits (chips). With investment from Sierra Semiconductor, PMC was established in 1992 as a private company focused on providing networking semiconductors, and became a wholly owned, independently operated subsidiary of Sierr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossbar Switch
In electronics and telecommunications, a crossbar switch (cross-point switch, matrix switch) is a collection of switches arranged in a matrix configuration. A crossbar switch has multiple input and output lines that form a crossed pattern of interconnecting lines between which a connection may be established by closing a switch located at each intersection, the elements of the matrix. Originally, a crossbar switch consisted literally of crossing metal bars that provided the input and output paths. Later implementations achieved the same switching topology in solid-state electronics. The crossbar switch is one of the principal telephone exchange architectures, together with a rotary switch, memory switch, and a crossover switch. General properties A crossbar switch is an assembly of individual switches between a set of inputs and a set of outputs. The switches are arranged in a matrix. If the crossbar switch has M inputs and N outputs, then a crossbar has a matrix with ''M'' × ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Packet Switching
In telecommunications, packet switching is a method of grouping Data (computing), data into ''network packet, packets'' that are transmitted over a digital Telecommunications network, network. Packets are made of a header (computing), header and a payload (computing), payload. Data in the header is used by networking hardware to direct the packet to its destination, where the payload is extracted and used by an operating system, application software, or protocol suite, higher layer protocols. Packet switching is the primary basis for data communications in computer networks worldwide. In the early 1960s, American computer scientist Paul Baran developed the concept that he called "distributed adaptive message block switching", with the goal of providing a fault-tolerant, efficient routing method for telecommunication messages as part of a research program at the RAND Corporation, funded by the United States Department of Defense. His ideas contradicted then-established principles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arbiter (electronics)
Arbiters are electronic devices that allocate access to shared resources. Bus arbiter A bus arbiter is a device used in a multi-master bus system to decide which bus master will be allowed to control the bus for each bus cycle. The most common kind of bus arbiter is the memory arbiter in a system bus system. A memory arbiter is a device used in a shared memory system to decide, for each memory cycle, which CPU will be allowed to access that shared memory. Some atomic instructions depend on the arbiter to prevent other CPUs from reading memory "halfway through" atomic read-modify-write instructions. A memory arbiter is typically integrated into the memory controller/DMA controller. Some systems, such as conventional PCI, have a single centralized bus arbitration device that one can point to as "the" bus arbiter. Other systems use decentralized bus arbitration, where all the devices cooperate to decide who goes next. When every CPU connected to the memory arbiter has synch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardware Register
In digital electronics, especially computing, hardware registers are circuits typically composed of flip flops, often with many characteristics similar to memory, such as: * The ability to read or write multiple bits at a time, and * Using an address to select a particular register in a manner similar to a memory address. Their distinguishing characteristic, however, is that they also have special hardware-related functions beyond those of ordinary memory. So, depending on the point of view, hardware registers are like memory with additional hardware-related functions; or, memory circuits are like hardware registers that just store data. Hardware registers are used in the interface between software and peripherals. Software writes them to send information to the device, and reads them to get information from the device. Some hardware devices also include registers that are not visible to software, for their internal use. Depending on their complexity, modern hardware devices c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computation
Computation is any type of arithmetic or non-arithmetic calculation that follows a well-defined model (e.g., an algorithm). Mechanical or electronic devices (or, historically, people) that perform computations are known as ''computers''. An especially well-known discipline of the study of computation is computer science. Physical process of Computation Computation can be seen as a purely physical process occurring inside a closed physical system called a computer. Examples of such physical systems are digital computers, mechanical computers, quantum computers, DNA computers, molecular computers, microfluidics-based computers, analog computers, and wetware computers. This point of view has been adopted by the physics of computation, a branch of theoretical physics, as well as the field of natural computing. An even more radical point of view, pancomputationalism (inaudible word), is the postulate of digital physics that argues that the evolution of the universe is itself ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiconductor
A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glass. Its electrical resistivity and conductivity, resistivity falls as its temperature rises; metals behave in the opposite way. Its conducting properties may be altered in useful ways by introducing impurities ("doping (semiconductor), doping") into the crystal structure. When two differently doped regions exist in the same crystal, a semiconductor junction is created. The behavior of charge carriers, which include electrons, ions, and electron holes, at these junctions is the basis of diodes, transistors, and most modern electronics. Some examples of semiconductors are silicon, germanium, gallium arsenide, and elements near the so-called "metalloid staircase" on the periodic table. After silicon, gallium arsenide is the second-most common s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Randomization
Randomization is the process of making something random. Randomization is not haphazard; instead, a random process is a sequence of random variables describing a process whose outcomes do not follow a deterministic pattern, but follow an evolution described by probability distributions. For example, a random sample of individuals from a population refers to a sample where every individual has a known probability of being sampled. This would be contrasted with nonprobability sampling where arbitrary individuals are selected. In various contexts, randomization may involve: * generating a random permutation of a sequence (such as when shuffling cards); * selecting a random sample of a population (important in statistical sampling); * allocating experimental units via random assignment to a treatment or control condition; * generating random numbers (random number generation); or * transforming a data stream (such as when using a scrambler in telecommunications). Applications Randomi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multicast
In computer networking, multicast is group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast should not be confused with physical layer point-to-multipoint communication. Group communication may either be application layer multicast or network-assisted multicast, where the latter makes it possible for the source to efficiently send to the group in a single transmission. Copies are automatically created in other network elements, such as routers, switches and cellular network base stations, but only to network segments that currently contain members of the group. Network assisted multicast may be implemented at the data link layer using one-to-many addressing and switching such as Ethernet multicast addressing, Asynchronous Transfer Mode (ATM), point-to-multipoint virtual circuits (P2MP) or InfiniBand multicast. Network-assisted multicast may also be impl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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