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Packet Forwarding
Packet forwarding is the relaying of packets from one network segment to another by nodes in a computer network. The network layer in the OSI model is responsible for packet forwarding. Models The simplest forwarding modelunicastinginvolves a packet being relayed from link to link along a chain leading from the packet's source to its destination. However, other forwarding strategies are commonly used. Broadcasting requires a packet to be duplicated and copies sent on multiple links with the goal of delivering a copy to every device on the network. In practice, broadcast packets are not forwarded everywhere on a network, but only to devices within a broadcast domain, making ''broadcast'' a relative term. Less common than broadcasting, but perhaps of greater utility and theoretical significance, is multicasting, where a packet is selectively duplicated and copies delivered to each of a set of recipients. Networking technologies tend to naturally support certain forwarding mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Packet (information Technology)
In telecommunications and computer networking, a network packet is a formatted unit of data carried by a packet-switched network. A packet consists of control information and user data; the latter is also known as the ''payload''. Control information provides data for delivering the payload (e.g., source and destination network addresses, error detection codes, or sequencing information). Typically, control information is found in packet headers and trailers. In packet switching, the bandwidth of the transmission medium is shared between multiple communication sessions, in contrast to circuit switching, in which circuits are preallocated for the duration of one session and data is typically transmitted as a continuous bit stream. Terminology In the seven-layer OSI model of computer networking, ''packet'' strictly refers to a protocol data unit at layer 3, the network layer. A data unit at layer 2, the data link layer, is a '' frame''. In layer 4, the transport layer, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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10BASE-T
1 (one, unit, unity) is a number representing a single or the only entity. 1 is also a numerical digit and represents a single unit of counting or measurement. For example, a line segment of ''unit length'' is a line segment of length 1. In conventions of sign where zero is considered neither positive nor negative, 1 is the first and smallest positive integer. It is also sometimes considered the first of the infinite sequence of natural numbers, followed by 2, although by other definitions 1 is the second natural number, following 0. The fundamental mathematical property of 1 is to be a multiplicative identity, meaning that any number multiplied by 1 equals the same number. Most if not all properties of 1 can be deduced from this. In advanced mathematics, a multiplicative identity is often denoted 1, even if it is not a number. 1 is by convention not considered a prime number; this was not universally accepted until the mid-20th century. Additionally, 1 is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Per-hop Behaviour
In computer networking, per-hop behaviour (PHB) is a term used in differentiated services (DiffServ) or multiprotocol label switching Multiprotocol Label Switching (MPLS) is a routing technique in telecommunications networks that directs data from one node to the next based on labels rather than network addresses. Whereas network addresses identify endpoints the labels identi ... (MPLS). It defines the policy and priority applied to a packet when traversing a hop (such as a router) in a DiffServ network. See also * Best-effort delivery {{compu-network-stub Internet architecture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Node-to-node Data Transfer
In telecommunications, node-to-node data transfer is the movement of data from one node of a network to the next. In the OSI model it is handled by the lowest two layers, the data link layer and the physical layer. In most communication systems, the transmitting point applies source coding, followed by channel coding, and lastly, line coding. This produces the baseband signal. The presence of filters may perform pulse shaping. Some systems then use modulation to multiplex many baseband signals into a broadband signal. The receiver un-does these transformations in reverse order: demodulation, trellis decoding, error detection and correction, decompression. Some communication systems omit one or more of these steps, or use techniques that combine several of these steps together. For example, a Morse code transmitter combines source coding, channel coding, and line coding into one step, typically followed by an amplitude modulation step. Barcodes, on the other hand, add a checksum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Forwarding Information Base
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 controller 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. Applications at data link layer At the data link layer, a FIB is most notably used to facilitate Ethernet bridging based on MAC addresses. Other data-link-layer technologies using FIBs include Frame Relay, Asynchronous Transfer Mode (ATM) and multiprotocol label switching (MPLS). Bridging The role of an Ethernet switch is to forward Ethernet frames from one port to another. The presence of a FIB is one attribute that separates a switch from a hub. With ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Equal-cost Multi-path Routing
Equal-cost multi-path routing (ECMP) is a routing strategy where packet forwarding to a single destination can occur over multiple best paths with equal routing priority. Multi-path routing can be used in conjunction with most routing protocols because it is a per-hop local decision made independently at each router. It can substantially increase bandwidth by load-balancing traffic over multiple paths; however, there may be significant problems in deploying it in practice. History Load balancing by per-packet multipath routing was generally disfavored due to the impact of rapidly changing latency, packet reordering and maximum transmission unit (MTU) differences within a network flow, which could disrupt the operation of many Internet protocols, most notably TCP and path MTU discovery. RFC 2992 analyzed one particular multipath routing strategy involving the assignment of flows through hashing flow-related data in the packet header. This solution is designed to avoid these prob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Cut-through Switching
Rat running (also known as rodent running, cut-through driving, or dive-bombing) is the practice by motorists of using residential side streets or any unintended short cut such as a parking lot, delivery service lane or cemetery road instead of the intended main road in urban or suburban areas. Background Rat running is a tactic used to avoid heavy traffic and long delays at traffic signals or other obstacles, even where there are traffic calming measures to discourage its use or laws against taking certain routes. Rat runs are frequently taken by motorists familiar with the local geography. Rat running is controversial. When traffic is especially heavy on a highway or main road, rat-running vehicles may cause another traffic jam on the rat-run streets, along with accompanying problems such as collisions, pollution from exhaust, and road rage. It is sometimes opposed by residents on the affected streets, as they may regard it as a disturbance of their peace. Sometimes, it cau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Store-and-forward
Store and forward is a telecommunications technique in which information is sent to an intermediate station where it is kept and sent at a later time to the final destination or to another intermediate station. The intermediate station, or node in a networking context, verifies the integrity of the message before forwarding it. In general, this technique is used in networks with intermittent connectivity, especially in the wilderness or environments requiring high mobility. It may also be preferable in situations when there are long delays in transmission and variable and high error rates, or if a direct, end-to-end connection is not available. Modern store and forward networking * Store and forward originates with delay-tolerant networks. No real-time services are available for these kinds of networks. * Logistical Networking is a scalable form of store and forward networking that exposes network-embedded buffers on intermediate nodes and allows flexible creation of services b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Internet
The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a ''internetworking, network of networks'' that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and Web application, applications of the World Wide Web (WWW), email, electronic mail, internet telephony, telephony, and file sharing. The origins of the Internet date back to the development of packet switching and research commissioned by the United States Department of Defense in the 1960s to enable time-sharing of computers. The primary precursor network, the ARPANET, initially served as a backbone for interconnection of regional academic and mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Bridging (networking)
A network bridge is a computer networking device that creates a single, aggregate network from multiple communication networks or network segments. This function is called network bridging. Bridging is distinct from routing. Routing allows multiple networks to communicate independently and yet remain separate, whereas bridging connects two separate networks as if they were a single network. In the OSI model, bridging is performed in the data link layer (layer 2). If one or more segments of the bridged network are wireless, the device is known as a wireless bridge. The main types of network bridging technologies are simple bridging, multiport bridging, and learning or transparent bridging. Transparent bridging Transparent bridging uses a table called the forwarding information base to control the forwarding of frames between network segments. The table starts empty and entries are added as the bridge receives frames. If a destination address entry is not found in the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Routing
Routing is the process of selecting a path for traffic in a network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched telephone network (PSTN), and computer networks, such as the Internet. In packet switching networks, routing is the higher-level decision making that directs network packets from their source toward their destination through intermediate network nodes by specific packet forwarding mechanisms. Packet forwarding is the transit of network packets from one network interface to another. Intermediate nodes are typically network hardware devices such as routers, gateways, firewalls, or switches. General-purpose computers also forward packets and perform routing, although they have no specially optimized hardware for the task. The routing process usually directs forwarding on the basis of routing tables. Routing tables maintain a record of the routes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Network Switch
A network switch (also called switching hub, bridging hub, and, by the IEEE, MAC bridge) is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device. A network switch is a multiport network bridge that uses MAC addresses to forward data at the data link layer (layer 2) of the OSI model. Some switches can also forward data at the network layer (layer 3) by additionally incorporating routing functionality. Such switches are commonly known as layer-3 switches or multilayer switches. Switches for Ethernet are the most common form of network switch. The first MAC Bridge was invented in 1983 by Mark Kempf, an engineer in the Networking Advanced Development group of Digital Equipment Corporation. The first 2 port Bridge product (LANBridge 100) was introduced by that company shortly after. The company subsequently produced multi-port switches for both Ethernet and FDDI such as GigaSwitch. Digita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |