VTP

[jonk34567]

To VTP to function properly the domain name and Password ( if configured ) must be matched.what about the version number ?

[paul driver · Accepted solution]

Hello

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@jonk34567 wrote:

To VTP to function properly the domain name and Password ( if configured ) must be matched.what about the version number ?

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 The version numbers also need to be the same when functioning same domain

res

Paul

[Georg Pauwen]

Hello,

I stand corrected: only VTP passwords are optional.

One addition: VTP version 3 does require a domain.

VTP versions need to match. Whatever is configured on your VTP server will be propagated to the VTP client.

[Julio E. Moisa]

Hi

Usually the version number is inhereted from the vtp server to the client vtp switches, you cannot modify the version if your switch is configured as client.  

:-)

[paul driver]

Hello

@Julio E. Moisa 

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@Julio E. Moisa wrote:

Hi

Usually the version number is inhereted from the vtp server to the client vtp switches, you cannot modify the version if your switch is configured as client.  

:-)

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The caveat to that would be its only inherited on switches that support vtp2 so if you have switches that don’t support vtp2 then it’s advisable  not to enable ver 2 (which nowadays I guess there is very little devices not able to support it)

res

Paul

[Julio E. Moisa]

@paul driver

Good point, yes that is correct, the last time I configured VTP was on Cisco 3750, If Im not wrong they also support all the versions. 

Thanks Paul. 

[Predrag Jovic]

List of rules can be pretty long and can be found in switch documentation, for example, here: VTP Configuration Guidelines

Quote from the page:

VTP Version

Follow these guidelines when deciding which VTP version to implement:

• All switches in a VTP domain must have the same domain name, but they do not need to run the same VTP version.

• A VTP version 2-capable switch can operate in the same VTP domain as a switch running VTP version 1 if version 2 is disabled on the version 2-capable switch (version 2 is disabled by default).

• If a switch running VTP version 1 but capable of running VTP version 2 receives VTP version 3 advertisements, it automatically moves to VTP version 2.

• 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 4094). 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.

[Georg Pauwen]

Good post ! That pretty much sums it up...