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Heuristic Routing
Heuristic routing is a system used to describe how deliveries are made when problems in a network topology arise. Heuristic is an adjective used in relation to methods of learning, discovery, or problem solving. Routing is the process of selecting paths to specific destinations. Heuristic routing is used for traffic in the telecommunications networks and transport networks of the world. Heuristic routing is achieved using specific algorithms to determine a better, although not always optimal, path to a destination. When an interruption in a network topology occurs, the software running on the networking electronics can calculate another route to the desired destination via an alternate available path. According to : The heuristic approach to problem solving consists of applying human intelligence, experience, common sense and certain rules of thumb (or heuristics) to develop an acceptable, but not necessarily an optimum, solution to a problem. Of course, determining what constitute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Network Topology
Network topology is the arrangement of the elements (Data link, links, Node (networking), nodes, etc.) 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 Fieldbus, fieldbusses and computer networks. Network topology is the topological structure of a network and may be depicted physically or logically. It is an application of graph theory wherein communicating devices are modeled as nodes and the connections between the devices are modeled as links or lines between the nodes. Physical topology is the placement of the various components of a network (e.g., device location and cable installation), while logical topology illustrates how data flows within a network. Distances between nodes, physical interconnections, transmission rates, or signal types may differ between two different networks, yet their logical topologies may be identica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Maximum Transmission Unit
In computer networking, the maximum transmission unit (MTU) is the size of the largest protocol data unit (PDU) that can be communicated in a single network layer transaction. The MTU relates to, but is not identical to the maximum frame size that can be transported on the data link layer, e.g., Ethernet frame. Larger MTU is associated with reduced overhead. Smaller MTU values can reduce network delay. In many cases, MTU is dependent on underlying network capabilities and must be adjusted manually or automatically so as to not exceed these capabilities. MTU parameters may appear in association with a communications interface or standard. Some systems may decide MTU at connect time, e.g. using Path MTU Discovery. Applicability MTUs apply to communications protocols and network layers. The MTU is specified in terms of bytes or octets of the largest PDU that the layer can pass onwards. MTU parameters usually appear in association with a communications interface ( NIC, serial port, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Transportation Science
''Transportation Science'' is a bimonthly peer-reviewed academic journal published by the Institute for Operations Research and the Management Sciences (INFORMS). The studies published in the journal apply operations research techniques to problems in the full range of transportation sectors, including air travel, rail transport Rail transport (also known as train transport) is a means of transport using wheeled vehicles running in railway track, tracks, which usually consist of two parallel steel railway track, rails. Rail transport is one of the two primary means of ..., commuter lines, and vehicular travel/traffic. References External links * Operations research Management science Business and management journals English-language journals Academic journals established in 1967 Quarterly journals Transportation journals INFORMS academic journals {{management-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Turn Restriction Routing
A routing algorithm decides the path followed by a packet from the source to destination routers in a network. An important aspect to be considered while designing a routing algorithm is avoiding a deadlock. Turn restriction routing is a routing algorithm for mesh-family of topologies which avoids deadlocks by restricting the types of turns that are allowed in the algorithm while determining the route from source node to destination node in a network. Reason for deadlock A deadlock (shown in fig 1) is a situation in which no further transportation of packets can take place due to the saturation of network resources like buffers or links. The main reason for a deadlock is the cyclic acquisition of channels in the network. For example, consider there are four channels in a network. Four packets have filled up the input buffers of these four channels and needs to be forwarded to the next channel. Now assume that the output buffers of all these channels are also filled with packe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Bellman–Ford Algorithm
The Bellman–Ford algorithm is an algorithm that computes shortest paths from a single source vertex (graph theory), vertex to all of the other vertices in a weighted digraph. It is slower than Dijkstra's algorithm for the same problem, but more versatile, as it is capable of handling graphs in which some of the edge weights are negative numbers.Lecture 14 stanford.edu The algorithm was first proposed by , but is instead named after Richard Bellman and L. R. Ford Jr., Lester Ford Jr., who published it in #, 1958 and #, 1956, respectively. Edward F. Moore also published a variation of the algorithm in #, 1959, and for this reason it is also sometimes called the Bellman–Ford–Moore algorithm. Negative edge weights are found in various applications of graph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Ford–Fulkerson Algorithm
The Ford–Fulkerson method or Ford–Fulkerson algorithm (FFA) is a greedy algorithm that computes the maximum flow in a flow network. It is sometimes called a "method" instead of an "algorithm" as the approach to finding augmenting paths in a residual graph is not fully specified or it is specified in several implementations with different running times. It was published in 1956 by L. R. Ford Jr. and D. R. Fulkerson. The name "Ford–Fulkerson" is often also used for the Edmonds–Karp algorithm, which is a fully defined implementation of the Ford–Fulkerson method. The idea behind the algorithm is as follows: as long as there is a path from the source (start node) to the sink (end node), with available capacity on all edges in the path, we send flow along one of the paths. Then we find another path, and so on. A path with available capacity is called an augmenting path. Algorithm Let G(V,E) be a graph, and for each edge from to , let c(u,v) be the capacity and f(u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Heuristic (computer Science)
A heuristic or heuristic technique (''problem solving'', ''Heuristic (psychology), mental shortcut'', ''rule of thumb'') is any approach to problem solving that employs a Pragmatism, pragmatic method that is not fully Mathematical optimisation, optimized, perfected, or Rationality, rationalized, but is nevertheless "good enough" as an approximation or attribute substitution. Where finding an optimal solution is impossible or impractical, heuristic methods can be used to speed up the process of finding a satisfactory solution. Heuristics can be mental shortcuts that ease the cognitive load of Decision-making, making a decision. Context Gigerenzer & Gaissmaier (2011) state that Set (mathematics), sub-sets of ''strategy'' include heuristics, regression analysis, and Bayesian inference. Heuristics are strategies based on rules to generate optimal decisions, like the anchoring effect and utility maximization problem. These strategies depend on using readily accessible, thoug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
OSPF
Open Shortest Path First (OSPF) is a routing protocol for Internet Protocol (IP) networks. It uses a link state routing (LSR) algorithm and falls into the group of interior gateway protocols (IGPs), operating within a single autonomous system (AS). OSPF gathers link state information from available routers and constructs a topology map of the network. The topology is presented as a routing table to the internet layer for routing packets by their destination IP address. OSPF supports Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6) networks and is widely used in large enterprise networks. IS-IS, another LSR-based protocol, is more common in large service provider networks. Originally designed in the 1980s, OSPF version 2 is defined in RFC 2328 (1998). The updates for IPv6 are specified as OSPF version 3 in RFC 5340 (2008). OSPF supports the Classless Inter-Domain Routing (CIDR) addressing model. Concepts OSPF is an interior gateway protocol (IGP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Diffusing Update Algorithm
The diffusing update algorithm (DUAL) is the algorithm used by Cisco's EIGRP routing protocol to ensure that a given route is recalculated globally whenever it might cause a routing loop. It was developed by J.J. Garcia-Luna-Aceves at SRI International. The full name of the algorithm is DUAL finite-state machine (DUAL FSM). EIGRP is responsible for the routing within an autonomous system, and DUAL responds to changes in the routing topology and dynamically adjusts the routing tables of the router automatically. EIGRP uses a feasibility condition to ensure that only loop-free routes are ever selected. The feasibility condition is conservative: when the condition is true, no loops can occur, but the condition might under some circumstances reject all routes to a destination although some are loop-free. When no feasible route to a destination is available, the DUAL algorithm invokes a diffusing computation to ensure that all traces of the problematic route are eliminated from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
EIGRP
Enhanced Interior Gateway Routing Protocol (EIGRP) is an advanced distance-vector routing protocol that is used on a computer network for automating routing decisions and configuration. The protocol was designed by Cisco Systems as a proprietary protocol, available only on Cisco routers. In 2013, Cisco permitted other vendors to freely implement a limited version of EIGRP with some of its associated features such as High Availability (HA), while withholding other EIGRP features such as EIGRP stub, needed for DMVPN and large-scale campus deployment. Information needed for implementation was published with informational status as in 2016, which did not advance to Internet Standards Track level, and allowed Cisco to retain control of the EIGRP protocol. EIGRP is used on a router to share routes with other routers within the same autonomous system. Unlike other well known routing protocols, such as RIP, EIGRP only sends incremental updates, reducing the workload on the router and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
IGRP
Interior Gateway Routing Protocol (IGRP) is a distance vector interior gateway protocol (IGP) developed by Cisco. It is used by routers to exchange routing data within an autonomous system. IGRP is a proprietary protocol. IGRP was created in part to overcome the limitations of RIP (maximum hop count of only 15, and a single routing metric) when used within large networks. IGRP supports multiple metrics for each route, including bandwidth, delay, load, and reliability; to compare two routes these metrics are combined into a single metric, using a formula which can be adjusted through the use of pre-set constants. By default, the IGRP composite metric is a sum of the segment delays and the lowest segment bandwidth. The maximum configurable hop count of IGRP-routed packets is 255 (default 100), and routing updates are broadcast every 90 seconds (by default). IGRP uses protocol number 9 for communication.{{cite web , url=https://www.iana.org/assignments/protocol-numbers/protocol-n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Heuristic
A heuristic or heuristic technique (''problem solving'', '' mental shortcut'', ''rule of thumb'') is any approach to problem solving that employs a pragmatic method that is not fully optimized, perfected, or rationalized, but is nevertheless "good enough" as an approximation or attribute substitution. Where finding an optimal solution is impossible or impractical, heuristic methods can be used to speed up the process of finding a satisfactory solution. Heuristics can be mental shortcuts that ease the cognitive load of making a decision. Context Gigerenzer & Gaissmaier (2011) state that sub-sets of ''strategy'' include heuristics, regression analysis, and Bayesian inference. Heuristics are strategies based on rules to generate optimal decisions, like the anchoring effect and utility maximization problem. These strategies depend on using readily accessible, though loosely applicable, information to control problem solving in human beings, machines and abstract i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
