Vtp Configuration Guidelines And Restrictions - Cisco Catalyst 4500 Series Configuration Manual

VLAN Trunking Protocol
Figure 15-3
Flooded traffic
is pruned.
Switch 6
Enabling VTP pruning on a VTP server enables pruning for the entire management domain. VTP pruning
takes effect several seconds after you enable it. By default, VLANs 2 through 1000 are eligible for
pruning. VTP pruning does not prune traffic from pruning-ineligible VLANs. VLAN 1 is always
ineligible for pruning; traffic from VLAN 1 cannot be pruned.
To configure VTP pruning on a trunking LAN interface, use the switchport trunk pruning vlan
command. VTP pruning operates when a LAN interface is trunking. You can set VLAN pruning
eligibility regardless of whether VTP pruning is enabled or disabled for the VTP domain, whether any
given VLAN exists, and regardless of whether the LAN interface is currently trunking.

VTP Configuration Guidelines and Restrictions

Follow these guidelines and restrictions when implementing VTP in your network:
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Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
15-12
Flooding Traffic with VTP Pruning
Switch 4
Interface 4
Switch 5 Interface 5
Switch 3
Supervisor engine redundancy does not support nondefault VLAN data file names or locations. Do
not enter the vtp file file_name command on a switch that has a redundant supervisor engine.
Before installing a redundant supervisor engine, enter the no vtp file command to return to the
default configuration.
When a VTP version 3 device on a trunk port receives messages from a VTP version 2 device, it
sends a scaled-down version of the VLAN database on that particular trunk in a VTP version 2
format. A VTP version 3 device does not send out VTP version 2 formatted packets on a trunk port
unless it first receives VTP version 2 packets on that trunk.
Even when a VTP version 3 device detects a VTP version 2 device on a trunk port, it continues to
send VTP version 3 packets in addition to VTP version 2 packets, to allow co-existence of two kinds
of neighbors off the trunk.
A VTP version 3 device does not accept configuration information from a VPT version 2 or
version 1 device.
Unlike in VPT version 2, when VTP is configured to be version 3, this does not configure all the
version-3-capable devices in the domain to start behaving as VPT version 3 systems.
When a VTP version 1 device, capable of version 2 or version 3, receives a VTP version 3 packet,
the device is configured as a VTP version 2 device provided a VTP version 2 conflict does not exist.
Devices that are only VTP version 1 capable cannot interoperate with VTP version 3 devices.
Interface 2
Switch 2
Red
VLAN
Interface 1
Switch 1
Chapter 15 Configuring VLANs, VTP, and VMPS
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