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Thank you for the reply, but I am not having any configuration issues. It is only a question. I don’t want CAT1 to see BB1 as a neighbor, I am just trying to understand why it doesn’t.
I am not doing dot1q tunneling
On Wed, Aug 6, 2008 at 10:32 AM, Jonathan Greenwood II wrote:
> You need to change the switchport mode from access to dot1q-tunnel. > > On Wed, Aug 6, 2008 at 11:27 AM, Hobbs wrote: > >> Hello, >> >> I am trying get my head around a semi-complex protocol tunneling task, but >> I >> have some questions on the basics. >> >> Here’s the topology >> >> “Near end host”: BB1 >> “Far end switch”: CAT2 >> >> [BB1]f0/1—–f0/11[CAT1]f0/23—–dot1q >> trunk—–f0/23[CAT2]f0/1—–f0/1[R1] >> >> To get cdp tunneling to work (and it does work) I enable this on CAT1 and >> CAT2 access ports: >> >> CAT1: >> interface f0/11 >> switchport mode access >> switchport access vlan 100 >> l2protocol-tunneling cdp >> no cdp enable >> >> CAT2: >> interface f0/1 >> switchport mode access >> switchport access vlan 100 >> l2protocol-tunneling cdp >> no cdp enable >> >> The trunk between CAT1 and CAT2 carries vlan 100 as well as others. >> >> This is what I understand so far: >> >> BB1 sends a multicast CDP packet on it’s port to CAT1. >> Since CAT1 has cdp tunneling enabled, it forwards it rather than processes >> it. Is this correct? >> CAT1 sends this packet out all trunk links that have vlan 100 allowed AND >> any access ports on VLAN100. Is this correct? >> The packet still has the cisco CDP destination MAC. Is this correct? >> The packet is dot1q tagged and sent out port fa0/23 and still has cisco >> CDP >> destination MAC address. Is this correct? >> >> Question: >> >> CAT2 doesn’t have tunneling on port fa0/23. >> Why doesn’t CAT2 now process this CDP packet and show BB1 has a CDP >> neighbor >> on fa0/23? >> Does trunking override this behavior? >> Does CAT2 treat this packet differently because it is a tagged CDP packet? >> >> Thanks, >> >> >> Blogs and organic groups at http://www.ccie.net >> >> _______________________________________________________________________ >> Subscription information may be found at: >> http://www.groupstudy.com/list/CCIELab.html
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