2.1.4.4 Packet Tracer – Configure VLANs, VTP, and DTP Answers

2.1.4.4 Packet Tracer – Configure VLANs, VTP, and DTP Answers
3.5 (2) votes

Packet Tracer – Configure VLANs, VTP and DTP (Instructor Version)

Instructor Note: Red font color or gray highlights indicate text that appears in the instructor copy only.

Addressing Table

Objectives

Part 1: Configure and Verify DTP

Part 2: Configure and Verify VTP

Background / Scenario

As the number of switches in a network increases, the administration necessary to manage the VLANs and trunks can be challenging. To ease some of the VLAN and trunking configurations, VLAN trunking protocol (VTP) allows a network administration to automate the management of VLANs. Trunk negotiation between network devices is managed by the Dynamic Trunking Protocol (DTP), and is automatically enabled on Catalyst 2960 and Catalyst 3560 switches.

In this activity, you will configure trunk links between the switches. You will configure a VTP server and VTP clients in the same VTP domain. You will also observe the VTP behavior when a switch is in VTP transparent mode. You will assign ports to VLANs and verify end-to-end connectivity with the same VLAN.

Part 1: Configure and Verify DTP

In Part 1, you will configure trunk links among the switches, and you will configure VLAN 999 as the native VLAN.

Step 1: Verify VLAN configuration.

Verify the configured VLANs on the switches.

a.  On S1, click the CLI tab. At the prompt, enter enable and enter the show vlan brief command to verify the configured VLANs on S1.

VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4
Fa0/5, 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
Gig0/1, Gig0/2
99 Management active
999 VLAN0999 active
1002 fddi-default active
1003 token-ring-default active
1004 fddinet-default active
1005 trnet-default active

b.  Repeat step a. on S2 and S3. What VLANs are configured on the switches?

VLANs 99 and 999 are configured on all the switches.

Step 2: Configure Trunks on S1, S2, and S3.

Dynamic trunking protocol (DTP) manages the trunk links between Cisco switches. Currently all the switchports are in the default trunking mode, which is dynamic auto. In this step, you will change the trunking mode to dynamic desirable for the link between switches S1 and S2. For the link between switches S1 and S3, the link will be set as a static trunk. Use VLAN 999 as the native VLAN in this topology.

a.  On S1, configure the trunk link to dynamic desirable on the GigabitEthernet 0/1 interface.

S1(config)# interface g0/1
S1(config-if)# switchport mode dynamic desirable

b.  For the trunk link between S1 and S3, configure a static trunk link on the GigabitEthernet 0/2 interface.

S1(config)# interface g0/2
S1(config-if)# switchport mode trunk
S3(config)# interface g0/2
S3(config-if)# switchport mode trunk

c.  Verify trunking is enabled on all the switches using the show interfaces trunk command.

S1# show interfaces trunk
Port Mode Encapsulation Status Native vlan
Gig0/1 desirable n-802.1q trunking 1
Gig0/2 on 802.1q trunking 1
 
Port Vlans allowed on trunk
Gig0/1 1-1005
Gig0/2 1-1005
 
Port Vlans allowed and active in management domain
Gig0/1 1,99,999
Gig0/2 1,99,999
 
Port Vlans in spanning tree forwarding state and not pruned
Gig0/1 none
Gig0/2 none

What is the native VLAN for these trunks currently? VLAN 1

d.  Configure VLAN 999 as the native VLAN for the trunk links on S1.

S1(config)# interface range g0/1 - 2
S1(config-if-range)# switchport trunk native vlan 999

What messages did you receive on S1? How would you correct it?

%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet0/2 (999), with S3 GigabitEthernet0/2 (1).

%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet0/1 (999), with S2 GigabitEthernet0/1 (1).

To correct native VLAN mismatch, configure VLAN 999 as the native VLAN on S2 and S3.

e.  On S2 and S3, configure VLAN 999 as the native VLAN.

f.  Verify trunking is successfully configured on all the switches. You should be able ping one switch from another switch in the topology using the IP addresses configured on the SVI.

Part 2: Configure and Verify VTP

S1 will be configured as the VTP server and S2 will be configured as VTP clients. All the switches will be configured to be in the VTP domain CCNA and use the VTP password cisco.

VLANs can be created on the VTP server and distributed to other switches in the VTP domain. In this part, you will create 3 new VLANs on the VTP server, S1. These VLANs will be distributed to S2 using VTP. Observe how the transparent VTP mode behaves.

Step 1: Configure S1 as VTP server.

Configure S1 as the VTP server in the CCNA domain with the password cisco.

a.  Configure S1 as a VTP server.

S1(config)# vtp mode server
Setting device to VTP SERVER mode.

b.  Configure CCNA as the VTP domain name.

S1(config)# vtp domain CCNA
Changing VTP domain name from NULL to CCNA

c. Configure cisco as the VTP password.

S1(config)# vtp password cisco
Setting device VLAN database password to cisco

Step 2: Verify VTP on S1.

a.  Use the show vtp status command on the switches to confirm that the VTP mode and domain are configured correctly.

S1# show vtp status
VTP Version : 2
Configuration Revision : 0
Maximum VLANs supported locally : 255
Number of existing VLANs : 7
VTP Operating Mode : Server
VTP Domain Name : CCNA
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x8C 0x29 0x40 0xDD 0x7F 0x7A 0x63 0x17
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00
Local updater ID is 192.168.99.1 on interface Vl99 (lowest numbered VLAN interface found)

b. To verify the VTP password, use the show vtp password command.

S1# show vtp password
VTP Password: cisco

Step 3: Add S2 and S3 to the VTP domain.

Before S2 and S3 will accept VTP advertisements from S1, they must belong to the same VTP domain. Configure S2 and S3 as VTP clients with CCNA as the VTP domain name and cisco as the VTP password. Remember that VTP domain names are case sensitive.

a.  Configure S2 as a VTP client in the CCNA VTP domain with the VTP password cisco.

S2(config)# vtp mode client
Setting device to VTP CLIENT mode.
S2(config)# vtp domain CCNA
Changing VTP domain name from NULL to CCNA
S2(config)# vtp password cisco
Setting device VLAN database password to cisco

b.  To verify the VTP password, use the show vtp password command.

S2# show vtp password
VTP Password: cisco

c. Configure S3 to be in the CCNA VTP domain with the VTP password cisco. Switch S3 will stay in VTP transparent mode.

S3(config)# vtp domain CCNA
Changing VTP domain name from NULL to CCNA
S3(config)# vtp password cisco
Setting device VLAN database password to cisco

d. Enter show vtp status command on all the switches to answer the following question.

Notice that the configuration revision number is 0 on all three switches. Explain.

The configuration revision number increments by one every time a VLAN is added, deleted, or modified. No additional configurations have been made to VLANs on any of the switches.

Step 4: Create more VLANs on S1.

a.  On S1, create VLAN 10 and name it Red.

S1(config)# vlan 10
S1(config-vlan)# name Red

b.  Create VLANs 20 and 30 according to the table below.

c. Verify the addition of the new VLANs. Enter show vlan brief at the privileged EXEC mode.

Which VLANs are configured on S1?

VLANs 1, 10, 20, 30, 99, and 999.

d. Confirm configuration changes using the show vtp status command on S1 and S2 to confirm that the VTP mode and domain are configured correctly. Output for S2 is shown here:

S2# show vtp status
VTP Version : 2
Configuration Revision : 6
Maximum VLANs supported locally : 255
Number of existing VLANs : 10
VTP Operating Mode : Client
VTP Domain Name : CCNA
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0xE6 0x56 0x05 0xE0 0x7A 0x63 0xFB 0x33
Configuration last modified by 192.168.99.1 at 3-1-93 00:21:07

How many VLANs are configured on S2? Does S2 have the same VLANs as S1? Explain.

S2 has 10 VLANs, the same number as S1. Because S1 is the VTP server and S2 is a VTP client in the CCNA domain, S2 has received the VLAN information from S1.

Step 5: Observe VTP transparent mode.

S3 is currently configured as VTP transparent mode.

a.  Use show vtp status command to answer the following question.

How many VLANs are configured on S3 currently? What is the configuration revision number? Explain your answer.

Currently there are 7 VLANs on S3. The configuration revision number is 0 because S3 is in transparent mode and VLAN configurations have not been changed since switch startup.

How would you change the number of VLANs on S3?

While S3 is in transparent mode, it will not implement the VLAN information from the VTP server, so all of the VLANs changes either need to be configured manually, or S3 can be changed to a VTP client to implement the VLAN information from VTP server.

b.  Change VTP mode to client on S3.

Use show commands to verify the changes on VTP mode. How many VLANs exists on S3 now? 10

Note: VTP advertisements are flooded throughout the management domain every five minutes, or whenever a change occurs in VLAN configurations. To accelerate this process, you can switch between Realtime mode and Simulation mode until the next round of updates. However, you may have to do this multiple times because this will only forward Packet Tracer’s clock by 10 seconds each time. Alternatively, you can change one of the client switches to transparent mode and then back to client mode.

Step 6: Assign VLANs to Ports

Use the switchport mode access command to set access mode for the access links. Use the switchport access vlan vlan-id command to assign a VLAN to an access port.

a.  Assign VLANs to ports on S2 using assignments from the table above.

S2(config-if)# interface range f0/1 - 8
S2(config-if-range)# switchport mode access
S2(config-if-range)# switchport access vlan 10
S2(config-if-range)# interface range f0/9 -16
S2(config-if-range)# switchport mode access
S2(config-if-range)# switchport access vlan 20
S2(config-if-range)# interface range f0/17 - 24
S2(config-if-range)# switchport mode access
S2(config-if-range)# switchport access vlan 30

b.  Assign VLANs to ports on S3 using assignment from the table above.

Step 7: Verify end to end connectivity.

a.  From PC0 ping PC5.

b.  From PC1 ping PC4.

c.  From PC2 ping PC3.

Script

Switch S1

enable
config t
vtp mode server
vtp domain CCNA
vtp password cisco
vlan 10
 name Red
vlan 20
 name Blue
vlan 30
 name Yellow
interface g0/1
 switchport mode dynamic desirable
 switchport trunk native vlan 999
interface g0/2
 switchport mode trunk
 switchport trunk native vlan 999
end

Switches S2 and S3

enable
config t
vtp mode client
vtp domain CCNA
vtp password cisco
interface g0/1
switchport mode dynamic desirable
 switchport trunk native vlan 999
interface g0/2
switchport mode trunk
 switchport trunk native vlan 999
interface range f0/1 - 8
 switchport mode access
 switchport access vlan 10
interface range f0/9 - 16
 switchport mode access
 switchport access vlan 20
interface range f0/17 - 24
 switchport mode access
 switchport access vlan 30
end

Related Articles


Leave a Reply

avatar

Send this to a friend