The following lists encapsulation service options on Ethernet ports:
null
Supports a single service on the port. For example, where a single customer with a single service customer edge (CE) device is attached to the port. The encapsulation ID is always 0 (zero).
dot1q
Supports multiple services for one customer or services for multiple customers (Figure: Multiple SAPs on a single port). The encapsulation ID used to distinguish an individual service is the VLAN ID in the IEEE 802.1Q header. For example, the port is connected to a Ethernet switch with multiple downstream customers.
QinQ
The QinQ encapsulation type adds a IEEE 802.1Q tag to the 802.1Q tagged packets entering the network, to expand the VLAN space by tagging tagged packets, producing a double-tagged frame. The 7210 SAS-R6, and 7210 SAS-R12 support QinQ encapsulation for access ports in network mode.
The preceding figure shows multiple SAPs used for customer service delivery on the same port and belonging to the same service, along with SDP used for service transport on 7210 SAS devices that support MPLS uplinks (also known as network mode platforms). This is supported only in network mode.