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Cisco Catalyst Blade Switch 3130 for Dell Software Configuration Guide
OL-13270-01
Chapter13 Configuring VTP
Understanding VTP
The switch supports 1005 VLANs, but the number of routed ports, SVIs, and other configured features
affects the usage of the switch hardware. If the switch is notified b y VTP o f a ne w VLAN a nd the switch
is already using the maximum available hardware resources, it sends a m essage that there are not enough
hardware resources available and shuts down the VLAN. The output of the show vlan user EXEC
command shows the VLAN in a suspended state.
VTP only learns about normal-range VLANs (VLAN IDs 1 to 100 5). E xte nde d-ra nge VLA Ns (VL AN
IDs greater than 1005) are not supported by VTP or stored in the VTP VLAN database.
These sections contain this conceptual information:
•The VTP Domain, page 13-2
•VTP Modes, page 13-3
•VTP Advertisements, page 13-3
•VTP Version 2, page13-4
•VTP Pruning, page 13-4
•VTP and Switch Stacks, page 13-6
The VTP Domain
A VTP domain (also called a VLAN management domain) consis ts of o ne sw itch or several
interconnected switches or switch stacks under the same administrative responsibility sharing the same
VTP domain name. A switch can be in only one VTP domain. You make global VLAN configuration
changes for the domain.
By default, the switch is in the VTP no-management-domain state until it receives an advertisement for
a domain over a trunk link (a link that carries the traffic of multiple VLANs) or until you configure a
domain name. Until the management domain name is specified or learned, you cannot create or modify
VLANs on a VTP server, and VLAN information is not propagated over the network.
If the switch receives a VTP advertisement over a trunk link, it inherits the management domain name
and the VTP configuration revision number. The switch then ignores advertisements with a different
domain name or an earlier configuration revision number.
Caution Before adding a VTP client switch to a 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.
Switches in a VTP domain always use the VLAN configuration of the swit ch w it h th e high est VTP
configuration revision number. If you add a switch that has a revision number hig he r th an the r evision
number in the VTP domain, it can erase all VLAN information from the VTP server and VTP domain.
See the “Adding a VTP Client Switch to a VTP Domain” section on page13-14 for the procedure for
verifying and resetting the VTP configuration revision number.
When you make a change to the VLAN configuration on a VTP server, the change is pr opa gated to a ll
switches in the VTP domain. VTP advertisements are sent over all IEEE trunk connections, including
Inter-Switch Link (ISL) and IEEE 802.1Q. VTP dynamically maps VLANs with unique names and
internal index associates across multiple LAN types. Mapping eliminates excessive device
administration required from network administrators.
If you configure a switch for VTP transparent mode, you can cr eate an d modify VLANs, b ut the chang es
are not sent to other switches in the domain, and they affect only the individual switch. However,
configuration changes made when the switch is in this mode ar e saved in the swi tch runni n g
configuration and can be saved to the switch startup configuration file.