Description: The ‘Feasible Successor’ in EIGRP (Enhanced Interior Gateway Routing Protocol) is a backup route that can be used if the primary route fails. This concept is fundamental for ensuring high availability and resilience in networks. A Feasible Successor is a route that meets certain viability criteria, meaning it has a lower metric cost than the primary route and is available for immediate use. Unlike other routing protocols that may require convergence time to find a new route, EIGRP allows the use of Feasible Successors almost instantaneously, minimizing downtime in the network. This feature is based on the DUAL (Diffusing Update Algorithm), which enables EIGRP to calculate and maintain multiple routes to a destination, ensuring that there is always an alternative ready to be used. The implementation of Feasible Successors not only improves routing efficiency but also optimizes network resource usage, as it allows traffic to be directed through secondary routes without needing to recalculate the network topology in case of failures. In summary, the Feasible Successor is a key tool in modern network management, providing an effective solution to maintain connectivity and stability in complex network environments.
History: EIGRP was developed by Cisco in the 1990s as an advanced routing protocol that combines features of distance vector and link-state protocols. The concept of Feasible Successor was introduced to improve routing efficiency and reduce convergence time compared to other routing protocols of the time.
Uses: The Feasible Successor is primarily used in enterprise networks that require high availability and resilience. It allows network administrators to configure backup routes that automatically activate in case of failures, thus ensuring service continuity.
Examples: A practical example of using Feasible Successors can be seen in a corporate network where multiple links are used to connect different branches. If the primary link fails, traffic is automatically redirected through a Feasible Successor, preventing communication disruptions.
