A switch issues a VTP advertisement request in these situations The switch has

A switch issues a vtp advertisement request in these

This preview shows page 28 - 33 out of 59 pages.

A switch issues a VTP advertisement request in these situations: The switch has been reset.The VTP domain name has been changed.The switch has received a VTP summary advertisement with a higher configuration revision than its own.Upon receipt of an advertisement request, a VTP device sends a summary advertisement.One or more subset advertisements follow the summary advertisement.
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Chapter 3 29 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public VTP AuthenticationVTP domains can be secured by using the VTP password feature. It is important to make sure that all the switches in the VTP domain have the same password and domain name; otherwise, a switch will not become a member of the VTP domain. Cisco switches use MD5 to encode passwords in 16-byte words. These passwords propagate inside VTP summary advertisements. In VTP, passwords are case-sensitive and can be 8 to 64 characters in length. The use of VTP authentication is a recommended practice. By default, a Catalyst switch does not have a VTP password. The switch does not automatically set the password parameter, unlike other parameters that are set automatically when a VTP advertisement is received.
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Chapter 3 30 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Configuring VTP Step 1. Enter global configuration mode: Switch# configure terminal Step 2. Configure the VTP mode as server: Switch(config)# vtp mode server Step 3. Configure the domain name: Switch(config)# vtp domain domain_name Step 4. (Optional.) Enable VTP version 2: Switch(config)# vtp version 2 Step 5. (Optional.) Specify a VTP password: Switch(config)# vtp password password_string Step 6. (Optional.) Enable VTP pruning in the management domain: Switch(config)# vtp pruning
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Chapter 3 31 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Verifying VTP Configuration (1) The most useful command for verifying VTP configuration is the show vtp status command. The output displayed includes the VTP version, the VTP configuration revision number, the number of VLANs supported locally, the VTP operating mode, the VTP domain name, and the VTP pruning mode. Switch# show vtp status VTP Version : 2 Configuration Revision : 247 Maximum VLANs supported locally : 1005 Number of existing VLANs : 33 VTP Operating Mode : Server VTP Domain Name : Modular_Form VTP Pruning Mode : Enabled VTP V2 Mode : Disabled VTP Traps Generation : Disabled MD5 digest : 0x45 0x52 0xB6 0xFD 0x63 0xC8 0x49 0x80 Configuration last modified by 0.0.0.0 at 8-12-99 15:04:4
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Chapter 3 32 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Verifying VTP Configuration (2) Use the show vtp counters command to display statistics about VTP operation. If there are any problems regarding the VTP operation, this command helps look for VTP message type updates. Switch# show vtp counters VTP statistics: Summary advertisements received : 7 Subset advertisements received : 5 Request advertisements received : 0 Summary advertisements transmitted : 997 Subset advertisements transmitted : 13 Request advertisements transmitted : 3
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