tagged vs. untagged VLAN

[daniel.dib at reaper.nu (Daniel Dib)]

-----Original Message-----
From: Jay Nakamura [mailto:zeusdadog at gmail.com] 
Sent: den 29 september 2010 03:28
To: NANOG
Subject: tagged vs. untagged VLAN

>In a SP environment, you need to hand off two VLANs to a customer, is
>there any advantage or disadvantage in doing the following two setups?
>
>- One untagged and one tagged VLAN
>- Two tagged VLAN and no untagged VLAN
>
>I can't think of anything other than some equipment may not let you
>have no untagged VLAN.  But it's bugging me that something could go
>wrong by not having untagged native VLAN that I can't think of.


I would go with tagged for both VLANs. If you can't tag the native in your
equipment create a dummy VLAN and use it as native on the link and all VLANs
will be tagged. If you know the customer will be using more VLANs later on
Q-in-Q might be a good solution or you will have to transport a lot of VLANs
in your network and they might collide with other customers etc.

/Daniel