ACL configuration error
Symptom
ACL configuration error results in data flow blockage.
Analysis
When multiple devices create different IPsec tunnels early or late, a device may have multiple peers. If the device is not configured with ACL rule, the peers send packets to it to set up different IPsec tunnels in different protection granularity respectively. As the priorities of IPsec tunnels are determined by the order they are established, a device cannot interoperate with other peers in fine granularity when its outbound packets are first matched with an IPsec tunnel in coarse granularity.
Solution
When a device has multiple peers, configure ACLs on the device to distinguish different data flows and try to avoid configuring overlapping ACL rules for different peers. If it is unavoidable, the subrules in fine granularity should be configured with higher preferences.