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Configuring VTP
Information About Configuring VTP
If a switch running VTP version 3 is connected to a switch running VTP version 1, the VTP version 1 switch moves
to VTP version 2, and the VTP version 3 switch sends scaled-down versions of the VTP packets so that the VTP
version 2 switch can update its database.
A switch running VTP version 3 cannot move to version 1 or 2 if it has extended VLANs.
Do not enable VTP version 2 on a switch unless all of the switches in the same VTP domain are version-2-capable.
When you enable version 2 on a switch, all of the version-2-capable switches in the domain enable version 2. If there
is a version 1-only switch, it does not exchange VTP information with switches that have version 2 enabled.
We recommend placing VTP version 1 and 2 switches at the edge of the network because they do not forward VTP
version 3 advertisements.
If there are TrBRF and TrCRF Token Ring networks in your environment, you must enable VTP version 2 or version 3
for Token Ring VLAN switching to function properly. To run Token Ring and Token Ring-Net, disable VTP version 2.
VTP version 1 and version 2 do not propagate configuration information for extended range VLANs (VLANs 1006 to
4096). You must configure these VLANs manually on each device. VTP version 3 supports extended-range VLANs.
You cannot convert from VTP version 3 to VTP version 2 if extended VLANs are configured.
When a VTP version 3 device 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 VTP version 2 format. A VTP version 3 device does not send
VTP version 2-formatted packets on a trunk unless it first receives VTP version 2 packets on that trunk port.
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 both kinds of neighbors to coexist on the same trunk.
A VTP version 3 device does not accept configuration information from a VTP version 2 or version 1 device.
Two VTP version 3 regions can only communicate in transparent mode over a VTP version 1 or version 2 region.
Devices that are only VTP version 1 capable cannot interoperate with VTP version 3 devices.
VTP version 2 and version 3 are disabled by default.
When you enable VTP version 2 on a switch, every VTP version 2-capable switch in the VTP domain enables
version 2. To enable VTP version 3, you must manually configure it on each switch.
With VTP versions 1 and 2, you can configure the version only on switches in VTP server or transparent mode. If a
switch is running VTP version 3, you can change to version 2 when the switch is in client mode if no extended VLANs
exist, no private VLANs exist, and no hidden password was configured.
Caution:
In VTP version 3, both the primary and secondary servers can exist on an instance in the domain.
VTP Pruning
VTP pruning increases network available bandwidth by restricting flooded traffic to those trunk links that the traffic must
use to reach the destination devices. Without VTP pruning, a switch floods broadcast, multicast, and unknown unicast
traffic across all trunk links within a VTP domain even though receiving switches might discard them. VTP pruning is
disabled by default.
VTP pruning blocks unneeded flooded traffic to VLANs on trunk ports that are included in the pruning-eligible list. Only
VLANs included in the pruning-eligible list can be pruned. By default, VLANs 2 through 1001 are pruning eligible switch
trunk ports. If the VLANs are configured as pruning-ineligible, the flooding continues. VTP pruning is supported in all VTP
versions.
shows a switched network without VTP pruning enabled. Port 1 on Switch A and Port 2 on Switch
D are assigned to the Red VLAN. If a broadcast is sent from the host connected to Switch A, Switch A floods the
broadcast and every switch in the network receives it, even though Switches C, E, and F have no ports in the Red VLAN.
Summary of Contents for IE 4000
Page 12: ...8 Configuration Overview Default Settings After Initial Switch Configuration ...
Page 52: ...48 Configuring Interfaces Monitoring and Maintaining the Interfaces ...
Page 108: ...104 Configuring Switch Clusters Additional References ...
Page 128: ...124 Performing Switch Administration Additional References ...
Page 130: ...126 Configuring PTP ...
Page 140: ...136 Configuring CIP Additional References ...
Page 146: ...142 Configuring SDM Templates Configuration Examples for Configuring SDM Templates ...
Page 192: ...188 Configuring Switch Based Authentication Additional References ...
Page 244: ...240 Configuring IEEE 802 1x Port Based Authentication Additional References ...
Page 298: ...294 Configuring VLANs Additional References ...
Page 336: ...332 Configuring STP Additional References ...
Page 408: ...404 Configuring DHCP Additional References ...
Page 450: ...446 Configuring IGMP Snooping and MVR Additional References ...
Page 490: ...486 Configuring SPAN and RSPAN Additional References ...
Page 502: ...498 Configuring Layer 2 NAT ...
Page 770: ...766 Configuring IPv6 MLD Snooping Related Documents ...
Page 930: ...926 Configuring IP Unicast Routing Related Documents ...
Page 976: ...972 Configuring Cisco IOS IP SLAs Operations Additional References ...
Page 978: ...974 Dying Gasp ...
Page 990: ...986 Configuring Enhanced Object Tracking Monitoring Enhanced Object Tracking ...
Page 994: ...990 Configuring MODBUS TCP Displaying MODBUS TCP Information ...
Page 996: ...992 Ethernet CFM ...
Page 1066: ...1062 Using an SD Card SD Card Alarms ...