VTP

[Roel Reyes]

I'm confused regarding vtp, they said vtp 1 and 2 doesn't support extended vlans,

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/15-1SY/config_guide/sup2T/15_1_sy_swcg_2T/vtp.pdf

Support for extended range VLAN database propagation—VTP version 1 and version 2 support VLANs 1 to 1000 only. In VTP version 3, the entire VLAN range is supported (VLANs 1 to 4094). The pruning of VLANs still applies to VLANs 1 to 1000 only. Extended-range VLANs are supported in VTP version 3 only. Private VLANs are supported in VTP version 3. If you convert from VTP version 3 to VTP version 2, the VLANs in the range 1006 to 4094 are removed from VTP control.

then, 

VTP version 1 and VTP version 2 do not propagate configuration information for extended-range VLANs (VLAN numbers 1006 to 4094). You must configure extended-range VLANs manually on each network device.

In VTP versions 1 and 2, the switch must be in VTP transparent mode when you create extended-range VLANs. VTP version 3 also supports creating extended-range VLANs in client or server mode.

Pleases explain. Thanks

[Georg Pauwen]

Hello,

switches in VTP transparent mode actually do not participate in VTP, they simply forward VTP advertisements out their trunks. So what that means is that a switch in transparent mode, running VTP version 1 and 2, can forward VTP advertisements coming from VTP version 3 (and thus carrying extended Vlan information), but extended Vlans cannot be created on switches running version 1 or 2, only 3.

Does that make sense ?

[Roel Reyes]

but how will you understand this line?

VTP version 1 and VTP version 2 do not propagate configuration information for extended-range VLANs (VLAN numbers 1006 to 4094). You must configure extended-range VLANs manually on each network device. 

does it mean vtp 1 and 2, doesn't forward extended vlans unless you configure vtp mode to transparent? 

[Georg Pauwen · Accepted solution]

Hello,

consider the following scenario:

Switch 1 (VTP version 3) --> Switch 2 (VTP version 1/2) --> Switch 3 (VTP version 3)

Now let's say you create Vlan 2000 on Switch 1. That Vlan would not be propagated to Switch 2 or Switch 3, because Switch 2 runs VTP version 1 or 2. To make this work, you either configure Switch 2 for VTP transparent mode, which effectively means Switch 2 does not participate in VTP at all and simply passes on whatever it gets through the trunks. Or, obviously, you can configure Switch 2 for VTP version 3 as well.

If you leave Switch 2 as is (running VTP version 1 or 2), the only way to get Vlan 2000 information onto Switch 2 and Switch 3 is by manually configuring that Vlan on both Switch 2 and Switch 3.

Does that make sense ?