High CPU usage when S series switch functions as a DHCP relay agent
When an S series switch functions as a DHCP relay agent, multiple VLANs need to be configured on the switch so that the switch can forward DHCP Request messages of clients on multiple network segments. When the switch receives a DHCP Request message from a client, it traverses all VLANs to find the VLAN ID and determine the gateway address of the client. Too large a VLAN ID uses excessive CPU resources, resulting in a high CPU usage.
In actual networking, do not allocate IP addresses on many IP network segments to clients when a switch is used as a DHCP relay agent, and fewer VLAN IDs should be used. To assign IP addresses to a large number of clients, configure multiple DHCP relay agents.