I had a typo below. i mean When the client plugs in a switch on the
*LEFT*side, the ISP2 switch on the
*LEFT* side facing ISP1 goes into errdisable l2tpguard.

On Wed, Sep 9, 2009 at 1:02 PM, Justin Guagliata <[email protected]> wrote:

> It's actually like this.
>
> CLIENT------ISP1------ISP2------ISP2
> ------ISP3-------ISP3--------ISP1------CLIENT
>
> We OWN the ISP1 switches. When are doing QnQ for the client switches as
> well (including l2tp (CDP,STP,VTP)). When the client plugs in a switch on
> the right side, the ISP2 switch on the right side facing ISP1 goes into
> errdisable l2tpguard.
>
> I've been sniffing the packets and my conclusion is, you can only do l2tp
> once. In other words you can't nest and get cdp/stp/vtp from ISP1 to ISP1 or
> from cleint to cleint in the above diagram.
>
> What are your thoughts Joe?
>
> Thanks,
>
> Justin
>
>
>
> On Wed, Sep 9, 2009 at 12:51 PM, Joe Astorino <[email protected]>wrote:
>
>> Let me fully understand what you are saying.  I am picturing:
>>
>> Client Switch ----- ISP1-----ISP2-----ISP3-----Client Switch
>>
>> Is that right?  So you have ISP1,2, and 3 all doing Q-Q ?
>>
>>
>> On Wed, Sep 9, 2009 at 12:40 PM, Justin Guagliata <[email protected]>wrote:
>>
>>> Joe,
>>>
>>> What if you have a link that spans 3 providers, all of which are
>>> performing QnQ. Will it be possible to l2tunnel all the way across the link
>>> span. It seems like the l2tunnel can't survive multiple hops. If one
>>> provider is involved, I can span that fine, as soon as I add a second and
>>> try to use l2tunnel, the provider in the middle goes errdisable.
>>>
>>>
>>> On Wed, Sep 9, 2009 at 12:26 PM, Joe Astorino <[email protected]>wrote:
>>>
>>>> Also, check out this blog post, it may help you understand that
>>>> particular error:
>>>> http://ipexpert.ccieblog.com/2009/07/29/l2-tunneling/
>>>>
>>>>
>>>> On Wed, Sep 9, 2009 at 12:24 PM, Joe Astorino 
>>>> <[email protected]>wrote:
>>>>
>>>>> Typically you see this when a port configured for "switchport mode
>>>>> dot1q-tunnel" and "l2protocol-tunnel" is receiving an l2protocol-tunnel
>>>>> frame from another switch that it is connected to.  Make sure your 
>>>>> customer
>>>>> is not configuring l2protocol-tunnel anywhere on their end, and is simply
>>>>> trunking to you.
>>>>>
>>>>> On Wed, Sep 9, 2009 at 10:20 AM, Justin Guagliata 
>>>>> <[email protected]>wrote:
>>>>>
>>>>>> I have a link with a provider spanning two locations. The provider is
>>>>>> running QinQ and we have a trunk setup across the link. Recently we had 
>>>>>> the
>>>>>> requirement to start doing QnQ for a few "customers" so we attempted to 
>>>>>> do
>>>>>> QinQ for our downstream neighbors. The problem is, when our downstream
>>>>>> "customer" plugs in one switch, our port on the provider side goes into
>>>>>> errdisable due to l2ptguard.
>>>>>>
>>>>>> I believe if the customer plugs a switch on the other side, the link
>>>>>> will come up and be fine. The problem is, we can't afford to lose our 
>>>>>> link
>>>>>> because the customer had a switch die or is missing a switch on one side 
>>>>>> for
>>>>>> some other reason.
>>>>>>
>>>>>> The only solution i can think up is to have the provider disable
>>>>>> errdiable for the l2ptguard cause.
>>>>>>
>>>>>> Does anyone else have any ideas, suggestion?
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Justin
>>>>>>
>>>>>> _______________________________________________
>>>>>> For more information regarding industry leading CCIE Lab training,
>>>>>> please visit www.ipexpert.com
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Regards,
>>>>>
>>>>> Joe Astorino - CCIE #24347 R&S
>>>>> Technical Instructor - IPexpert, Inc.
>>>>> Cell: +1.586.212.6107
>>>>> Fax: +1.810.454.0130
>>>>> Mailto:  [email protected]
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Regards,
>>>>
>>>> Joe Astorino - CCIE #24347 R&S
>>>> Technical Instructor - IPexpert, Inc.
>>>> Cell: +1.586.212.6107
>>>> Fax: +1.810.454.0130
>>>> Mailto:  [email protected]
>>>>
>>>
>>>
>>
>>
>> --
>> Regards,
>>
>> Joe Astorino - CCIE #24347 R&S
>> Technical Instructor - IPexpert, Inc.
>> Cell: +1.586.212.6107
>> Fax: +1.810.454.0130
>> Mailto:  [email protected]
>>
>
>
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