jskfan
asked on
What problem can Native VLAN mismatch causes
Let's say I have Switch1 with native Vlan 10 and Switch 2 with native Vlan 20
As far as I know Native Vlans carry untagged traffic , means the untagged traffic will be able to make it from native vlan 10 to native vlan 20, and tagged Vlan traffic (traffic belonging to non-native Vlans) does not travel through native vlans.
I do not see scenario where Native Vlan traffic is used to go through non-native vlans and vice-versa .
Any clarifications ?
Thank you
As far as I know Native Vlans carry untagged traffic , means the untagged traffic will be able to make it from native vlan 10 to native vlan 20, and tagged Vlan traffic (traffic belonging to non-native Vlans) does not travel through native vlans.
I do not see scenario where Native Vlan traffic is used to go through non-native vlans and vice-versa .
Any clarifications ?
Thank you
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makes sense..
Thanks
Thanks
However, native VLAN's are not by switch, but port. Meaning you could have different native VLAN's for different trunk ports.
SW1 <----- Trunk -----> SW2 could use native VLAN10
SW1 <----- Trunk -----> SW3 could use native VLAN20
SW2 <----- Trunk -----> SW3 could use native VLAN30
Now I would not do this, but it is technically possible.
However lets say for a second that the trunk port could go active when you had a mis-match of native VLAN's. That could cause problems.
Lets say you have the same VLAN's on all switches and you have VLAN10 = 10.1.1.0/24 and VLAN20 = 10.2.2.0/24. When the untagged traffic on VLAN10 flows from SW1 to SW2, SW2 will put the 10.1.1.0/24 traffic on VLAN20 which does not have that same subnet. So anything in VLAN10 that flows from SW1 to SW2 will not be able to communicate with anything on VLAN10 on SW2 because SW2 will put that traffic on VLAN20 which contains a different subnet.