Description: The management distance in EIGRP (Enhanced Interior Gateway Routing Protocol) is a crucial value used to determine the reliability of a route in a network. This routing protocol, developed by Cisco, employs administrative distance to classify routes learned from different routing protocols. The management distance is expressed as a number, where a lower value indicates higher reliability. By default, EIGRP has an administrative distance of 90 for internal routes and 170 for external routes. This feature allows network administrators to make informed decisions about which routes to use for data traffic, prioritizing those that are more reliable. Additionally, management distance is fundamental in environments where multiple routing protocols coexist, as it helps prevent routing loops and optimizes network performance. In summary, management distance in EIGRP is an essential component that influences route selection and the overall stability of the network, ensuring that data is transmitted efficiently and reliably.
History: EIGRP was introduced by Cisco in 1993 as an enhancement of the Interior Gateway Routing Protocol (IGRP). Over the years, EIGRP has evolved to include advanced features such as the ability to perform multiprotocol routing and the implementation of a Diffusing Update Algorithm (DUAL) that improves network convergence. Administrative distance was established as a mechanism to help administrators manage the reliability of routes in this context.
Uses: Management distance is primarily used in network management to determine which routes should be preferred when multiple options are available. This is especially useful in environments where multiple routing protocols are implemented, as it allows administrators to set priorities and optimize data traffic. Additionally, management distance helps prevent routing loop issues and ensures network stability.
Examples: A practical example of management distance in EIGRP can be seen in a network that uses both EIGRP and OSPF (Open Shortest Path First). If EIGRP has an administrative distance of 90 and OSPF has one of 110, the routes learned through EIGRP will be preferred over those from OSPF. This allows network administrators to ensure that the most reliable routes are used for data traffic.
