[e-nsp] Help with VMANs...

[Simon Lockhart]

All,

I'm struggling a bit to understand VMANs on Extreme, and how to achieve what
I'm trying to do.

Firstly, a quick network diagram...


   +----------+                        +----------+
   |  sw1     |                        |  sw2     |
   +-----+----+                        +-----+----+
         | Vlan 5,100 tagged                 | Vlan 5,200 tagged
         |                                   |
         +--------------+  +-----------------+
                        |  |
                       =======
                       Carrier
                        MPLS
                       Network
                       =======
                          |
                    +-----+-----+
                    |   sw3     |
                    +-----------+

So, sw1 and sw2 (X460's) are in remote PoPs. On the uplink port from sw1,
vlans 5 and 100 are tagged. On the uplink port from sw2, vlans 5 and 200 are
tagged.

Our carrier hands over both uplinks on an NNI into sw3, but adds another vlan
tag - 500 for sw1, and 501 for sw2. (so vlan 100 from sw1 appears on sw2 as
SVID 500, CVID 100).

I want sw3 to see vlans 5, 100, 200. It seemed like I could create a VMAN with
tag 500, and add the NNI port with the vman tagged. However, sw3 doesn't seem
to see traffic on vlans 5 or 100. Vlan5 would be our 'management' vlan, so
has an ipaddress configured on each switch, all in the same subnet.

Can I do this with VMANs? Does a VMAN only work if you egress the traffic on 
an untagged port out of sw3 - i.e. sw3 just strips the SVID, so another switch
downstream of sw3 could see vlan 5, 100, etc?

Many thanks,

Simon