There is a delay issue with WSG accessing the public network

Refer to the blow topology:

The customer is complaining that WSG1812X-PWR is causing some service interruptions especially for video conference. Ping to the internet is not stable from our equipment, sometimes with long RTT and even with some packet losses.

Customer testing shows that S5120V3 accessing the public network and gateway has no delay, and Router accessing the public network and gateway is normal, but there is a delay when WSG accesses the gateway.

WSG ping 8.8.8.8:

WSG ping gateway:

S5120V3 ping gateway:

Firstly, the customer's version is relatively low. It is recommended that the customer upgrade to the next version first, but there is still a delay issue after the upgrade.

Then the CPU, memory, processes, etc. of the device were checked and no abnormalities were found:

After checking the forwarding process, it is relatively high, but theoretically there should be no delay, so it is suspected that the occasional high traffic caused it; it can be seen that all GE ports of AC are up, it should be all connected to the device, which is different from the networking description, all traffic needs to be forwarded by AC, so it is recommended that other devices connected to AC can be connected to SW, then, it is currently possible to consider changing to local forwarding, and then doing second-layer isolation based on VLAN.

The issue was solved after several APs were moved to Switch from AC.