ccna-s

ccna-s.Hybrid protocols have the simplicity of distance vector protocols while borrowing many of the features of link-state protocols, making them more efficient and scalable. Both EIGRP and BGP are hybrid protocols.Distance vector protocols suffer from convergence problems and routing loop problems. Convergence refers to the time it takes for all routers in the network to know the current topology. To increase the speed of convergence, triggered updates can be used. Routing loops are basically caused by inconsistent views of routers on how to travel to a particular network. To resolve infinite counting, a hop limit can be set to avoid packets being transmitted endlessly down the loop. Horizontal splitting is used to avoid the formation of small routing loops: it prohibits a router from re-announcing a route out of the interface where it was received.Routing suppression, reverse suppression, and suppression timers are used to prevent large routing loops from occurring. When a network connected to a router fails, routes to that network are suppressed. Reverse suppression lets the router advertise suppressed routes out of all interfaces, including the interface that received the suppressed route. The suppression timer keeps the suppressed route in the routing table, ensuring that the suppressed route is propagated to all routers before selecting a worse alternative path.Chapter 14 Routers and Routing 35114.5 Two-Minute SprintsIntroduction to Routing . The router learns about neighboring routers, finds out where the destination networks are located, selects the best path to each destination network, and maintains the routing table. . Static routes are manually configured routes. Directly connected routes are networks that are directly connected to the router interface.. An Autonomous System (AS) is a group of unified managed networks that can be an entire company, a division of a company, or multiple companies.. Administrative distance is a Cisco-specific mechanism for ranking IP routing protocols to help routers populate routing tables with the best path to the destination network. When running multiple routing protocols. the administrative distance determines which routing protocol routes are used to populate the routing table. The smaller the administrative distance, the higher the routing protocol priority.Dynamic routing protocols . When the same routing protocol learns of multiple paths to the same destination network, it uses metric values to select the best path.. Distance vector protocols (such as RIPvl) use distance and direction to find paths to a destination network and are known as routing based on anecdotal evidence. They broadcast periodic announcements of updates and do not establish formal relationships with other routers. They require little CPU cycles and memory because they simply add metric values and compare the results to routes already in the routing table. . -"