(1. Experimental objectives 1. Realize the VLAN isolation of the second-layer broadcast domain of the enterprise branch LAN and the connection of the whole network at the third layer. 2. Realize that the PC of the enterprise branch LAN uses DHCP to automatically obtain the IP address, DNS3, master vlan, trunk, and the network management address of the second-layer switch. Configuration of server vlan and SVI interface 4. Analyze the Layer 3 communication process and Layer 2 communication process of PC1pingSever (RT5))