has not yet been connected to the network. It is a VTP client with a configuration revision of 2 and knows of seven VLANs. Switch2#show vtp status
VTP Version : 2
Configuration Revision : 2
Maximum VLANs supported locally : 250
Number of existing VLANs : 7
VTP Operating Mode : Client
VTP Domain Name : building1
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x7C 0x2A 0x2B 0xF1 0x2C 0x90 0x5D 0xB2
Configuration last modified by 172.16.1.11 at 3-1-93 00:34:17
The link between Switch1 and Switch2 is now connected and the VTP client overwrites the VTP server because of the higher configuration revision number. Switch1#
00:43:47: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/1, changed state to up

Switch1#show vtp status
VTP Version : 2
Configuration Revision : 2
Maximum VLANs supported locally : 1005
Number of existing VLANs : 7
VTP Operating Mode : Server
VTP Domain Name : building1
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x7C 0x2A 0x2B 0xF1 0x2C 0x90 0x5D 0xB2
Configuration last modified by 172.16.1.11 at 3-1-93 00:34:17
Local updater ID is 172.16.1.111 on interface Vl1 (lowest numbered VLAN interface found) To avoid a VTP domain from being overwritten always add a new switch either in VTP transparent mode or as a VTP client with a revision number that is lower than the revision number in the existing VTP domain.

Content 2.5 Correcting Common VLAN Configuration Errors 2.5.6 Best Practice for VTP Configuration Following is a list of general best practices with regard to configuring VTP in the enterprise composite network model:

Plan boundaries for the VTP domain. Not all switches in the network need information on all VLANs in the network. In the enterprise composite model, the VTP domain should be restricted to redundant distribution switches and the access switches that they serve.
Have only one or two switches specifically configured as VTP servers and the remainder as clients.
Configure a password so that no switch can join the VTP domain with a domain name only (which can be derived dynamically).
Manually configure the VTP domain name on all switches that are installed in the network so that the mode can be specified and the default server mode on all switches can be overwritten.
When you are setting up a new domain, configure VTP client switches first so that they participate passively. Then configure servers to update client devices.
In an existing domain, if you are performing VTP cleanup, configure passwords on servers first. Clients may need to maintain current VLAN information until the server contains a complete VLAN database. After the VLAN database on the server is verified as complete, client passwords can be configured to be the same as the servers. Clients will then accept updates from the server.

Content 2.6 VLAN Lab Exercises 2.6.1 Lab 2-0 Clearing a Switch
Lab Activity Lab Exercise: Lab 2-0a Clearing a Switch The purpose of this lab is to clear a switch and prepare it for a new lab. Lab Activity Lab Exercise: Lab 2-0b Clearing a Switch Connected to a Larger Network The purpose of this lab is to clear a switch that is connected to other switches and prepare it for a new lab. Note: It is required that the student study the commands covered in the module using the labs and the Command Reference. Not all required commands are covered in sufficient detail in the text alone. Successful completion of this course requires a thorough knowledge of command syntax and application. The Command Reference can be found on the Cisco.com website at the following URL:
http://www.cisco.com/en/US/products/ ps6441/prod_command_ reference_list.html

Content 2.6 VLAN Lab Exercises 2.6.2 Lab 2-1 Catalyst 2960 and 3560 Series Static VLANS, VLAN Trunking, and VTP Domain and Modes Lab Activity Lab Exercise: Lab 2-1 Catalyst 2960 and 3560 Series Static VLANS, VLAN Trunking, and VTP Domain and Modes Set up a VTP domain, create and maintain VLANs, and use Inter-Switch Link (ISL) and 802.1Q trunking on Cisco Catalyst 2960 and 3560 series Ethernet switches using command-line interface (CLI) mode.

Content Summary This module examined the function of VLANs and how they are implemented in a switched campus network. Depending on its configuration as an access or trunk port, each switch port can be associated with one or many VLANs. The ISL and 802.1Q protocols are used to establish trunk links carrying traffic for multiple VLANs. Trunk links between switches can also carry VTP information, which allows VLAN names and descriptions contained in a VLAN database to be shared between switches.