reaches that point, the counter will reset back to zero. There are two types of VTP advertisements: There are three types of VTP messages: With advertisement requests, clients request VLAN information and the server responds with summary and subset advertisements. By default, server and client Catalyst switches issue summary advertisements every five minutes. Servers inform neighbor switches what they believe to be the current VTP revision number. Assuming the domain names match, the receiving server or client compares the configuration revision number. If the revision number in the advertisement is higher than the current revision number in the receiving switch, the receiving switch then issues an advertisement request for new VLAN information. Subset advertisements contain detailed information about VLANs such as VTP version type, domain name and related fields, and the configuration revision number. The following can trigger these advertisements: Advertisements may contain some or all of the following information: Web Links Understanding and Configuring VLAN Trunk Protocol (VTP) http://www.cisco.com/en/US/tech/
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Content 9.2 VTP 9.2.5 VTP configuration The following basic tasks must be considered before configuring VTP and VLANs on the network.
  1. Determine the version number of VTP that will be utilized.
  2. Decide if this switch is to be a member of an existing management domain or if a new domain should be created. If a management domain exists, determine the name and password of the domain.
  3. Choose a VTP mode for the switch.
Two different versions of VTP are available, Version 1 and Version 2. The two versions are not interoperable. If a switch is configured in a domain for VTP Version 2, all switches in the management domain must be configured for VTP Version 2. VTP Version 1 is the default. VTP Version 2 may be implemented if some of the specific features that VTP Version 2 offers are not offered in VTP Version 1. The most common feature that is needed is Token Ring VLAN support. To configure the VTP version on a Cisco IOS command-based switch, first enter VLAN database mode. Use the following command to change the VTP version number on a set command-based switch. Switch#vlan database
Switch(vlan)#vtp v2-mode If the switch being installed is the first switch in the network, create the management domain. If the management domain has been secured, configure a password for the domain. To create a management domain use the following command: Switch(vlan)#vtp domain cisco The domain name can be between 1 and 32 characters. The password must be between 8 and 64 characters long. To add a VTP client to an existing VTP domain, always verify that its VTP configuration revision number is lower than the configuration revision number of the other switches in the VTP domain. Use the show vtp status command. Switches in a VTP domain always use the VLAN configuration of the switch with the highest VTP configuration revision number. If a switch is added that has a revision number higher than the revision number in the VTP domain, it can erase all VLAN information from the VTP server and VTP domain. Choose one of the three available VTP modes for the switch. If this is the first switch in the management domain and additional switches will be added, set the mode to server. The additional switches will be able to learn VLAN information from this switch. There should be at least one server. VLANs can be created, deleted, and renamed at will without the switch propagating changes to other switches. If a large number of people are configuring devices within the network, there is a risk of overlapping VLANs with two different meanings in the network but with the same VLAN identification. To set the correct mode of the Cisco IOS command-based switch, use the following command: Switch(vlan)#vtp {client | server | transparent} Figure shows the output of the show vtp status command. This command is used to verify VTP configuration settings on a Cisco IOS command-based switch. Figure shows an example of the show vtp counters command. This command is used to display statistics about advertisements sent and received on the switch. Lab Activity Lab Exercise: VTP Client and Server Configurations This lab is to configure the VTP protocol to establish server and client switches . Lab Activity e-Lab Activity: VTP Client and Server Configurations In this lab, the student will configure the VTP protocol to establish server and client switches . Web Links Multilayer Switching Commands http://www.cisco.com/univercd/cc/
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Content 9.3 Inter-VLAN Routing Overview 9.3.1 VLAN basics A VLAN is a logical grouping of devices or users that can be grouped by function, department, or application regardless of their physical location. VLANs are configured at the switch through software. The number of competing VLAN implementations can require the use of proprietary software from the switch vendor. Grouping ports and users into communities of interest, referred to as VLAN organizations, may be accomplished by the use of a single switch or more powerfully among connected switches within the enterprise. By grouping the ports and users together across multiple switches, VLANs can span single building infrastructures or interconnected buildings. VLANs assist in the effective use of bandwidth as they share the same broadcast domain or Layer 3 network. VLANs optimize the collection and use of bandwidth. VLANs contend for the same bandwidth although the bandwidth requirements may vary greatly by workgroup or department. The following are some VLAN configuration issues: VLANs help control the size of broadcast domains and localize traffic. VLANs are associated with individual networks. Therefore, network devices in different VLANs cannot directly communicate without the intervention of a Layer 3 routing device. When a node in one VLAN needs to communicate with a node in another VLAN, a router is necessary to route the traffic between VLANs. Without the routing device, inter-VLAN traffic would not be possible.
Content 9.3 Inter-VLAN Routing Overview 9.3.2 Introducing inter-VLAN routing When a host in one broadcast domain wishes to communicate with a host in another broadcast domain, a router must be involved. Port 1 on a switch is part of VLAN 1, and port 2 is part of VLAN 200. If all of the switch ports were part of VLAN 1, the hosts connected to these ports could communicate. In this case however, the ports are part of different VLANs, VLAN 1 and VLAN 200. A router must be involved if hosts from the different VLANs need to communicate. The most important benefit of routing is its proven history of facilitating networks, particularly large