 VLAN IDs of the allowed VLANs when this port in trunking Add VLANs to the current list All VLANs except All VLANs except the following No VLANs remove Remove VLANs from the current list This works similarly to the IOS version of the command. Here, if we allow VLAN 100, all other VLANs are prohibited. NX-7K-1-Cozy(config-if)# switchport trunk allowed vlan 100 You can see which VLANs are allowed over the trunk with the show interface trunk command. The output of the command differs from IOS, but the information is all there. NX-7K-1-Cozy(config-if)# sho int trunk Native Status Channel Eth3/2 trunking Eth8/1 trnk-bndl Eth8/2 trnk-bndl trunking Vlans Allowed on Trunk Eth3/2 Eth8/1 1-3967, 4048-4093 Eth8/2 1-3967, 4048-4093 1-3967, 4048-4093 Vlans Err-disabled on Trunk Eth3/2 Eth8/1 Eth8/2 STP Forwarding Eth3/2 Eth8/1 Eth8/2 Configuring Trunks CHAPTER 6 VLAN Trunking Protocol In complex networks, managing VLANs can be time-consuming and error-prone. The VLAN Trunking Protocol (VTP) is a means whereby VLAN names and numbers can be managed at central devices, with the resulting configuration distributed automati- cally to other devices. Take, for example, the network shown in Figure 6-1. This typical three-tier network is composed completely of Layer-2 switches. There are 12 switches in all: 2 in the core, 4 in the distribution layer, and 6 in the access layer (a real network employing this design might have hundreds of switches). Figure 6-1. Three-tier switched network Let's assume the network has 10 VLANs throughout the entire design. That's not SO bad, right? Here's what a 10-VLAN configuration might look like on a 2950: vlan 10 name IT vlan 20 name Personnel vlan 30 name Accounting vlan 40 name Warehouse1 vlan 50 name Warehouse2 vlan 60 name Shipping vlan 70 name MainOffice vlan 80 name Receiving vlan 90 name Lab vlan 100 name Production Now, consider that every switch in the design needs to have information about every VLAN. To accomplish this, you'll need to enter these commands exactly the same each time into ev