Hi, These are relatively simple questions but can someone conform for me please?
1. VTP is carried in vlan 1. CDP in vlan 1. Show VTP status says "lowest updater vlan ID....." Does this mean these protocols will be carried in the lowest number vlan? Why can't I configure this explicitly?
2. I remove vlan 1 from my trunks (trunk allowed command). CDP and VTP still work. Why? Best practises say dont use vlan 1 !!! Contradictions !!!!!
3. This will create a campus wide vlan 1 !!!! How to stop this and creating a potentially large broadcast storm in vlan 1 killing all bandwdith on the uplinks ??
4. I create a native vlan xxx. I need to allow vlan xxx on my trunk allowed statements? Does xxx need to be created on the switches? I find it works without being created but wondering....????
I know these are quite basic questions but when you don't do campus switched networks regularly they are important and the info on cco seems a bit fuzzy.
Yes if you remove vlan 1 from trunk cdp,ctp will go on vlan 1 and these features will still work. Now with PVST+ all vlans will run their own STP instance so your switch will be root bridge for multiple vlans but for vlan 1 STP BPDUs will not cross switches so their STP is restircted to that local switch which does not bring any danger indication to me atleast :)
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