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Routing Algorithms
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 route ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Network Theory
In mathematics, computer science, and network science, network theory is a part of graph theory. It defines networks as Graph (discrete mathematics), graphs where the vertices or edges possess attributes. Network theory analyses these networks over the symmetric relations or directed graph, asymmetric relations between their (discrete) components. Network theory has applications in many disciplines, including statistical physics, particle physics, computer science, electrical engineering, biology, archaeology, linguistics, economics, finance, operations research, climatology, ecology, public health, sociology, psychology, and neuroscience. Applications of network theory include Logistics, logistical networks, the World Wide Web, Internet, gene regulatory networks, metabolic networks, social networks, epistemological networks, etc.; see List of network theory topics for more examples. Euler's solution of the Seven Bridges of Königsberg, Seven Bridges of Königsberg problem is c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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IP Routing
IP routing is the application of traffic routing methodologies to IP networks. This involves technologies, protocols, structure, administrations, and policies of the worldwide Internet infrastructure. In each IP network node, IP routing involves the determination of a suitable path for a network packet from a source to its destination. The process uses rules, obtained from either static configuration or dynamically with routing protocols, to select specific packet forwarding methods to direct traffic to the next available intermediate network node one ''hop'' closer to the desired final destination. The total path potentially spans multiple computer networks. Networks are separated from each other by specialized hosts, called gateways or routers with specialized software support optimized for routing. IP forwarding algorithms in most routing software determine a route through a shortest path algorithm. In routers, packets arriving at an interface are examined for source and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Shortest Paths
In graph theory, the shortest path problem is the problem of finding a path between two vertices (or nodes) in a graph such that the sum of the weights of its constituent edges is minimized. The problem of finding the shortest path between two intersections on a road map may be modeled as a special case of the shortest path problem in graphs, where the vertices correspond to intersections and the edges correspond to road segments, each weighted by the length or distance of each segment. Definition The shortest path problem can be defined for graphs whether undirected, directed, or mixed. The definition for undirected graphs states that every edge can be traversed in either direction. Directed graphs require that consecutive vertices be connected by an appropriate directed edge. Two vertices are adjacent when they are both incident to a common edge. A path in an undirected graph is a sequence of vertices P = ( v_1, v_2, \ldots, v_n ) \in V \times V \times \cdots \times V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Graph (discrete Mathematics)
In discrete mathematics, particularly in graph theory, a graph is a structure consisting of a Set (mathematics), set of objects where some pairs of the objects are in some sense "related". The objects are represented by abstractions called ''Vertex (graph theory), vertices'' (also called ''nodes'' or ''points'') and each of the related pairs of vertices is called an ''edge'' (also called ''link'' or ''line''). Typically, a graph is depicted in diagrammatic form as a set of dots or circles for the vertices, joined by lines or curves for the edges. The edges may be directed or undirected. For example, if the vertices represent people at a party, and there is an edge between two people if they shake hands, then this graph is undirected because any person ''A'' can shake hands with a person ''B'' only if ''B'' also shakes hands with ''A''. In contrast, if an edge from a person ''A'' to a person ''B'' means that ''A'' owes money to ''B'', then this graph is directed, because owing mon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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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] |
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Enhanced Interior Gateway Routing Protocol
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] |
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Open Shortest Path First
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 (Internet), 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 Network service provider, 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. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Routing Information Protocol
The Routing Information Protocol (RIP) is one of the oldest distance-vector routing protocols which employs the hop count as a routing metric. RIP prevents routing loops by implementing a limit on the number of hops allowed in a path from source to destination. The largest number of hops allowed for RIP is 15, which limits the size of networks that RIP can support. RIP implements the split horizon, route poisoning, and holddown mechanisms to prevent incorrect routing information from being propagated. In RIPv1 routers broadcast updates with their routing table every 30 seconds. In the early deployments, routing tables were small enough that the traffic was not significant. As networks grew in size, however, it became evident there could be a massive traffic burst every 30 seconds, even if the routers had been initialized at random times. In most networking environments, RIP is not the preferred choice of routing protocol, as its time to converge and scalability are poo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Dynamic Routing
In computer networking, dynamic routing (DR), also called adaptive routing (AR), is a process where a router can forward data via a different route for a given destination based on the current conditions of the communication circuits within a system. The term is most commonly associated with data networking to describe the capability of a network to 'route around' damage, such as loss of a node or a connection between nodes, as long as other path choices are available. Dynamic routing allows as many routes as possible to remain valid in response to the change. Systems that do not implement dynamic routing are described as using static routing, where routes through a network are described by fixed paths. A change, such as the loss of a node, or loss of a connection between nodes, is not compensated for. This means that anything that wishes to take an affected path will either have to wait for the failure to be repaired before restarting its journey, or will have to fail to reach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Routing In The PSTN
Routing in the PSTN is the process of forwarding telephone calls between the constituent telephone networks that comprise the public switched telephone network (PSTN). Telephone calls are routed across a network of potentially many switching systems, often owned by different telephone carriers. Switching systems are connected with trunks. Each switch may have many neighbors. Neighboring switches owned by different operators are connected at interconnect points. The PSTN is a network that uses destination routing to direct calls from origin to the recipient. It is not a full mesh network with the nodes of every operator directly connected to those of every other, which would be impractical and inefficient. Therefore, calls may be routed through intermediate operator networks before they reach their final destination. Efficient least-cost routing is an important procedure in PSTN routing. Call routing Each time a call is placed for routing, the destination number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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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] |
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Static Routing
Static routing describes a process by which routing is configured with fixed values that do not change at runtime unless manually edited. Static routes are used with and without dynamic Routing protocols and usually share the same routing table as those protocols. Routes require at least two attributes; the destination and the gateway, but may contain additional attributes such as a metric (sometimes called the ''administrative distance''). Some implementations treat the network address and subnet mask as separate values, however in practice both of the values have to be considered for any given routing decision to determine the longest prefix match. Static routes together with ''connected'' routes and routes from configuration protocols such as DHCP or Router Advertisements provide the routes which are then redistributed using dynamic routing protocols. While static routes are entered into the system and remain there until removed or changed manually, dynamic routing protocol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |