ort 3/5 allowed vlans modified to 100. Finally, a show trunk will show you the status of the trunks. As you can see, only VLAN 100 is now allowed on trunk 3/5: Switch-2# (enable) sho trunk * - indicates vtp domain mismatch # - indicates dot1q-all-tagged enabled on the port $ - indicates non-default dot1q-ethertype value Encapsulation Status Native vlan dot1q trunking nonegotiate trunking nonegotiate isl trunking Vlans allowed on trunk 1-4094 1-4094 Vlans allowed and active in management domain Vlans in spanning tree forwarding state and not pruned Chapter 5: Trunking 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 num- bers can be managed at central devices, with the resulting configuration distributed automatically 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 that 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 every switch. Sure, you can copy the whole thing into a text file, and paste it into each of the switches, but the process still won't be fun. Look at the VLAN names. There are two warehouses, a lab, a main office-this is a big place! You'll have to haul a laptop and a cons