title: Metrics (networking)
text: # Metrics (networking)
  
  Router 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:
  
  * measuring link utilization (using SNMP)
  * number of hops (hop count)
  * speed of the path
  * packet loss (router congestion/conditions)
  * Network delay
  * path reliability
  * path bandwidth
  * throughput [SNMP - query routers]
  * load
  * Maximum transmission unit (MTU)
  * administrator configured value
  
  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 typically based on information like path length, bandwidth, load, hop count, path cost, delay, MTU, reliability and communications cost.
  
  