[c-nsp] Trunked VLANs over FTTC VDSL2

Tarko Tikan tarko at lanparty.ee
Wed Jan 13 06:02:21 EST 2016


> Anyone out there trunking multiple VLANs to a Cisco CPE over FTTC, in a
> similar position?

I'm actually testing this as we speak. Not with BT but it doesn't really 

See below for the config that should theoretically work, in reality it 
does not. The packets are correctly double tagged in LAN>VDSL direction 
but in VDSL>LAN direction packets are lost after they reach Vlan100 
interface (by looking at packet counters). This is probably because 
Vlan100 interface is not really expecting packets with dot1Q ethertype.

I haven't opened the case with Cisco yet but I don't have high hopes. 
Having dot1q-tunnel on this platform is most likely mistake.

Do you know any other devices/vendors that could theoretically do this? 
I only know about RAD ETX-2i at this point.

interface Ethernet0
  mtu 1600
  no ip address
interface Ethernet0.100
  encapsulation dot1Q 100
  bridge-group 1
interface FastEthernet0
  switchport access vlan 100
  switchport mode dot1q-tunnel
  no ip address
interface Vlan100
  mtu 1600
  no ip address
  bridge-group 1
bridge 1 protocol ieee


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