Description: Path Cost is a metric used in the EIGRP (Enhanced Interior Gateway Routing Protocol) routing protocol to determine the best path to a destination in a network. This metric is based on several factors, including bandwidth, latency, load, and link reliability. Unlike other routing protocols that may use a single metric, EIGRP combines multiple parameters to calculate a total cost, allowing for a more accurate assessment of available routes. The Path Cost is expressed as a numerical value, where a lower value indicates a preferred route. This metric is fundamental for routing decision-making, as it enables routers to select the most efficient path and optimize data traffic across the network. Additionally, EIGRP employs a DUAL (Diffusing Update Algorithm) that allows for rapid convergence and network stability, ensuring that changes in topology are efficiently reflected in routing decisions. In summary, Path Cost is an essential component of EIGRP’s operation, providing an effective way to evaluate and select routes in complex network environments.
History: EIGRP was developed by Cisco in the 1990s as an enhancement over the IGRP (Interior Gateway Routing Protocol). The introduction of Path Cost as a metric was part of this effort to create a more efficient and flexible routing protocol capable of adapting to the changing needs of modern networks. Since its release, EIGRP has evolved and become a de facto standard in many organizations, especially in environments using Cisco equipment.
Uses: Path Cost is primarily used in enterprise networks implementing EIGRP to optimize data routing. It allows network administrators to define routing policies based on link performance, ensuring that traffic is directed through the most efficient paths. It is also used in network capacity planning, helping to identify bottlenecks and improve service quality.
Examples: A practical example of using Path Cost can be seen in a corporate network where multiple links of varying capacities are used. When configuring EIGRP, the administrator can adjust cost parameters to prioritize traffic through higher bandwidth links, ensuring a better experience for users. Another example is in redundancy implementation, where Path Cost can help determine which link to use in case one fails.
