Heuristic routing - AbsoluteAstronomy.com

Heuristic

Heuristic refers to experience-based techniques for problem solving, learning, and discovery. Heuristic methods are used to speed up the process of finding a satisfactory solution, where an exhaustive search is impractical...

is an adjective used in relation to methods of learning, discovery, or problem solving.
Routing

Routing

Routing is the process of selecting paths in a network along which to send network traffic. Routing is performed for many kinds of networks, including the telephone network , electronic data networks , and transportation networks...

is the process of selecting paths to specific destinations.

According to Schuster (1974):
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 constitutes an acceptable solution is part of the task of deciding which approach to use; but broadly defined, an acceptable solution is one that is both reasonably good (close to optimum) and derived within reasonable effort, time, and cost constraints. Often the effort (manpower, computer, and other resources) required, the time limits on when the solution is needed, and the cost to compile, process, and analyze all the data required for deterministic or other complicated procedures preclude their usefulness or favor the faster, simpler heuristic approach.
Thus, the heuristic approach is generally used when deterministic techniques or are not available, economical, or practical. (p.9)

Heuristic Routing is a system used to describe how data is delivered when problems in a network topology arise. Heuristic routing is achieved using specific algorithms to determine the best, although not always optimal, path to a destination. When an interruption in a network topology

Network topology

Network topology is the layout pattern of interconnections of the various elements of a computer or biological network....

occurs, the software running on the networking electronics calculates another route to the desired destination via an alternate available path.

Heuristic routing is also used for vehicular traffic using the highway and transportation network

Transportation network

Transportation network may refer to:* Transport network, physical infrastructure* Transportation network , the mathematical graph theory...

of the world, but that is beyond the scope of this article.

Heuristic routing: Routing

Routing

in which data

Data

The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...

, such as time

Time

Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....

delay

Network delay

Network delay is an important design and performance characteristic of a computer network or telecommunications network. The delay of a network specifies how long it takes for a bit of data to travel across the network from one node or endpoint to another. It is typically measured in multiples or...

, extracted from incoming messages, during specified periods and over different routes, are used to determine the optimum routing for transmitting data back to the sources.

Note: Heuristic routing allows a measure of route optimization based on recent empirical knowledge of the state of the network

Telecommunications network

A telecommunications network is a collection of terminals, links and nodes which connect together to enable telecommunication between users of the terminals. Networks may use circuit switching or message switching. Each terminal in the network must have a unique address so messages or connections...

.

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IP Routing

The routing protocols in use today are based on one of two algorithms: Distance Vector or Link State. Distance Vector algorithms broadcast routing information to all neighboring routers. Link State routing protocols build a topographical map of the entire network based on updates from neighbor routers, and then use the Dijkstra algorithm to compute the shortest path to each destination.
Metrics used are based on the number of hops, delay, throughput, traffic, and reliability.

Distance Vector

RIP

Routing Information Protocol

The Routing Information Protocol is a distance-vector routing protocol, 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 the source to a destination. The maximum number of hops allowed for RIP is 15....

uses number of hops, or gateways traversed, as its metric.

IGRP uses bandwidth, delay, hop count, link reliability, load, and MTU

MTU

MTU may refer to:Networks and Internet* Maximum transmission unit, the size of the largest packet that a network protocol can transmit* Multi tenant unit, a telecom term referring to a building with multiple offices or apartments...

.

EIGRP uses the (DUAL) Diffusing Update Algorithm

Diffusing update algorithm

DUAL, the Diffusing Update ALgorithm, 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. According to Cisco, the full name of the...

.

BGP uses the Distance Vector algorithm

Link State

OSPF uses the Dijkstra algorithm.

IP Routing

See also