Hi, Okay, to follow up on this. What i can wireshark myself to, it seems that Spanning-tree runs directly on top of the vlan itself, while VTP,DTP,CDP,PAGP and so on uses the LLC sublayer. I remember reading something about CDP being supported on everything able to have a SNAP header.... Anyways, my conclusion is the same as yours. Those services are not dependent on any vlan information at all. They will propagate no matter what (unless you stop them as Rick said by no cdp enable (interface)). I hope someone else can concur with this to have this one nailed to the wall :)
Sincerely, Kim Pedersen Wouter Prins wrote: > 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] <mailto:[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] <mailto:[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 <http://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 <http://www.ipexpert.com> > > > > > -- > Wouter Prins > [email protected] <mailto:[email protected]> > 0x301FA912 > -- // Freedom Matters // Follow my progress on: http://kpjungle.wordpress.com _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
