1-3The disadvantage of using static routes is that they cannot adapt to network topology changes. If a faultor a topology change occurs to the network, the routes may be unreachable and the network maybreak.To avoid such problems, you can configure another route to back up the static route and use the AutoDetect function to judge the validity of the static route. If the static route is valid, packets are forwardedaccording to the static route, and the other route is standby. If the static route is invalid, packets areforwarded according to the backup route. In this way, the communication is not interrupted, and thenetwork reliability is improved.You can bind the static route with a detected group. The Auto Detect function will then detect the groupand judge the validity of the static route according to the returned reachable/unreachable information..z The static route is valid if the detected group is reachable.z The static route is invalid if the detected group is unreachable.You need to create the detected group before performing the following operations.Follow these steps to configure the auto detect function for a static route:To do… Use the command… RemarksEnter system view system-view —Bind a detected group toa static routeip route-static ip-address { mask | mask-length }{ interface-type interface-number | next-hop }[ preference preference-value ] [ reject |blackhole ] detect-group group-numberRequiredAuto Detect Implementation in VRRPCurrently, auto detect implementation in VRRP is only supported on S3600-EI series Ethernet switches.Virtual Router Redundancy Protocol (VRRP) is a fault-tolerant protocol. It assigns a set of switchesacting as gateways to a backup group, which forms a virtual switch. Switches in the backup group electa master switch based on priorities to take the responsibility of traffic forwarding. The other switchesoperate as backup switches. When the master switch fails, a backup switch takes over to forward traffic,thus guaranteeing the hosts in the network can communicate with the external network uninterruptedlythrough the virtual switch.However, when the uplink of a switch fails, the backup group cannot sense the uplink failure. If theuplink of the master switch fails, the hosts in the LAN cannot access the external network, as shown inFigure 1-1.
