Hi Kim, Here's what i have in my notes (i debugged this four months ago :)): vlan 1 will still be used for control traffic (cdp, vtp, dtp) if you prune it off the trunk. STP will not work for vlan 1 if you prune vlan 1 from the trunk.
2009/8/20 Kim Pedersen <[email protected]> > Hi Ken, > > But that begs the question, when i state that native vlan should be > 250 on a certain trunk, but i dont allow that on the trunk (switchport > trunk allow vlan 200), to allow only another vlan (200), how does cdp > function? (lab shows that it still finds neighbor devices). > > Kim > > [email protected] wrote: > > Hi Kim, > > CDP along with VTP & STP was transported by vlan 1. Vlan 1 need not > > necessary be the native vlan. > > > > Kengyong > > CCIE #24979 > > > > > >> Hi All, > >> > >> I have a question regarding the native vlan in dot1q. Frames comming > >> from the vlan that is choosen as the native vlan is not tagged across > >> the trunk. I can manually set the native vlan to be, say 200. I can then > >> also say that i only want to allow vlan 250 to cross the trunk. I was > >> under the impression that stuff like CDP used the native vlan across > >> trunks, but if it is manually pruned (by not allowing it), why does it > >> still work? > >> > >> Am I wrong in that CDP does not use the native vlan? > >> > >> What I was trying to do was to follow Cisco's guidelines as to not use > >> the native vlan 1. However, since VTP cant prune vlan 1, I was doing it > >> manually and came up with this thought... > >> > >> Hopefully someone can clear it up for me. > >> > >> Thanks > >> > >> Sincerely, > >> Kim Pedersen > >> > >> -- > >> > >> // Freedom Matters > >> // Follow my progress on: http://kpjungle.wordpress.com > >> > >> _______________________________________________ > >> For more information regarding industry leading CCIE Lab training, > please > >> visit www.ipexpert.com > >> > >> > > > > > > -- > > // Freedom Matters > // Follow my progress on: http://kpjungle.wordpress.com > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > -- Wouter Prins [email protected] 0x301FA912
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