Preventing Traffic Loss

On the network shown in Figure 1, AGG_Switch_A and AGG_Switch_B back up each other, and several ACC_Switches are dual-homed to the two AGG_Switches to implement load balancing. If all the links between AGG_Switch_A and the core network fail, only the links between AGG_Switch_B and the core network are available on the network side. However, ACC_Switches cannot detect link failures and still forward packets destined for the core network to AGG_Switch_A. In this scenario, the packets transmitted from ACC_Switches are lost because all the links between AGG_Switch_A and the core network are unavailable.

To prevent traffic loss, you can configure route monitoring groups on ACC_Switches to quickly detect the connectivity of IP routes on the network. This will allow ACC_Switches to promptly perform access-side link switching when there are changes to the status of IP routes.

Figure 1 Typical networking diagram of route monitoring groups