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Wormhole Routing
Wormhole flow control, also called wormhole switching or wormhole routing, is a system of simple flow control in computer networking based on known fixed links. It is a subset of flow control methods called ''flit-buffer flow control''. Switching is a more appropriate term than routing, as "routing" defines the route or path taken to reach the destination. The wormhole technique does not dictate the route to the destination but decides when the packet moves forward from a router. Wormhole switching is widely used in multicomputers because of its low latency and small requirements at the nodes. Wormhole routing supports very low-latency, high-speed, guaranteed delivery of packets suitable for real-time communication. Mechanism principle In the wormhole flow control, each packet is broken into small pieces called flits (flow control units or flow control digits). Commonly, the first flits, called the header flits, holds information about this packet's route (for example, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flow Control (data)
In data communications, flow control is the process of managing the rate of data transmission between two nodes to prevent a fast sender from overwhelming a slow receiver. Flow control should be distinguished from congestion control, which is used for controlling the flow of data when congestion has actually occurred. Flow control mechanisms can be classified by whether or not the receiving node sends feedback to the sending node. Flow control is important because it is possible for a sending computer to transmit information at a faster rate than the destination computer can receive and process it. This can happen if the receiving computers have a heavy traffic load in comparison to the sending computer, or if the receiving computer has less processing power than the sending computer. Stop-and-wait Stop-and-wait flow control is the simplest form of flow control. In this method the message is broken into multiple frames, and the receiver indicates its readiness to receive a fra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
8-bit
In computer architecture, 8-bit integers or other data units are those that are 8 bits wide (1 octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers or data buses of that size. Memory addresses (and thus address buses) for 8-bit CPUs are generally larger than 8-bit, usually 16-bit. 8-bit microcomputers are microcomputers that use 8-bit microprocessors. The term '8-bit' is also applied to the character sets that could be used on computers with 8-bit bytes, the best known being various forms of extended ASCII, including the ISO/IEC 8859 series of national character sets especially Latin 1 for English and Western European languages. The IBM System/360 introduced byte-addressable memory with 8-bit bytes, as opposed to bit-addressable or decimal digit-addressable or word-addressable memory, although its general-purpose registers were 32 bits wide, and addresses were contained in the lower 24 bits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flow Control (data)
In data communications, flow control is the process of managing the rate of data transmission between two nodes to prevent a fast sender from overwhelming a slow receiver. Flow control should be distinguished from congestion control, which is used for controlling the flow of data when congestion has actually occurred. Flow control mechanisms can be classified by whether or not the receiving node sends feedback to the sending node. Flow control is important because it is possible for a sending computer to transmit information at a faster rate than the destination computer can receive and process it. This can happen if the receiving computers have a heavy traffic load in comparison to the sending computer, or if the receiving computer has less processing power than the sending computer. Stop-and-wait Stop-and-wait flow control is the simplest form of flow control. In this method the message is broken into multiple frames, and the receiver indicates its readiness to receive a fra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Source Routing
In computer networking, source routing, also called path addressing, allows a sender of a data packet to partially or completely specify the route the packet takes through the network. In contrast, in conventional routing, routers in the network determine the path incrementally based on the packet's destination. Another routing alternative, label switching, is used in connection-oriented networks such as X.25, Frame Relay, Asynchronous Transfer Mode and Multiprotocol Label Switching. Source routing allows easier troubleshooting, improved traceroute, and enables a node to discover all the possible routes to a host. It does not allow a source to directly manage network performance by forcing packets to travel over one path to prevent congestion on another. Many high-performance interconnects including Myrinet, Quadrics, IEEE 1355, and SpaceWire support source routing. Internet Protocol In the Internet Protocol, two header options are available which are rarely used: " strict so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myrinet
Myrinet, ANSI/VITA 26-1998, is a high-speed local area networking system designed by the company Myricom to be used as an interconnect between multiple machines to form computer clusters. Description Myrinet was promoted as having lower protocol overhead than standards such as Ethernet, and therefore better throughput, less interference, and lower latency while using the host CPU. Although it can be used as a traditional networking system, Myrinet is often used directly by programs that "know" about it, thereby bypassing a call into the operating system. Earlier versions of Myrinet used a variety of media and connectors: * Generation 2 used copper media with DC-37 (Myrinet-LAN, M2L-* controllers and switches) or microribbon (Myrinet-SAN, M2M-*) connectors. * Generation 3 used copper media with HSSDC (Myrinet-Serial, M3S-*) or microribbon (Myrinet-SAN, M3M-*) connectors, or fiber with LC-connectors (Myrinet-Fiber, M3F-*). The later versions of Myrinet physically consist of two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Head-of-line Blocking
Head-of-line blocking (HOL blocking) in computer networking is a performance-limiting phenomenon that occurs when a queue of packets is held up by the first packet in the queue. This occurs, for example, in input-buffered network switches, out-of-order delivery and multiple requests in HTTP pipelining. Network switches A switch may be composed of buffered input ports, a switch fabric, and buffered output ports. If first-in first-out (FIFO) input buffers are used, only the oldest packet is available for forwarding. If the oldest packet cannot be transmitted due to its target output being busy, then more recent arrivals cannot be forwarded. The output may be busy if there is output contention. Without HOL blocking, the new arrivals could potentially be forwarded around the stuck oldest packet to their respective destinations. HOL blocking can produce performance-degrading effects in input-buffered systems. This phenomenon limits the throughput of switches. For FIFO input bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Output Queueing
Virtual output queueing (VOQ) is a technique used in certain network switch architectures where, rather than keeping all traffic in a single queue, separate queues are maintained for each possible output location. It addresses a common problem known as head-of-line blocking. Description In VOQ, the physical buffer of each input port maintains a separate virtual queue for each output port. Therefore congestion on an egress port will block only the virtual queue for this particular egress port. Other packets in the same physical buffer destined to different (non-congested) output ports are in separate virtual queues and can therefore still be processed. In a traditional setup, the blocked packet for the congested egress port would have blocked the whole physical buffer, resulting in head-of-line blocking. It has been shown that VOQ can achieve 100% throughput performance with an effective scheduling algorithm. This scheduling algorithm should be able to provide a high speed mapping ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SpaceWire
SpaceWire is a spacecraft communication network based in part on the IEEE 1355 standard of communications. It is coordinated by the European Space Agency (ESA) in collaboration with international space agencies including NASA, JAXA, and RKA. Within a SpaceWire network the nodes are connected through low-cost, low- latency, full-duplex, point-to-point serial links, and packet switching wormhole routing routers. Architecture Physical layer SpaceWire's modulation and data formats generally follow the data strobe encoding - differential ended signaling (DS-DE) part of the IEEE Std 1355-1995. SpaceWire utilizes asynchronous communication and allows speeds between 2 Mbit/s and 200 Mbit/s, with initial signalling rate of 10 Mbit/s. DS-DE is well-favored because it describes modulation, bit formats, routing, flow control, and error detection in hardware, with little need for software. SpaceWire also has very low error rates, deterministic system behavior, and rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEEE 1355
IEEE Standard 1355-1995, IEC 14575, or ISO 14575 is a data communications standard for Heterogeneous Interconnect (HIC). IEC 14575 is a low-cost, low latency, scalable serial interconnection system, originally intended for communication between large numbers of inexpensive computers. IEC 14575 lacks many of the complexities of other data networks. The standard defined several different types of transmission media (including wires and optic fiber), to address different applications. Since the high-level network logic is compatible, inexpensive electronic adapters are possible. IEEE 1355 is often used in scientific laboratories. Promoters include large laboratories, such as CERN, and scientific agencies. For example, the ESA advocates a derivative standard called SpaceWire. Goals The protocol was designed for a simple, low cost switched network made of point-to-point links. This network sends variable length data packets reliably at high speed. It routes the packets using wormh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integrated Circuit
An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components are etched onto a small, flat piece ("chip") of semiconductor material, usually silicon. Integrated circuits are used in a wide range of electronic devices, including computers, smartphones, and televisions, to perform various functions such as processing and storing information. They have greatly impacted the field of electronics by enabling device miniaturization and enhanced functionality. Integrated circuits are orders of magnitude smaller, faster, and less expensive than those constructed of discrete components, allowing a large transistor count. The IC's mass production capability, reliability, and building-block approach to integrated circuit design have ensured the rapid adoption of standardized ICs in place of designs using discre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network On A Chip
A network on a chip or network-on-chip (NoC or )This article uses the convention that "NoC" is pronounced . Therefore, it uses the convention "a" for the indefinite article corresponding to NoC ("a NoC"). Other sources may pronounce it as and therefore use "an NoC". is a network-based communications subsystem on an integrated circuit ("microchip"), most typically between modules in a system on a chip ( SoC). The modules on the IC are typically semiconductor IP cores schematizing various functions of the computer system, and are designed to be modular in the sense of network science. The network on chip is a router-based packet switching network between SoC modules. NoC technology applies the theory and methods of computer networking to on-chip communication and brings notable improvements over conventional bus and crossbar communication architectures. Networks-on-chip come in many network topologies, many of which are still experimental as of 2018. In 2000s, res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
