Lab - Configure VLANs and Trunking
Topology
Addressing Table
Device
Interface
IP Address
Subnet Mask
Default Gateway
S1
VLAN 1
192.168.1.11
255.255.255.0
N/A
S2
VLAN 1
192.168.1.12
255.255.255.0
N/A
PC-A
NIC
192.168.10.3
255.255.255.0
192.168.10.1
PC-B
NIC
192.168.10.4
255.255.255.0
192.168.10.1
Objectives
Part 1: Build the Network and Configure Basic Device Settings
Part 2: Create VLANs and Assign Switch Ports
Part 3: Maintain VLAN Port Assignments and the VLAN Database
Part 4: Configure an 802.1Q Trunk between the Switches Part
5: Delete the VLAN Database
Background / Scenario
Modern switches use virtual local-area networks (VLANs) to improve network performance by separating
large Layer 2 broadcast domains into smaller ones. VLANs can also be used as a security measure by
controlling which hosts can communicate. In general, VLANs make it easier to design a network to
support the goals of an organization.
VLAN trunks are used to span VLANs across multiple devices. Trunks allow the traffic from multiple VLANS to
travel over a single link, while keeping the VLAN identification and segmentation intact.
In this lab, you will create VLANs on both switches in the topology, assign VLANs to switch access ports,
verify that VLANs are working as expected, and then create a VLAN trunk between the two switches to
allow hosts in the same VLAN to communicate through the trunk, regardless of which switch the host is
actually attached to.
Note: The switches used with CCNA hands-on labs are Cisco Catalyst 2960s with Cisco IOS Release 15.2(2)
(lanbasek9 image). Other routers, switches, and Cisco IOS versions can be used. Depending on the model
and Cisco IOS version, the commands available and the output produced might vary from what is shown in
the labs. Refer to the Router Interface Summary Table at the end of the lab for the correct interface identifiers.
Lab - Configure VLANs and Trunking
Note: Ensure that the routers and switches have been erased and have no startup configurations. If you are
unsure contact your instructor.
Required Resources
• 2 Switches (Cisco 2960 with Cisco IOS Release 15.2(2) lanbasek9 image or comparable)
• 2 PCs (Windows with a terminal emulation program, such as Tera Term)
• Console cables to configure the Cisco IOS devices via the console ports
• Ethernet cables as shown in the topology
Instructions Part 1: Build the Network and Configure Basic Device Settings
In Part 1, you will set up the network topology and configure basic settings on the PC hosts and switches.
Step 1: Cable the network as shown in the topology.
Attach the devices as shown in the topology diagram, and cable as necessary.
Step 2: Configure basic settings for each switch.
a. Console into the switch and enable privileged EXEC mode.
b. Enter configuration mode.
c. Assign a device name to the switch.
d. Disable DNS lookup to prevent the router from attempting to translate incorrectly entered commands as
though they were host names.
e. Assign class as the privileged EXEC encrypted password.
f. Assign cisco as the console password and enable login.
g. Assign cisco as the vty password and enable login.
h. Encrypt the plaintext passwords.
i. Create a banner that warns anyone accessing the device that unauthorized access is prohibited.
j. Configure the IP address listed in the Addressing Table for VLAN 1 on the switch.
k. Shut down all interfaces that will not be used.
l. Set the clock on the switch.
m. Save the running configuration to the startup configuration file.
Step 3: Configure PC hosts.
Refer to the Addressing Table for PC host address information.
***Answer all the questions with ***
Step 4: Test connectivity.
Verify that the PC hosts can ping one another.
Note: It may be necessary to disable the PCs firewall to ping between PCs.
Can PC-A ping PC-B? Yes
Can PC-A ping S1? No
Lab - Configure VLANs and Trunking
Can PC-B ping S2? No
Can S1 ping S2? Yes
If you answered no to any of the above questions, why were the pings unsuccessful? Pings were
unsuccessful when trying to ping a device on a different subnet. For those pings to be successful, a default
gateway must exist to route traffic from one subnet to another.
Part 2: Create VLANs and Assign Switch Ports
In Part 2, you will create Management, Operations, Parking_Lot, and Native VLANs on both switches. You will
then assign the VLANs to the appropriate interface. The show vlan command is used to verify your
configuration settings.
Step 1: Create VLANs on the switches.
a. Create the VLANs on S1.
S1(config)# vlan 10
S1(config-vlan)# name Operations
S1(config-vlan)# vlan 20
S1(config-vlan)# name Parking_Lot
S1(config-vlan)# vlan 99
S1(config-vlan)# name Management
S1(config-vlan)# vlan 1000
S1(config-vlan)# name Native
S1(config-vlan)# end
b. Create the same VLANs on S2.
c. Issue the show vlan brief command to view the list of VLANs on S1.
S1# show vlan brief
VLAN
Name
Status
Ports
1
default
active
Fa0/1,
Fa0/5,
Fa0/2, Fa0/3, Fa0/4
Fa0/6, Fa0/7, Fa0/8
Fa0/9, Fa0/10, Fa0/11, Fa0/12
Fa0/13, Fa0/14, Fa0/15, Fa0/16
Fa0/17, Fa0/18, Fa0/19, Fa0/20
Fa0/21, Fa0/22, Fa0/23, Fa0/24
Gi0/1, Gi0/2
20 Parking_Lot active
active
1000 Native
active
99 Management
10 Operations active
Lab - Configure VLANs and Trunking
1002
fddi-default
act/unsup
1003
token-ring-default
act/unsup
1004
fddinet-default
act/unsup
1005
trnet-default
act/unsup
What is the default VLAN? VLAN 1
What ports are assigned to the default VLAN? All switch ports are assigned to VLAN 1 by default.
Step 2: Assign VLANs to the correct switch interfaces.
a. Assign VLANs to the interfaces on S1.
1) Assign PC-A to the Operation VLAN.
S1(config)# interface f0/6
S1(config-if)# switchport mode access S1(config-if)# switchport access vlan
10
2) Move the switch IP address VLAN 99.
S1(config)# interface vlan 1
S1(config-if)# no ip address
S1(config-if)# interface vlan 99
S1(config-if)# ip address 192.168.1.11 255.255.255.0
S1(config-if)# end
b. Issue the show vlan brief command and verify that the VLANs are assigned to the correct interfaces. c.
Issue the show ip interface brief command.
What is the status of VLAN 99? Explain. The status of VLAN 99 is up/down because the VLAN exists in
the database but down because the VLAN has not been assigned to an active port yet.
d. Assign PC-B to the Operations VLAN on S2.
e. Remove the IP address for VLAN 1 on S2.
f. Configure an IP address for VLAN 99 on S2 according to the Addressing Table.
g. Use the show vlan brief command to verify that the VLANs are assigned to the correct interfaces.
Is S1 able to ping S2? Explain. No, the Ip addresses for the switches now reside in VLAN 99.
Is PC-A able to ping PC-B? Explain. No, interface f0/1 is not assigned to VLAN 10 so VLAN 10 will not be
sent over.
Part 3: Maintain VLAN Port Assignments and the VLAN Database
In Part 3, you will change VLAN assignments to ports and remove VLANs from the VLAN database.
Lab - Configure VLANs and Trunking
Step 1: Assign a VLAN to multiple interfaces.
a. On S1, assign interfaces F0/11 – 24 to VLAN99.
S1(config)# interface range f0/11-24
S1(config-if-range)# switchport mode access
S1(config-if-range)# switchport access vlan 99
S1(config-if-range)# end
b. Issue the show vlan brief command to verify VLAN assignments.
c. Reassign F0/11 and F0/21 to VLAN 10.
d. Verify that VLAN assignments are correct.
Step 2: Remove a VLAN assignment from an interface.
a. Use the no switchport access vlan command to remove the VLAN 99 assignment to F0/24.
S1(config)# interface f0/24
S1(config-if)# no switchport access vlan
S1(config-if)# end
b. Verify that the VLAN change was made.
Which VLAN is F0/24 now associated with? VLAN 1
Step 3: Remove a VLAN ID from the VLAN database.
a. Add VLAN 30 to interface F0/24 without issuing the global VLAN command.
S1(config)# interface f0/24
S1(config-if)# switchport access vlan 30
% Access VLAN does not exist. Creating vlan 30
Note: Current switch technology no longer requires that the vlan command be issued to add a VLAN to
the database. By assigning an unknown VLAN to a port, the VLAN will be created and added to the VLAN
database.
b. Verify that the new VLAN is displayed in the VLAN table.
What is the default name of VLAN 30? VLAN0030
c. Use the no vlan 30 command to remove VLAN 30 from the VLAN database.
S1(config)# no vlan 30
S1(config)# end
d. Issue the show vlan brief command. F0/24 was assigned to VLAN 30.
After deleting VLAN 30 from the VLAN database, what VLAN is port F0/24 assigned to? What happens to
the traffic destined to the host attached to F0/24? When you delete a VLAN, any ports assigned to that
VLAN become inactive. Port f0/24 is still associated to VLSN 30, it is also inactive because it does not
exist in the VLAN database.
Lab - Configure VLANs and Trunking
e. Issue the no switchport access vlan command on interface F0/24.
f. Issue the show vlan brief command to determine the VLAN assignment for F0/24.
To which VLAN is F0/24 assigned? VLAN 1
Note: Before removing a VLAN from the database, it is recommended that you reassign all the ports
assigned to that VLAN.
Why should you reassign a port to another VLAN before removing the VLAN from the VLAN database?
The interfaces assigned to a VLAN that is the removed from the VLAN database become inactive and are
unavailable for use until they are reassigned to another VLAN.
Part 4: Configure an 802.1Q Trunk Between the Switches
In Part 4, you will configure interface F0/1 to use the Dynamic Trunking Protocol (DTP) to allow it to negotiate
the trunk mode. After this has been accomplished and verified, you will disable DTP on interface F0/1 and
manually configure it as a trunk.
Step 1: Use DTP to initiate trunking on F0/1.
The default DTP mode of a 2960 switch port is dynamic auto. This allows the interface to convert the link to a
trunk if the neighboring interface is set to trunk or dynamic desirable mode.
a. Set F0/1 on S1 to negotiate trunk mode.
S1(config)# interface f0/1
S1(config-if)# switchport mode dynamic desirable
Sep 19 02:51:47.257: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1,
changed state to up
Sep 19 02:51:47.291: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan99, changed
state to up
You should also receive link status messages on S2.
S2#
Sep 19 02:42:19.424: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up
Sep 19 02:42:21.454: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan99, changed
state to up
Sep 19 02:42:22.419: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1,
changed state to up
b. Issue the show vlan brief command on S1 and S2. Interface F0/1 is no longer assigned to VLAN 1.
Trunked interfaces are not listed in the VLAN table.
c. Issue the show interfaces trunk command to view trunked interfaces. Notice that the mode on S1 is set
to desirable, and the mode on S2 is set to auto.
S1# show interfaces trunk
S2# show interfaces trunk
Note: By default, all VLANs are allowed on a trunk. The switchport trunk command allows you to control
what VLANs have access to the trunk. For this lab, keep the default settings which allows all VLANs to
traverse F0/1.
d. Verify that VLAN traffic is traveling over trunk interface F0/1.
Lab - Configure VLANs and Trunking
Can S1 ping S2? Yes
Can PC-A ping PC-B? Yes
Can PC-A ping S1? No
Can PC-B ping S2? No
If you answered no to any of the above questions, explain below.
The switches are in VLAN 99 and the PCs are in VLAN 10, so the ping between VLANs were
unsuccessful.
Step 2: Manually configure trunk interface F0/1.
The switchport mode trunk command is used to manually configure a port as a trunk. This command should
be issued on both ends of the link.
a. Change the switchport mode on interface F0/1 to force trunking. Make sure to do this on both switches.
S1(config)# interface f0/1
S1(config-if)# switchport mode trunk
b. Issue the show interfaces trunk command to view the trunk mode. Notice that the mode changed from
desirable to on.
S2# show interfaces trunk
c. Modify the trunk configuration on both switches by changing the native VLAN from VLAN 1 to VLAN 1000.
S1(config)# interface f0/1
S1(config-if)# switchport trunk native vlan 1000
d. Issue the show interfaces trunk command to view the trunk. Notice the Native VLAN information is
updated.
S2# show interfaces trunk
Why might you want to manually configure an interface to trunk mode instead of using DTP? Not all
equipment uses DTP, using the switchport mode trunk command ensures that the port will become a
trunk no matter what type of equipment is connected to the other end of the link.
Why might you want to change the native VLAN on a trunk? Using VLAN 1 as the native VLAN is a
security risk. All the different control protocols that are exchanged between switches are exchanged by
the native VLAN 1 . The information could be exposed if default settings are used on ports that users
connect to.
Lab - Configure VLANs and Trunking
Reflection Questions
1. What is needed to allow hosts on VLAN 10 to communicate to hosts on VLAN 99? Allow inter VLAN routing
requires a layer 3 device which is needed to route traffic between VLANs.
2. What are some primary benefits that an organization can receive through effective use of VLANs? Better
security, higher performance, simpler project and cost savings.
***DO NOT DO THIS PART BEFORE SUBMITTING YOUR PACKET TRACER***
OPTIONAL: Part 5: Delete the VLAN Database
In Part 5, you will delete the VLAN Database from the switch. It is necessary to do this when initializing a
switch back to its default settings.
Step 1: Determine if the VLAN database exists.
Issue the show flash command to determine if a vlan.dat file exists in flash.
S1# show flash:
Note: If there is a vlan.dat file located in flash, then the VLAN database does not contain its default
settings.
Step 2: Delete the VLAN database.
a. Issue the delete vlan.dat command to delete the vlan.dat file from flash and reset the VLAN database
back to its default settings. You will be prompted twice to confirm that you want to delete the vlan.dat file.
Press Enter both times.
S1# delete vlan.dat
Delete filename [vlan.dat]?
Delete flash:/vlan.dat? [confirm]
b. Issue the show flash command to verify that the vlan.dat file has been deleted.
S1# show flash:
To initialize a switch back to its default settings, what other commands are needed?
