VLANS and Trunking

Question 0

What is the IEEE protocol that defines how trunks should operate?

Answer 0

802.1q

Question 1

What are the two types of ports and their capabilities regarding VLANs?

Answer 1

Access ports - can only carry traffic on a single VLAN

Trunk ports - can carry traffic on multiple VLANs

Question 2

Describe the purpose and process of tagging traffic.

Answer 2

In order to identify a frame as belonging to a particular VLAN it needs to be “tagged”. A switch with a configured trunk port will add a tag to traffic that tells the connected switch which VLAN the traffic belongs to. The connected switch will remove the tag and forward the frame to the appropriate VLAN.

Question 3

You configure vlan 10 and name it SalesLan. What command would you use to assign interface fa0/1 (an access port) to this vlan?

Answer 3

Switch1(config-int)# switchport access vlan 10

Question 4

In an 802.1q frame, how long is the vlan tag?

Answer 4

12 bits

Question 5

Starting from the user prompt on Switch 1, create VLANs 10 and 20. VLAN 10 should be named “HR”, and VLAN 20 should be named “Sales”. Configure the fa0/0 interface as a trunk port and assign it both of these VLANs. Assign VLAN 999 as the native VLAN. Copy the running configuration to the NVRAM.

Answer 5

Switch1>enable
Switch1#conf t
Switch1(config)#vlan 10
Switch1(config-vlan)#name HR
Switch1(config-vlan)#exit
Switch1(config)#int fa0/0
Switch1(config-int)#switchport mode trunk
Switch1(config-int)#switchport trunk allowed vlan 10, 20
Switch1(config-int)#switchport trunk native vlan 999
Switch1(config-int)#exit
Switch1#copy running-config startup-config

Question 6

On Switch1 configure and name vlan 10 (students), vlan 20 (faculty), vlan 30 (administration), vlan 55 (native) and vlan 77(management). Give vlan 77 an IP address of 192.168.77.2 /24. Configure a default gateway of 192.168.77.1. Configure interface fa0/1 as a trunk port (using 802.1q encapsulation) and configure the native (55) and allowed vlans (10, 20, 30, 77).
Configure ports fa0/2, fa0/3 and fa0/4 as access ports and configure access vlans 10, 20 and 30, respectively.

Answer 6

Switch1>en
Switch1#conf t
Switch1(config)#vlan 10
Switch1(config-vlan)#name students
Switch1(config-vlan)#vlan 20
Switch1(config-vlan)#name faculty
Switch1(config-vlan)#vlan 30
Switch1(config-vlan)#name administration
Switch1(config-vlan)#vlan 55
Switch1(config-vlan)#name native
Switch1(config-vlan)#vlan 77
Switch1(config-vlan)#name management
Switch1(config-vlan)#int vlan 77
Switch1(config-int)#ip address 192.168.77.2 255.255.255.0
Switch1(config-int)#exit
Switch1(config)#ip default-gateway 192.168.77.1
Switch1(config)#int fa0/1
Switch1(config-int)#switchport mode trunk
Switch1(config-int)#switchport trunk encapsulation dot1q
Switch1(config-int)#switchport trunk native vlan 55
Switch1(config-int)#switchport trunk allowed vlan 10, 20, 30, 77
Switch1(config-int)#int fa0/2
Switch1(config-int)#switchport mode access
Switch1(config-int)#switchport access vlan 10
Switch1(config-int)#int fa0/3
Switch1(config-int)#switchport access vlan 20
Switch1(config-int)#int fa0/4
Switch1(config-int)#switchport access vlan 30