200-301 exam cram

200-301 exam cram.3.2 Basic content 75Port Vlansinspanningtreeforwarding stateandnotpruned 3! SW2 next SW2# show interfaces trunk Port Mode Encapsulation GiO/1 auto 802.Iq GiO/2 auto 802.lq Port Vlans allowed on trunk GiO/1 1-4094 GiO/2 1-4094 Port Vlans allowed and active in GiO/1 1,3 GiO/2 1,3 Port Vlans in spanning tree forwarding state GiO/1 1,3 GiO/2 1 Status trunking trunking management Native vlan 1 1 domain and not prunedSW3 next SW3 next SW3# show , nterfaces trunk Port Mode Encapsulation GiO/1 auto 802.lq GiO/2 desirable 802.lq Port Zlans allowed on trunk GiO/1 1-4094 GiO/2 1- 4094 Port Vlans allowed and active in GiO/1 1,3 GiO/2 1,3 Port Vlans in spanning tree forwarding state GiO/1. 1,3 GiO/2 1,3 Status trunking trunking management Native vlan 1 1 domain and not prunedExample 3-14 (continued)In this example, first observe the final output of the three commands, with a focus on VLAN 3. It is observed that VLAN 3 is listed in the last VLAN list of all three switch trunk ports in this example, except for port G0/2 of SW2. Why did STP choose to block this port in VLAN3.Several different show spanning-tree commands can confirm that SW2's G0/2 port is blocked in VLAN3, but also infer from the output of this example that SW2's G0/2 port must be blocked. To do this, simply rule out that the other VLANs3 will not be packet76 Chapter 3 Troubleshooting LAN Switching bracketed in the show interfacestrunk command output list for this reason.In the show interface trunk command output for SW2, column 1 of the VLAN contains VLAN3,indicating that VLAN3 must be in the allowed list for that trunk.In the output of the show interface trunk command for SW2, column 2 of the VLAN contains VLAN3, indicating that VLAN3 is active on SW2.