Description: The ‘Query Response’ in EIGRP (Enhanced Interior Gateway Routing Protocol) refers to the response sent by a router to address a specific query regarding the status of a route or the existence of a route in the network topology. This mechanism is fundamental for the efficient operation of EIGRP, as it allows routers to exchange information about available routes and their current status. When a router needs information about a specific route, it sends a query to other routers in the network. The response to this query includes details about the requested route, such as its metric and status, enabling the router to make informed decisions about packet routing. This interaction is crucial for maintaining rapid convergence and network stability, as it ensures that all routers have an updated view of the network topology and can react appropriately to changes within it. The ‘Query Response’ is part of the EIGRP protocol, which combines features of distance vector and link-state protocols, making it efficient and robust in complex network environments.
History: EIGRP was developed by Cisco in 1993 as an advanced routing protocol that combines features of distance vector and link-state protocols. Originally, EIGRP was based on the IGRP (Interior Gateway Routing Protocol), which was also created by Cisco. Over time, EIGRP evolved to include significant improvements in convergence and routing efficiency, becoming a de facto standard in many enterprise networks.
Uses: EIGRP is primarily used in enterprise networks to facilitate efficient routing between multiple routers. Its ability to handle large network topologies and its rapid convergence make it ideal for environments where availability and performance are critical. Additionally, EIGRP supports both IPv4 and IPv6, making it a versatile option for various network implementations.
Examples: A practical example of ‘Query Response’ in EIGRP could be a router receiving a query about a specific route to a subnet. If the router has information about that route, it will send a response that includes the route’s metric and status, allowing the querying router to update its routing table. Another example would be in a network where a router detects a topology change and sends queries to other routers to verify the status of affected routes, receiving responses that enable it to adjust its routing efficiently.
