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Just turn off cdp on that particular port on CAT1 connecting to BB1. “no cdp enable”
On Wed, Aug 6, 2008 at 11:37 AM, Hobbs wrote:
> 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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