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Metrics (networking)

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(Redirected from Routing metric) Field in a routing table used to make routing decisions For other uses, see Metric (disambiguation).
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Routing metrics are configuration values used by a router to make routing decisions. A metric is typically one of many fields in a routing table. Router metrics help the router choose the best route among multiple feasible routes to a destination. The route will go in the direction of the gateway with the lowest metric.

A router metric is typically based on information such as path length, bandwidth, load, hop count, path cost, delay, maximum transmission unit (MTU), reliability and communications cost.

Examples

A metric can include:

In EIGRP, metrics is represented by an integer from 0 to 4,294,967,295 (The size of a 32-bit integer). In Microsoft Windows XP routing it ranges from 1 to 9999.

A metric can be considered as:

  • additive - the total cost of a path is the sum of the costs of individual links along the path,
  • concave - the total cost of a path is the minimum of the costs of individual links along the path,
  • multiplicative - the total cost of a path is the product of the costs of individual links along the path.

Service level metrics

Router metrics are metrics used by a router to make routing decisions. It is typically one of many fields in a routing table.

Router metrics can contain any number of values that help the router determine the best route among multiple routes to a destination. A router metric is typically based on information like path length, bandwidth, load, hop count, path cost, delay, MTU, reliability and communications cost.

See also

  • Administrative distance, indicates the source of routing table entry and is used in preference to metrics for routing decisions

References

  1. Rao, S. Dharma; Murthy, C. Siva Ram (2005). "Distributed dynamic QoS-aware routing in WDM optical networks". Computer Networks. 48 (4): 585–604. doi:10.1016/j.comnet.2004.11.003.
  2. "Administrative Distance and Metric". Archived from the original on 2021-11-22. Retrieved 2021-12-23.
  3. "Understand the significance of administrative distance and metrics when working with routers". 19 May 2005. Archived from the original on 2021-12-23. Retrieved 2021-12-23.
  4. "Administrative distance & metric". 26 January 2016. Archived from the original on 2021-12-23. Retrieved 2021-12-23.

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