Troubles related to vlan trunking mismatch

[IngGerardo013]

Hello guys,

     Somebody knows what kind of problems can be arise when you have vlan mismatch between two switches that have configured diferent trunk native vlan between these switches , slow trafic on the network?... lost of packets?.. Thanks a lots guys

[Jon Marshall]

You can definitely get packet loss because if you are running a version of PVST+ STP will block one of the vlans on the trunk link in order to avoid a possible loop.

Basically with a different native vlan on either end you have joined two vlans together. So STP reports a PVID inconsistency and will block for one of those vlans.

Jon

[IngGerardo013]

We have a network that is experiencing slow speed on their network, this network is a start topology, and they have vlans mismatchs... there is no redundancy... switches can block ports despite there is no duble links between switches?....

[Jon Marshall]

switches can block ports despite there is no duble links between switches?....

yes because it is done a per trunk link basis. STP doesn't block the whole trunk link only the native vlan on that trunk link providing you are running a per vlan STP.

That said you would probably be seeing loss of connectivity rather than slow speed as if STP did block the vlan no packets would pass.

Jon