Problem:
Some of the older documentation and study guides state that VTP domains don’t need to match when set to version 2 transparent.
“Version-dependent transparent mode; transparent mode no longer checks domain name. This enables support of more than one domain across a transparent domain.”
Some of the newer documentation states to the contrary.
“Version-Dependent Transparent Mode—In VTP version 1, a VTP transparent switch inspects VTP messages for the domain name and version and forwards a message only if the version and domain name match. Although VTP version 2 supports only one domain, a VTP version 2 transparent switch forwards a message only when the domain name matches.”
Verification:
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CORE01#sh vtp status
VTP Version : running VTP2
Configuration Revision : 14
Maximum VLANs supported locally : 1005
Number of existing VLANs : 17
VTP Operating Mode : Server
VTP Domain Name : TEST
VTP Pruning Mode : Enabled
VTP V2 Mode : Enabled
VTP Traps Generation : Disabled
MD5 digest : 0x49 0x30 0x4E 0x43 0x02 0xB2 0x36 0x7A
#########
Make a change to the VTP database and then verify that the Revision number has incremented and has updated across the transparent switch. The transparent switch will not install the update into its vlan database, only pass it along.
#########
CORE01#sh vtp status
VTP Version : running VTP2
Configuration Revision : 15
Maximum VLANs supported locally : 1005
Number of existing VLANs : 17
VTP Operating Mode : Server
VTP Domain Name : TEST
VTP Pruning Mode : Disabled
VTP V2 Mode : Enabled
VTP Traps Generation : Disabled
MD5 digest : 0x02 0x24 0xF4 0xD7 0x11 0x28 0x33 0xFC
SW02#sh vtp status
VTP Version : running VTP2
Configuration Revision : 15
Maximum VLANs supported locally : 1005
Number of existing VLANs : 17
VTP Operating Mode : Client
VTP Domain Name : TEST
VTP Pruning Mode : Disabled
VTP V2 Mode : Enabled
VTP Traps Generation : Disabled
MD5 digest : 0x02 0x24 0xF4 0xD7 0x11 0x28 0x33 0xFC
#########
Now if the transparent switch’s domain doesn’t match that of the rest of the network, updates will fail to be forwarded.
#########
CORE02#sh vtp status
VTP Version : running VTP2
Configuration Revision : 0
Maximum VLANs supported locally : 1005
Number of existing VLANs : 17
VTP Operating Mode : Transparent
VTP Domain Name : BROKEN
VTP Pruning Mode : Disabled
VTP V2 Mode : Enabled
VTP Traps Generation : Disabled
MD5 digest :0xB3 0x30 0x72 0x9D 0x83 0x74 0xCD 0xAD
#########
When a change is made it the vlan database, it will not update across the broken domain.
#########
CORE01(config)#do sh vtp status
VTP Version : running VTP2
Configuration Revision : 18
Maximum VLANs supported locally : 1005
Number of existing VLANs : 18
VTP Operating Mode : Server
VTP Domain Name : TEST
VTP Pruning Mode : Disabled
VTP V2 Mode : Enabled
VTP Traps Generation : Disabled
MD5 digest : 0xA2 0x09 0xB2 0x86 0xD8 0xC8 0xBE 0x48
SW02#sh vtp status
VTP Version : running VTP2
Configuration Revision : 15
Maximum VLANs supported locally : 1005
Number of existing VLANs : 17
VTP Operating Mode : Client
VTP Domain Name : TEST
VTP Pruning Mode : Disabled
VTP V2 Mode : Enabled
VTP Traps Generation : Disabled
MD5 digest : 0x02 0x24 0xF4 0xD7 0x11 0x28 0x33 0xFC
#########
Conclusion:
Even though the documentation has been corrected in newer version, this doesn’t mean that myth won’t continue to live on. It’s always a good idea to verify what the documentation is saying by setting up a practice lab. Or you may find that certain assumptions are incorrect.