cisco ccna 200 301 study guide

cisco ccna 200 301 study guide.Router(config)# router eigrp autonomous_system_# Router(config-router)# traffic-share balancedRouter(config-router)# traffic-share min across-interfacesThe first command specifies that the default load balancing behavior be adopted, which was described in the previous paragraph. The min argument tells the router to add non-equal overhead paths to the routing table, but the router will not use these routes unless the best route fails. This is used in situations where you do not want to use non-optimal connections (they may be slower connections, such as dial-up connections) and also want to ensure fast convergence-the secondary path is already in the routing table when the primary path fails.Chapter 20 EIGRP Routing 533Note that additional paths to the destination network can be added to the IP routing table by using the variance feature. This way, when a path fails, there are alternate paths in the routing table, so convergence is almost instantaneous. If you want the router to use only the best path, but want to add the alternate path to the routing table, use the command traffic-share min across-interfacesoWhen testing load balancing on a router, be sure not to use ping or traceroute, as exchanging these packets uses process switching rather than fast switching (CEF switching), which can lead to confusing load balancing test results: test every possible path. It is best to perform this test on other devices behind the load balancing router.AggregationEIGRP automatically aggregates routes at classified network boundaries, as shown in the top half of Figure 20.2. For example, if a router is connected to a subnet of 172.16.0.0/16 and is also connected to another network, such as 192.168.1.0/24, EIGRP will advertise the route 172.16.0.0/16 outbound on the interface belonging to network 192.168.1.0/24, but not the subnet of 172.16.0.0/16. If the network is split into two parts (172.16.1.0/24 and 172.16.2.0/24) separated by network 192.168.1.0/24, this causes reachability problems because 172.16.0.0/16 will be advertised on both network boundaries. such problems are discussed in Chapter 7.To disable automatic summarization, use the following configuration.Router(config)# router eigrp autonomous_system_# Router(config-router)# no auto-summary