In Telecommunication and Computer networking, time-driven switching (TDS) is a node by node time variant implementation of Circuit switching, where the propagating datagram is shorter in space than the distance between source and destination. With TDS it is no longer necessary to own a complete circuit between source and destination, but only the fraction of circuit where the propagating datagram is temporarily located. TDS adds flexibility and capacity to Circuit Switched networks but requires precise synchronization among nodes and propagating datagrams.
Telecommunication is the transmission of signs, signals, messages, words, writings, images and sounds or information of any nature by wire, radio, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology. It is transmitted either electrically over physical media, such as cables, or via electromagnetic radiation. Such transmission paths are often divided into communication channels which afford the advantages of multiplexing. Since the Latin term communicatio is considered the social process of information exchange, the term telecommunications is often used in its plural form because it involves many different technologies.
Circuit switching is a method of implementing a telecommunications network in which two network nodes establish a dedicated communications channel (circuit) through the network before the nodes may communicate. The circuit guarantees the full bandwidth of the channel and remains connected for the duration of the communication session. The circuit functions as if the nodes were physically connected as with an electrical circuit.
Datagrams are formatted according to schedules that depend on Quality of service and availability of switching nodes and physical links. Respect to Circuit switching the added time dimension introduces additional complexity to network management. Like Circuit switching, TDS operates without buffers and header processing according to the pipeline forwarding principle; therefore an all optical implementation with Optical fibers and Optical Switches is possible with low cost. The TDS concept itself pervades and is applicable with advantage to existing data switching technologies, including Packet switching, where packets, or sets of packets become the datagrams that are routed through the network.
Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network or a cloud computing service, particularly the performance seen by the users of the network. To quantitatively measure quality of service, several related aspects of the network service are often considered, such as packet loss, bit rate, throughput, transmission delay, availability, jitter, etc.
Pipeline forwarding (PF) applies to packet forwarding in computer networks the basic concept of pipelining, which has been widely and successfully used in computing — specifically, in the architecture of all major central processing units (CPUs) — and manufacturing — specifically in assembly lines of various industries starting from automotive to many others. Pipelining is known to be optimal independent of the specific instantiation. In particular, PF is optimal from various points of view:
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.
TDS has been invented in 2002 by Prof. Mario Baldi and prof. Yoram Ofek of Synchrodyne Networks, Inc. that is the assignee of several patents issued by both the United States Patent and Trademark Office and the European Patent Office.
Yoram Ofek was a Marie Curie Chair and full professor in the Information Engineering and Computer Science Department at the University of Trento, Italy. He was the inventor of 45 US and European patents and published more than 120 journal and conference papers. He invented several novel architectures for networking, computing and storage. He was elected IEEE Fellow in 2006 for his contributions to switching, scheduling and synchronization in data networks.
The United States Patent and Trademark Office (USPTO) is an agency in the U.S. Department of Commerce that issues patents to inventors and businesses for their inventions, and trademark registration for product and intellectual property identification.
The European Patent Office (EPO) is one of the two organs of the European Patent Organisation (EPOrg), the other being the Administrative Council. The EPO acts as executive body for the Organisation while the Administrative Council acts as its supervisory body as well as, to a limited extent, its legislative body. The actual legislative power to revise the European Patent Convention lies with the Contracting States themselves when meeting at a Conference of the Contracting States.
The Internet Protocol (IP) is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.
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.
In computer networking, the User Datagram Protocol (UDP) is one of the core members of the Internet protocol suite. The protocol was designed by David P. Reed in 1980 and formally defined in RFC 768. With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol (IP) network. Prior communications are not required in order to set up communication channels or data paths.
A datagram is a basic transfer unit associated with a packet-switched network. Datagrams are typically structured in header and payload sections. Datagrams provide a connectionless communication service across a packet-switched network. The delivery, arrival time, and order of arrival of datagrams need not be guaranteed by the network.
Network topology is the arrangement of the elements of a communication network. Network topology can be used to define or describe the arrangement of various types of telecommunication networks, including command and control radio networks, industrial fieldbusses, and computer networks.
In telecommunications, a protocol data unit (PDU) is a single unit of information transmitted among peer entities of a computer network. A PDU is composed of protocol specific control information and user data. In the layered architectures of communication protocol stacks, each layer implements protocols tailored to the specific type or mode of data exchange.
A virtual circuit (VC) is a means of transporting data over a packet switched computer network in such a way that it appears as though there is a dedicated physical layer link between the source and destination end systems of this data. The term virtual circuit is synonymous with virtual connection and virtual channel. Before a connection or virtual circuit may be used, it has to be established, between two or more nodes or software applications, by configuring the relevant parts of the interconnecting network. After that, a bit stream or byte stream may be delivered between the nodes; hence, a virtual circuit protocol allows higher level protocols to avoid dealing with the division of data into segments, packets, or frames.
In computer networking, the transport layer is a conceptual division of methods in the layered architecture of protocols in the network stack in the Internet protocol suite and the OSI model. The protocols of this layer provide host-to-host communication services for applications. It provides services such as connection-oriented communication, reliability, flow control, and multiplexing.
The CYCLADES computer network was a French research network created in the early 1970s. It was one of the pioneering networks experimenting with the concept of packet switching, and was developed to explore alternatives to the ARPANET design. The network supported general local network research.
Connection-oriented communication is a network communication mode in telecommunications and computer networking, where a communication session or a semi-permanent connection is established before any useful data can be transferred, and where a stream of data is delivered in the same order as it was sent. The alternative to connection-oriented transmission is connectionless communication, for example the datagram mode communication used by the IP and UDP protocols, where data may be delivered out of order, since different network packets are routed independently, and may be delivered over different paths.
Optical IP Switching (OIS), is a novel method of creating transparent optical connections between network nodes using a flow-based approach. An IP flow is a collection of IP packets going from the same source to the same destination: the exchange of IP packets is the mechanism that allows the transport of information over the Internet.
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.
When realizing pipeline forwarding a predefined schedule for forwarding a pre-allocated amount of bytes during one or more time frames along a path of subsequent switches establishes a synchronous virtual pipe (SVP). The SVP capacity is determined by the total number of bits allocated in every time cycle for the SVP. For example, for a 10 ms time cycle, if 20,000 bits are allocated during each of 2 time frames, the SVP capacity is 4 Mbit/s.
Time-driven priority (TDP) is a synchronous packet scheduling technique that implements UTC-based pipeline forwarding and can be combined with conventional IP routing to achieve the higher flexibility than another pipeline forwarding implementation known as time-driven switching (TDS) or fractional lambda switching (FλS). Packets entering a switch from the same input port during the same [time frame] (TF) can be sent out from different output ports, according to the rules that drive IP packet routing. Operation in accordance to pipeline forwarding principles ensures deterministic quality of service and low complexity packet scheduling. Specifically, packets scheduled for transmission during a TF are given maximum priority; if resources have been properly reserved, all scheduled packets will be at the output port and transmitted before their TF ends.
Fractional lambda switching (FλS) leverages on time-driven switching (TDS) to realize sub-lambda switching in highly scalable dynamic optical networking, which requires minimum buffers. Fractional lambda switching implies switching fractions of optical channels as opposed to whole lambda switching where whole optical channels are the switching unit. In this context, TDS has the same general objectives as optical burst switching and optical packet switching: realizing all-optical networks with high wavelength utilization. TDS operation is based on time frames (TFs) that can be viewed as virtual containers for multiple IP packets that are switched at every TDS switch based on and coordinated by the UTC signal implementing pipeline forwarding. In the context of optical networks, synchronous virtual pipes SVPs typical of pipeline forwarding are called fractional lambda pipes (FλPs).
Associativity-based routing is a mobile routing protocol invented for wireless ad hoc networks, also known as mobile ad hoc networks (MANETs) and wireless mesh networks. ABR was invented in 1993, filed for a U.S. patent in 1996, and granted the patent in 1999. ABR was invented by Chai Keong Toh while doing his Ph.D. at Cambridge University.
Data transmission is the transfer of data over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibers, wireless communication channels, storage media and computer buses. The data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal.
Network architecture is the design of a computer network. It is a framework for the specification of a network's physical components and their functional organization and configuration, its operational principles and procedures, as well as communication protocols used.