H3C S9500 Series Operation Manual page 144

Operation Manual – VLAN-QinQ
H3C S9500 Series Routing Switches
Note:
Following describes how a packet is forwarded from Switch A to Switch C.
As packets sourced from VLAN 10 match rule 0 of the ACL 4000 configured on
Switch A, a packet of this type is tagged with two VLAN tags when it flow in the
GigabitEthernet2/1/1 port of Switch A. The outer VLAN tag is of VLAN 11 and the
nested VLAN tag is of VLAN 10.
Switch A then forwards the tagged packet to Switch B through its
GigabitEthernet2/1/2 port.
After receiving the packet through its GigabitEthernet3/1/2 port, Switch B forwards
the packet in VLAN 11. As the GigabitEthernet3/1/1 port of Switch B, which is of
hybrid type, belongs to VLAN 11 and VLAN 11 is configured as untagged on the port,
switch B strip off the outer VLAN tag of the packet (the VALN tag of VLAN 11) when
sending the packet through its GigabitEthernet3/1/1 port.
So the packet only carries one VLAN tag (VLAN tag of VLAN 10) with it when
entering the GigabitEthernet2/1/2 port of Switch C, Switch C then sends the packet
to its GigabitEthernet2/1/1 port by forwarding the packet in VLAN 10.
It is the same case when forwarding a packet from Switch C to Switch A.
IV. Verification
The configuration is successful if packets sourced from the networks connected to
Switch A can reach those connected to Switch C, or packets sourced from the networks
connected to Switch C can reach those connected to Switch A.
5.4 Adjusting TPID Values for Q-in-Q Packets
5.4.1 Configuration Prerequisites
As VLAN-VPN uplink ports often works with the VLAN VPN ports, to enable a
VLAN-VPN uplink port, make sure that VLAN VPN is not enabled on the port.
5-8
Chapter 5 Q-in-Q Configuration