[c-nsp] What if....... Dot1q

[Terje Bless]

Voll, Scott <Scott.Voll at wesd.org> wrote:

>If I have a Metro E provider who doesn't support QinQ, but they use
>Cisco equipment and each circuit is a Dot1q Vlan, Can I tunnel Vlan tags
>across via an ISL Trunk?

Caveat Ignoramus, but AFAICT, no, this won't work. If they provide you with an
access port it will drop all VLAN tagged frames (both ISL and dot1q) and might
enter port security errdisable state depending on their config.

Trunking across this would require the provider to support QinQ (and probably
L2TP for STP, VTP, and CDP) by providing you with a “tunnell” port instead of an
“access” port; or encapsulating the trunk in something like EoMPLS before
entering the provider network.

Then again, they should have the technical capability to provide you this
service, but might of course opt to not offer that product to you. Have you
tried asking them? Don't ask for QinQ but rather that you want to run a trunk
across their network and suggest that something similar to QinQ would be good.


QinQ and L2TP are explained quite well in the chapters “Configuring IEEE 802.1Q
Tunneling”[0] and “Configuring Layer 2 Protocol Tunneling (L2PT)”[1] in the
12.2SX Configuration Guide[2].


[0] — <http://www.cisco.com/en/US/customer/products/hw/switches/
ps708/products_configuration_guide_chapter09186a0080160a90.html>

[1] — <http://www.cisco.com/en/US/customer/products/hw/switches/
ps708/products_configuration_guide_chapter09186a0080160a90.html>

[2] — <http://www.cisco.com/en/US/customer/products/hw/switches/
ps708/products_configuration_guide_book09186a00801609ea.html>

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