This section applies to all 7210 SAS platforms as described in this document, except those operating in access-uplink mode.
The 7210 SAS platforms operating in access-uplink mode can process and forward packets with more than two tags. See Configuration notes for restrictions on the use of SAPs by platforms operating in access-uplink mode.
To forward packets with two or more tags using a QinQ SAP, an Epipe service type is available for use when 7210 SAS devices are operating in network mode. This service allows for configuration of a QinQ SAP as one endpoint and the following service entities as the other endpoint:
MPLS spoke-SDP with vc-type set to vlan
The vc-vlan-tag must match the inner-tag VLAN ID value specified in the QinQ SAP.
dot1q SAP
The VLAN value configured for the dot1q SAP must match the inner-tag VLAN ID value of the QinQ SAP.
QinQ SAP
The inner VLAN tag of both QinQ SAPs configured in the service must be the same.
In the forward direction, the device will process the packet as follows:
If the packet is received on a QinQ SAP, assign an incoming packet to this service based on matching the outermost two tags in the packet header (that is, the first two tags in the packet header). It will strip only the outermost tag (single tag) on ingress and forward the rest to the other endpoint in the service.
If the other endpoint the packet is sent out of is an MPLS SDP, MPLS encapsulation is added.
If the other endpoint that the packet is sent out of is a dot1q SAP, the packet is forwarded as is, without any egress VLAN checks. It is expected that the operator will ensure that the inner tag of the packet matches the dot1q VLAN value.
If the other endpoint that the packet is sent out of is another QinQ SAP (for example, Q1.Q2 SAP), another tag (that is, Q2 tag) is added to the packet and sent out of the QinQ SAP.
In the reverse direction, the device will process the packet as follows:
If the packet is received on an MPLS SDP, the vc-vlan tag is retained as is and the VLAN tag corresponding to the outermost tag configured for the QinQ SAP (that is, the other endpoint) is added to the packet. The system does not match the vc-vlan tag received in the packet with the configured value (that is, the inner tag of the QinQ SAP). It is expected that the operator will configure both end of the service appropriately to ensure that only appropriate packets enter the service.
If the packet is received on a dot1q SAP, the outermost tag is not stripped and the VLAN tag corresponding to the outermost tag configured for the QinQ SAP is added to the packet.
If the packet is received on a QinQ SAP, assign an incoming packet to this service based on matching the outermost two tags in the packet header (that is, the first two tags in the packet header). It will strip only the outermost tag (single tag) on ingress. The VLAN tag corresponding to the outermost tag configured for the QinQ SAP (that is, the other endpoint) is added to the packet, which is forwarded from the QinQ SAP.
Therefore, the device processes packets received with two or more tags using the MPLS SDP or a dot1q SAP while classifying on the QinQ SAP ingress using two tags.