SMC Networks TigerAccess SMC7816M - Manual (Page 355)

C
ONFIGURING
IEEE 802.1Q T
UNNELING
13-25
be added to this SPVLAN. The uplink port can be added to multiple
SPVLANs to carry inbound traffic for different customers onto the
service provider’s network.
When a double-tagged packet enters another trunk port in an intermediate
or core switch in the service provider’s network, the outer tag is stripped
for packet processing. When the packet exits another trunk port on the
same core switch, the same SPVLAN tag is again added to the packet.
When a packet enters the trunk port on the service provider’s egress
switch, the outer tag is again stripped for packet processing. However, the
SPVLAN tag is not added when it is sent out the tunnel port on the edge
switch into the customer’s network. The packet is sent as a normal IEEE
802.1Q-tagged frame, preserving the original VLAN numbers used in the
customer’s network.
Layer 2 Flow for Packets Coming into a Tunnel Port
A QinQ tunnel port may receive either tagged or untagged packets. No
matter how many tags the incoming packet has, it is treated as tagged
packet.