Dynamic routing

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Dynamic routing, also called adaptive routing, [1] [2] 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. [3] 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. [4] Dynamic routing allows as many routes as possible to remain valid in response to the change.

Contents

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 its destination and give up the journey. [5]

All protocols

There are several routing protocols that can be used for dynamic routing. Routing Information Protocol (RIP) is a distance-vector routing protocol that prevents routing loops by implementing a limit on the number of hops allowed in a path from source to destination. [6] Open Shortest Path First (OSPF) uses a link state routing (LSR) algorithm and falls into the group of interior gateway protocols (IGPs). [7] Intermediate System to Intermediate System (IS-IS) determines the best route for data through a packet-switched network. [7] Interior Gateway Routing Protocol (IGRP) and its advanced form Enhanced Interior Gateway Routing Protocol (EIGRP) are used by routers to exchange routing data within an autonomous system. [7]

Alternate paths

Many systems use some next-hop forwarding protocol—when a packet arrives at some node, that node decides on-the-fly which link to use to push the packet one hop closer to its final destination.

Routers that use some adaptive protocols, such as the Spanning Tree Protocol, in order to "avoid bridge loops and routing loops", calculate a tree that indicates the one "best" link for a packet to get to its destination. Alternate "redundant" links not on the tree are temporarily disabled—until one of the links on the main tree fails, and the routers calculate a new tree using those links to route around the broken link.

Routers that use other adaptive protocols, such as grouped adaptive routing, find a group of all the links that could be used to get the packet one hop closer to its final destination. The router sends the packet out any link of that group which is idle. The link aggregation of that group of links effectively becomes a single high-bandwidth connection. [8]

Outside of computer networks

Contact centres employ dynamic routing based on the customer's enquiry and agent's skills to increase the operational efficiency of the call handling by agents, which boosts both agent and customer satisfaction. This adaptive strategy is known as omnichannel. [9]

Dynamic routing in found the brain in relation between sensory and mnemonic signals and decision making, and is a subject of studies in neuroscience. [10]

People using public transport also exhibit dynamic routing behaviour. For example, if a local railway station is closed, people can alight from the train at a different station and use a bus to reach their destination.

See also

Related Research Articles

The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.

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 identify established paths between endpoints. MPLS can encapsulate packets of various network protocols, hence the multiprotocol component of the name. MPLS supports a range of access technologies, including T1/E1, ATM, Frame Relay, and DSL.

<span class="mw-page-title-main">Router (computing)</span> Device that forwards data packets between computer networks

A router is a computer and networking device that forwards data packets between computer networks, including internetworks such as the global Internet.

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.

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.

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).

<span class="mw-page-title-main">Routing table</span> Data table stored in a router that lists the routes to network destinations

In computer networking, a routing table, or routing information base (RIB), is a data table stored in a router or a network host that lists the routes to particular network destinations, and in some cases, metrics (distances) associated with those routes. The routing table contains information about the topology of the network immediately around it.

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 RFC 7868 in 2016, which did not advance to Internet Standards Track level, and allowed Cisco to retain control of the EIGRP protocol.

In the seven-layer OSI model of computer networking, the network layer is layer 3. The network layer is responsible for packet forwarding including routing through intermediate routers.

A distance-vector routing protocol in data networks determines the best route for data packets based on distance. Distance-vector routing protocols measure the distance by the number of routers a packet has to pass; one router counts as one hop. Some distance-vector protocols also take into account network latency and other factors that influence traffic on a given route. To determine the best route across a network, routers using a distance-vector protocol exchange information with one another, usually routing tables plus hop counts for destination networks and possibly other traffic information. Distance-vector routing protocols also require that a router inform its neighbours of network topology changes periodically.

Link-state routing protocols are one of the two main classes of routing protocols used in packet switching networks for computer communications, the others being distance-vector routing protocols. Examples of link-state routing protocols include Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS).

<span class="mw-page-title-main">Wireless mesh network</span> Radio nodes organized in a mesh topology

A wireless mesh network (WMN) is a communications network made up of radio nodes organized in a mesh topology. It can also be a form of wireless ad hoc network.

<span class="mw-page-title-main">Optimized Link State Routing Protocol</span> IP routing protocol optimized for mobile ad hoc networks

The Optimized Link State Routing Protocol (OLSR) is an IP routing protocol optimized for mobile ad hoc networks, which can also be used on other wireless ad hoc networks. OLSR is a proactive link-state routing protocol, which uses hello and topology control (TC) messages to discover and then disseminate link state information throughout the mobile ad hoc network. Individual nodes use this topology information to compute next hop destinations for all nodes in the network using shortest hop forwarding paths.

Dynamic Source Routing (DSR) is a routing protocol for wireless mesh networks. It is similar to AODV in that it forms a route on-demand when a transmitting node requests one. However, it uses source routing instead of relying on the routing table at each intermediate device.

<span class="mw-page-title-main">B.A.T.M.A.N.</span> Routing protocol for multi-hop mobile ad hoc networks

The Better Approach to Mobile Ad-hoc Networking (B.A.T.M.A.N.) is a routing protocol for multi-hop mobile ad hoc networks which is under development by the German "Freifunk" community and intended to replace the Optimized Link State Routing Protocol (OLSR) as OLSR did not meet the performance requirements of large-scale mesh deployments.

A routing protocol specifies how routers communicate with each other to distribute information that enables them to select paths between nodes on a computer network. Routers perform the traffic directing functions on the Internet; data packets are forwarded through the networks of the internet from router to router until they reach their destination computer. Routing algorithms determine the specific choice of route. Each router has a prior knowledge only of networks attached to it directly. A routing protocol shares this information first among immediate neighbors, and then throughout the network. This way, routers gain knowledge of the topology of the network. The ability of routing protocols to dynamically adjust to changing conditions such as disabled connections and components and route data around obstructions is what gives the Internet its fault tolerance and high availability.

In wired computer networking a hop occurs when a packet is passed from one network segment to the next. Data packets pass through routers as they travel between source and destination. The hop count refers to the number of network devices through which data passes from source to destination.

IEEE 802.1aq is an amendment to the IEEE 802.1Q networking standard which adds support for Shortest Path Bridging (SPB). This technology is intended to simplify the creation and configuration of Ethernet networks while enabling multipath routing.

IP routing is the application of routing methodologies to IP networks. This involves not only protocols and technologies but includes the policies of the worldwide organization and configuration of 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 in an IP network. The process uses static configuration rules or dynamically obtained from 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, a total path potentially spanning multiple computer networks.

In a router, route redistribution allows a network that uses one routing protocol to route traffic dynamically based on information learned from another routing protocol.

References

  1. ↑ Terrence Mak; Peter Y. K. Cheung; Kai-Pui Lam; and Wayne Luk. "Adaptive Routing in Network-on-Chips Using a Dynamic-Programming Network". 2011. doi : 10.1109/TIE.2010.2081953 p. 1.
  2. ↑ Lugones, Diego; Franco, Daniel; Luque, Emilio (2008). "Dynamic Routing Balancing On InfiniBand Networks" (PDF). Journal of Computer Science and Technology. 8 (2). Archived from the original (PDF) on 6 May 2015.
  3. ↑ Haiyong Xie; Lili Qiu; Yang Richard Yang; and Yin Zhang. "On Self Adaptive Routing in Dynamic Environments — An Evaluation and Design Using a Simple, Probabilistic Scheme" Archived 2011-09-02 at the Wayback Machine . 2004.
  4. ↑ "Definition of". PC.
  5. ↑ "Static and Dynamic Routers". TechNet.
  6. ↑ "Dynamic routing with RIP". Tech Republic.
  7. 1 2 3 "Comparing Dynamic Routing Protocols". Network Computing.
  8. ↑ Stefan Haas. "The IEEE 1355 Standard: Developments, Performance and Application in High Energy Physics". 1998. p. 91.
  9. ↑ "Best Practices for Contact Center Routing". Genesys. Archived from the original on 2018-05-02. Retrieved 2017-11-18.
  10. ↑ "Dynamic routing of task-relevant signals for decision making in dorsolateral prefrontal cortex". Nature.
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