Operation Manual – VLAN-QinQH3C S9500 Series Routing Switches Chapter 5 Q-in-Q Configuration5-8Note:Following describes how a packet is forwarded from Switch A to Switch C.z As packets sourced from VLAN 10 match rule 0 of the ACL 4000 configured onSwitch A, a packet of this type is tagged with two VLAN tags when it flow in theGigabitEthernet2/1/1 port of Switch A. The outer VLAN tag is of VLAN 11 and thenested VLAN tag is of VLAN 10.z Switch A then forwards the tagged packet to Switch B through itsGigabitEthernet2/1/2 port.z After receiving the packet through its GigabitEthernet3/1/2 port, Switch B forwardsthe packet in VLAN 11. As the GigabitEthernet3/1/1 port of Switch B, which is ofhybrid 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) whensending the packet through its GigabitEthernet3/1/1 port.z So the packet only carries one VLAN tag (VLAN tag of VLAN 10) with it whenentering the GigabitEthernet2/1/2 port of Switch C, Switch C then sends the packetto 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. VerificationThe configuration is successful if packets sourced from the networks connected toSwitch A can reach those connected to Switch C, or packets sourced from the networksconnected to Switch C can reach those connected to Switch A.5.4 Adjusting TPID Values for Q-in-Q Packets5.4.1 Configuration PrerequisitesAs VLAN-VPN uplink ports often works with the VLAN VPN ports, to enable aVLAN-VPN uplink port, make sure that VLAN VPN is not enabled on the port.
