From: Jonathan Greenwood II (gwood83@gmail.com)
Date: Wed Aug 06 2008 - 13:42:12 ART
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 <deadheadblues@gmail.com> 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 <gwood83@gmail.com>wrote:
>
>> You need to change the switchport mode from access to dot1q-tunnel.
>>
>> On Wed, Aug 6, 2008 at 11:27 AM, Hobbs <deadheadblues@gmail.com> 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,
>>>
>>>
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