So the last few hours I have been reading about the native VLAN on Cisco Switches and have found allot of contradicting \ misinformed opinions on the internet.
First of all Clause 9 of the 1998 802.1Q standard defines
Frames belonging to the native VLAN do NOT carry VLAN tags when sent over the trunk. Conversely, if an untagged frame is received on a trunk port, the frame is associated with the Native VLAN for this port.
I'm sure that I had read control protocol information was untagged http://www.cisco.com/en/US/products/hw/switches/ps4324/products_tech_note09186a0080094713.shtml tells me differently.
So I guess it would make sense to prune both the native vlan and Vlan 1. Since pruning (switchport trunk allowed) won't affect the control protocol information.
http://blog.ine.com/2008/07/17/pvst-explained/ also tells me when useing PVST STP the switch sends the BPDU both tagged and un tagged.
This link https://learningnetwork.cisco.com/thread/7582 also had what seemed good information.
Could you please confirm that I have read is correct?
Also does the native vlan have to exist in the VTP Domain? I think not
I think the biggest mistake I made was assuming all control information was untagged
Or from a different sourse this is what I belive
STP and DTP frames have no relation to VLAN, so are always transmited over Native VLAN unless using pvst+
http://blog.ine.com/2008/07/17/pvst-explained/
CDP/VTP/PAgP/UDLD are always transmited over VLAN 1, if Native VLAN is 1 then will be transmited in untagged form, if VLAN 1 is tagged (Native VLAN is other VLAN then 1), protocols will be tagged with 1.
http://www.cisco.com/en/US/products/hw/switches/ps4324/products_tech_note09186a0080094713.shtml
tells us that even if the VLAN is pruned the traffic for these protocols will still flow.
Thanks.
