[c-nsp] QinQ on 3550 not working?

Anton Kapela tkapela at gmail.com
Sun Jan 23 10:06:30 EST 2011


On Thu, Jan 20, 2011 at 8:00 PM, Tony <td_miles at yahoo.com> wrote:
]
>> When the Customer site switch is a 3560, I can "ping
>> 172.30.1.1" and
>> "ping vrf network2 172.40.1.1" without problem.
>>
>> When the Customer site switch is a 3550, I can "ping
>> 172.30.1.1" fine, but
>> trying to "ping vrf network2 172.40.1.1" results in no
>> replies.

I've encountered the same behavior on 3550's which are self-looped.
This method will not work properly on 3550.

>> On the 3550, the MAC address-table gets populated fine,
>> occasionally I see
>> an ARP entry for 172.40.1.1, but can't ping.
>>
>> Any suggestions on what's going wrong?

As best we could tell, tcam programming for punting ARP was up-staging
vlan and qinq tag matching. It simply cannot work on a single 3550.

>> Is there a better way to acheieve what I'm trying to do?
>
> I'm not sure if you can achieve what you're wanting to on a 3550. We've always had to use 2x 3550 to break out a QinQ service (with crossover cable/s between them), instead of using one and looping it back onto itself.

+1 to this -- I have resorted to same, and it works quite well.
Lastly, one could always terminate QinQ subints on a more
feature-dense or router-like device (eg. isr, 7200, 6500 with
flexwan/osm/etc).

-Tk


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