Re: L2protocol-Tunneling Sanity Check

Unbelievable.

Write erase
del flash:vlan.dat
reload
reconfigure everything

MAGIC!

On Fri, Dec 9, 2011 at 9:38 AM, Joe Astorino <joeastorino1982_at_gmail.com>wrote:

> Hey Paul!
>
> Thanks for taking the time to replicate the topology. I guess I am
> currently at a loss because my 3550 is also running the exact same code as
> yours. Here is my very specific setup. My 3560 is running a different
> version but at least that one shows it encapsulating CDP frames in the
> output of "sh l2protocol-tunnel". The 3550 does not, even after a reload.
>
> R1 Fa0/0 --> Cat1 Fa0/1
> Cat1 Fa0/24 --> Cat2 Fa0/24
> Cat2 Fa0/2 --> R2 Fa0/1
>
> Configurations:
> ----------------------
>
> Cat1 Fa0/1 & Cat2 Fa0/2
> ------------------------------------
>
> switchport mode access
> no cdp enable
> l2protocol-tunnel cdp
>
> Cat1 & Cat2 Fa0/24
> -----------------------------
>
> switchport mode access
>
>
>
>
>
> On Thu, Dec 8, 2011 at 8:13 PM, Paul Cocker <paul.cocker_at_gmx.com> wrote:
>
>> Joe,
>>
>> Seems to work for me as you expected it to ... I've included the images
>> so you can compare. Same setup as you described (no l2protocol tunnel
>> command on the inter-switch link).
>>
>> Paul
>>
>> Rack1SW1#sh ver | inc flash:
>> System image file is "flash:c3560-advipservicesk9-**mz.122-46.SE.bin"
>> Rack1SW1#sh l2protocol-tunnel | inc cdp
>> Fa0/1 cdp ---- ---- 6
>> 6 0
>> Rack1SW1#
>>
>> Rack1SW3#sh ver | inc flash:
>> System image file is "flash:/c3550-ipservicesk9-mz.**122-44.SE6.bin"
>> Rack1SW3#sh l2protocol-tunnel | inc cdp
>> Fa0/5 cdp ---- ---- 6 6
>> 0
>> Rack1SW3#
>>
>> Rack1R1#sh cdp nei
>> Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
>> S - Switch, H - Host, I - IGMP, r - Repeater
>>
>> Device ID Local Intrfce Holdtme Capability Platform Port
>> ID
>> Rack1R5 Fas 0/0 126 R S I 1841 Fas
>> 0/1
>>
>> Rack1R5#sh cdp nei
>> Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
>> S - Switch, H - Host, I - IGMP, r - Repeater
>>
>> Device ID Local Intrfce Holdtme Capability Platform Port
>> ID
>> Rack1R1 Fas 0/1 159 R S I 3725 Fas
>> 0/0
>>
>>
>>
>>
>>
>>
>>
>>
>> On 09/12/2011 00:43, Joe Astorino wrote:
>>
>>> Hey everybody, I could use some assistance validating my sanity in this
>>> situation. First, the topology
>>>
>>> R1 --- Cat1---Cat2---R2
>>>
>>> I am attempting to configure l2protocol-tunneling alone (without Q-Q at
>>> all) such that R1 and R2 see each other as directly connected in CDP. I
>>> thought for sure I had this configuration correct, but it wouldn't work.
>>> Cat1 is a 3560 and Cat2 is a 3550. I am noticing behavior on the 3550
>>> that
>>> is not happening on the 3560. Note there are no trunks and every port is
>>> an
>>> access port in VLAN 1.
>>>
>>> My original thought was this: configure "no cdp enable" and
>>> "l2protocol-tunnel cdp" on ONLY the edge ports of Cat1 and Cat2 that
>>> connect to the routers. When I do this I see Cat1 encapsulating frames
>>> in
>>> "show l2protocol-tunnel" but Cat2 never shows any decapsulated or
>>> encapsulated frames. When R1 sends a CDP frame, Cat1 should intercept it
>>> due to the l2protocol-tunnel CDP command, and rewrite the destination MAC
>>> to the proprietary Cisco MAC used for l2protocol-tunneling. That frame
>>> should then be sent out the cross switch link to Cat2. Cat2 should see
>>> that it also has "l2protocol-tunnel cdp" configured on the edge port
>>> facing
>>> R2 and rewrite the destination MAC back to the CDP multicast address and
>>> forward to R2. The same should happen the other way.
>>>
>>> Again, the 3560 shows frames encapsulated but the 3550 does not yet they
>>> have an identical configuration. First this led me to believe maybe an
>>> IOS
>>> bug in the 3550 12.2(44SE6) so I tried another version with the same
>>> results. Every example I can find out there usually only does l2pt on a
>>> single switch or if spanning multiple switches they are combining with
>>> Q-Q. I understand those concepts fine, but I am not looking to do Q-Q in
>>> this example. I don't have another 3560 on hand to test with.
>>>
>>> I started second guessing myself and thinking I needed "l2protocol-tunnel
>>> cdp" on the edge ports AND the cross switch links on both ends. When I
>>> do
>>> that, it actually works but I don't think it works for the right reasons.
>>> Ultimately, in this type of setup can anybody confirm weather you need
>>> "l2protocol-tunnel" on ALL ports between the source and destination or
>>> just
>>> on the edge ports.
>>>
>>>
>>>
>>>
>>>
>>
>
>
> --
> Regards,
>
> Joe Astorino
> CCIE #24347
> Blog: http://astorinonetworks.com
>
> "He not busy being born is busy dying" - Dylan
>
>

-- 
Regards,
Joe Astorino
CCIE #24347
Blog: http://astorinonetworks.com
"He not busy being born is busy dying" - Dylan
Blogs and organic groups at http://www.ccie.net