Turing switch

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Turing switch

In theoretical network science, the Turing switch is a logical construction modeling the operation of the network switch, just as in theoretical computer science a Turing machine models the operation of a computer. Both are named in honor of the English logician Alan Turing, although the research in Turing switches is not based on Turing's research. Some introductory research on the Turing switch was started at the University of Cambridge by Jon Crowcroft (Homepage).

Network science academic field

Network science is an academic field which studies complex networks such as telecommunication networks, computer networks, biological networks, cognitive and semantic networks, and social networks, considering distinct elements or actors represented by nodes and the connections between the elements or actors as links. The field draws on theories and methods including graph theory from mathematics, statistical mechanics from physics, data mining and information visualization from computer science, inferential modeling from statistics, and social structure from sociology. The United States National Research Council defines network science as "the study of network representations of physical, biological, and social phenomena leading to predictive models of these phenomena."

A network switch is a computer networking device that connects devices on a computer network by using packet switching to receive, process, and forward data to the destination device.

Theoretical computer science subfield of computer science and of mathematics

Theoretical computer science (TCS) is a subset of general computer science and mathematics that focuses on more mathematical topics of computing and includes the theory of computation.

In essence, Crowcroft suggests that instead of using general-purpose computers to do packet switching, the required operations should be reduced to application specific logic and then that application specific logic should be implemented using optical components. The work is not actually based on Turing's research.

Packet switching a method of grouping data which is transmitted over a digital network into packets

Packet switching is a method of grouping data that is transmitted over a digital network into packets. Packets are made of a header and a payload. Data in the header are used by networking hardware to direct the packet to its destination where the payload is extracted and used by application software. Packet switching is the primary basis for data communications in computer networks worldwide.

Optical networking is a means of communication that uses signals encoded onto light to transmit information among various nodes of a telecommunications network. They operate from the limited range of a local-area network (LAN) or over a wide-area network (WAN), which can cross metropolitan and regional areas all the way to national, international and transoceanic distances. It is a form of optical communication that relies on optical amplifiers, lasers or LEDs and wave division multiplexing (WDM) to transmit large quantities of data, generally across fiber-optic cables. Because it is capable of achieving extremely high bandwidth, it is an enabling technology for today’s Internet and the communication networks that transmit the vast majority of all human and machine-to-machine information.

A Turing switch consists of a switched fabric, one or more ingress interfaces (also referred to as sources), one or more egress interfaces (sinks), and a decision procedure to determine an egress interface given an ingress interface. Interfaces are sometimes referred to as ports. A packet (cell or switched unit) arrives at an ingress interface, the appropriate egress interface is determined by the decision procedure, and the packet is then transported across the switching fabric to the egress interface. A packet is a symbol or sequence of 1's and 0's. An ingress interface is connected to an ingress line and an egress interface to an egress line. The ingress line is said to feed the ingress interface; the egress interface feeds the egress line. [1]

Switched Fabric or switching fabric is a network topology in which network nodes interconnect via one or more network switches. Because a switched fabric network spreads network traffic across multiple physical links, it yields higher total throughput than broadcast networks, such as the early 10BASE5 version of Ethernet, or most wireless networks such as Wi-Fi.

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Related Research Articles

Multiprotocol Label Switching (MPLS) is a routing technique in telecommunications networks that directs data from one node to the next based on short path labels rather than long network addresses, thus avoiding complex lookups in a routing table and speeding traffic flows. The labels identify virtual links (paths) between distant nodes rather than endpoints. MPLS can encapsulate packets of various network protocols, hence the "multiprotocol" reference on its name. MPLS supports a range of access technologies, including T1/E1, ATM, Frame Relay, and DSL.

Turing machine Rule based abstract computation model

A Turing machine is a mathematical model of computation that defines an abstract machine, which manipulates symbols on a strip of tape according to a table of rules. Despite the model's simplicity, given any computer algorithm, a Turing machine capable of simulating that algorithm's logic can be constructed.

Synchronous optical networking

Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diodes (LEDs). At low transmission rates data can also be transferred via an electrical interface. The method was developed to replace the plesiochronous digital hierarchy (PDH) system for transporting large amounts of telephone calls and data traffic over the same fiber without the problems of synchronization.

The end-to-end principle is a design framework in computer networking. In networks designed according to this principle, application-specific features reside in the communicating end nodes of the network, rather than in intermediary nodes, such as gateways and routers, that exist to establish the network.

Donald Davies Welsh computer scientist

Donald Watts Davies, was a Welsh computer scientist who was employed at the UK National Physical Laboratory (NPL). In 1965 he developed the concept of packet switching, which is today the dominant basis for data communications in computer networks worldwide, and implemented it in the NPL network. This was independent of the work of Paul Baran in the United States who had a similar idea in the early 1960s. The ARPANET project, a precursor to the Internet, credited Davies for his influence.

Logic in computer science academic discipline

Logic in computer science covers the overlap between the field of logic and that of computer science. The topic can essentially be divided into three main areas:

In computer networking, ingress filtering is a technique used to ensure that incoming packets are actually from the networks from which they claim to originate. This can be used as a countermeasure against various spoofing attacks where the attacker's packets contain fake IP addresses to make it difficult to find the source of the attack. This technique is often used in the denial-of-service attack, and this is a primary target of ingress filtering.

Computer network collection of autonomous computers interconnected by a single technology

A computer network is a digital telecommunications network which allows nodes to share resources. In computer networks, computing devices exchange data with each other using connections between nodes. These data links are established over cable media such as wires or optic cables, or wireless media such as Wi-Fi.

In the field of telecommunications, a Clos network is a kind of multistage circuit-switching network which represents a theoretical idealization of practical, multistage switching systems. It was invented by Edson Erwin in 1938 and first formalized by Charles Clos in 1952.

Multiservice Switch (MSS) is originally a Nortel line of routers, historically called Passport, designed for carrier core and edge routing. They run the Passport Carrier Release operating system. The MSS has a significant installed base, with over 40,000 switches sold.

Catalyst 6500

The Catalyst 6500 is a modular chassis network switch manufactured by Cisco Systems since 1999, capable of delivering speeds of up to "400 million packets per second".

A forwarding information base (FIB), also known as a forwarding table or MAC table, is most commonly used in network bridging, routing, and similar functions to find the proper output network interface to which the input interface should forward a packet. It is a dynamic table that maps MAC addresses to ports. It is the essential mechanism that separates network switches from Ethernet hubs. Content-addressable memory (CAM) is typically used to efficiently implement the FIB, thus it is sometimes called a CAM table.

Forwarding plane

In routing, the forwarding plane, sometimes called the data plane or user plane, defines the part of the router architecture that decides what to do with packets arriving on an inbound interface. Most commonly, it refers to a table in which the router looks up the destination address of the incoming packet and retrieves the information necessary to determine the path from the receiving element, through the internal forwarding fabric of the router, and to the proper outgoing interface(s). The IP Multimedia Subsystem architecture uses the term transport plane to describe a function roughly equivalent to the routing control plane.

Jon Crowcroft British computer scientist

Jonathan Andrew "Jon" Crowcroft, FRS, FREng is the Marconi Professor of Communications Systems in the Computer Laboratory of the University of Cambridge and the Chair of the Programme Committee at the Alan Turing Institute.

PAROLI

PAROLI is a proprietary protocol used inside a multi-shelf Carrier Routing System from Cisco and stands for "parallel optical link."

In digital communications networks, packet processing refers to the wide variety of algorithms that are applied to a packet of data or information as it moves through the various network elements of a communications network.

The NPL Network or NPL Data Communications Network was a local area computer network operated by a team from the National Physical Laboratory in England that pioneered the concept of packet switching. Following a pilot experiment during 1967, elements of the first version of the network, Mark I, became operational during 1969 then fully operational in 1970, and the Mark II version operated from 1973 until 1986. The NPL network, followed by the wide area ARPANET in the United States, were the first two computer networks that implemented packet switching, and were interconnected in the early 1970s. The NPL network was designed and directed by Donald Davies.

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References

  1. ↑ Jon Crowcroft Turing Switches. Turing machines for all-optical Internet routing UCAM-CL-TR-556 ISSN   1476-2986 January 2003
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