10-25-2009 08:10 PM - edited 03-06-2019 08:17 AM
hi Experts,
I have some queries about native vlan mismatch
1. If i am not wrong , swich bpdu , cdp , PAgp and dtp are carried over native vlan , if native vlan from both switch is different then how it works.
2. if we prune native vlan from trunk by removeing native vlan from trunk allowded vlan list then how still will be swich sent and received native vlan .(reference to bcmsn certification guide)
Thanks in advance.
10-25-2009 08:46 PM
These Protocols use Vlan 1. And Vlan 1 cannot be pruned or disabled.
Even if you Prune Vlan 1 still they will use Vlan 1.
Try to Lab it up and see the results
Zeeshan
10-25-2009 09:59 PM
Just some additional info on top of Zeeshan's. The below doc is the best practice for CatOS but the control plane protocol is the same for IOS. Please see the summary section under VLAN 1 for more info.
For your 2nd question, native vlan is really means when the switch is receiving untagged user traffic, it will use the native VLAN to forward it.
HTH,
jerry
10-25-2009 09:43 PM
Agreed with Zeeshan on this. It uses Vlan 1 to send and receive control traffic.
Removing vlan 1 from the trunk is called as Vlan 1 minimization. With this feature enabled, no user traffic is sent or received on the trunk. The switch CPU continues to send and receive control protocol frames.
regards,
-amit sing
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