© Copyright Lenovo 2016 Chapter 9: VLANs 163Note: VLAN tagging/trunk mode is required only on ports that are connected toother switches or on ports that connect to tag‐capable end‐stations, such as serverswith VLAN‐tagging/trunk mode adapters.To configure a specific VLAN on a trunk port, the following conditions must bemet: The port must be in trunk mode. The VLAN must be in the trunk’s allowed VLAN range. By default, the rangeincludes all VLANs. The VLAN must be un‐reserved. The VLAN must be created.The order in which these conditions are met is not relevant. However, allconditions must be met collectively. When all the conditions are met, the VLAN isenabled on the port. If one of the conditions is broken, the VLAN is disabled.Table 14. Multiple VLANs ExampleComponent DescriptionG8264 switch This switch is configured with three VLANs that representthree different IP subnets. Five ports are connecteddownstream to servers. Two ports are connected upstream torouting switches. Uplink ports are members of all threeVLANs, with VLAN tagging/trunk mode enabled.Server 1 This server is a member of VLAN 1 and has presence in onlyone IP subnet. The associated switch port is only a member ofVLAN 1, so tagging/trunk mode is disabled.Server 2 This server is a member of VLAN 1 and has presence in onlyone IP subnet. The associated switch port is only a member ofVLAN 1, so tagging/trunk mode is disabled.Server 3 This server belongs to VLAN 2, and it is logically in the sameIP subnet as Server 5. The associated switch port hastagging/trunk mode disabled.Server 4 A member of VLAN 3, this server can communicate only withother servers via a router. The associated switch port hastagging/trunk mode disabled.Server 5 A member of VLAN 1 and VLAN 2, this server cancommunicate only with Server 1, Server 2, and Server 3. Theassociated switch port has tagging/trunk mode enabled.EnterpriseRoutingswitchesThese switches must have all three VLANs (VLAN 1, 2, 3)configured. They can communicate with Server 1, Server 2,and Server 5 via VLAN 1. They can communicate withServer 3 and Server 5 via VLAN 2. They can communicatewith Server 4 via VLAN 3. Tagging/trunk mode on switchports is enabled.
