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Thanks. I admit its hard to ask a question, when your not sure how to ask it
I will be labbing it again in a few hours in some online rack time. These are notes from my last session and I wanted to get a good understanding before doing it again. fyi, it is actually the beginning of ipexpert’s version 10, volume 2, section 5 on l2 protocol tunneling. There will be a couple more switches involved, but this is just the beginning.
it’s a very interesting lab…just having a hard time grasping the concept.
On Wed, Aug 6, 2008 at 11:02 AM, Jonathan Greenwood II wrote:
> No I read your questions, and thats my fault. I have to lab it up to > test. > > But my thoughts on question 1: Yes the forwarding behavior would be > correct since you have the l2protocol-tunnel cdp. I haven’t used it in that > manner without the switchport mode dot1q-tunnel. > My thoughts on question 2: Yes Dest Mac will be the same. > > My thoughts on question 3: Can you post your output when you do the sh cdp > nei on CAT2 Fa0/23? I think its not showing BB1 as a neighbor on CAT2 > Fa0/23 because you are not performing dot1q-tunneling. I don’t think a > regular trunk overrides the cdp tunneling behavior but more so its not how > the technology works with that particular configuration. > > I have to lab it up myself to play with that scenario you have setup. > Sorry on my lack up reading earlier but those are my thoughts on your > question. > > R/ > > Jonathan > On Wed, Aug 6, 2008 at 11:47 AM, Hobbs wrote: > >> Jonathan, it is a question. I am not looking for a command to make it >> work. it is working. please read the entire email. If my question doesn’t >> make sense, I can try and rephrase. >> >> >> On Wed, Aug 6, 2008 at 10:42 AM, Jonathan Greenwood II > > wrote: >> >>> 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 >>> 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 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
Blogs and organic groups at http://www.ccie.net