Scenario routing and Switching
You have three routers (R1, R2, R3) connected with serial links, running routing. You have three switches (SW1, SW2, SW3) connected with EtherChannel (LACP). PCs A, B, C are connected to switches with VLAN 1 IP addresses. VLAN interfaces (SVI) are configured on the switches with IPs in the 172.16.x.x ranges. Your Question: “Can I add one interface into 2 VLANs?” Looking at your design: Ports like F0/6 (PC-A) , F0/18 (PC-B) , F0/18 (PC-C) are access ports . 👉 These cannot belong to two VLANs at once. Each port is tied to only one VLAN . Your switch interconnects (F0/1, F0/2, F0/3, F0/4) are bundled in an EtherChannel (trunk) . 👉 Here, you can allow multiple VLANs to pass through (e.g., VLAN 10, VLAN 20), but the frames are tagged so each belongs to a single VLAN at a time . If you want PC-A in VLAN 10 and VLAN 20 , that’s not possible with one NIC . But if the PC had a second NIC (or supported VLAN tagging in its OS), then you could connect it ...
