The Epipe service is designed to carry Ethernet frame payloads, so it can provide connectivity between any two SAPs that pass Ethernet frames. The following SAP encapsulations are supported on the 7450 ESS, 7750 SR, and 7950 XRS Epipe service:
Ethernet null
Ethernet dot1q
QinQ
SONET/SDH BCP-null for the 7450 ESS and 7750 SR
SONET/SDH BCP-dot1q for the 7450 ESS and 7750 SR
While different encapsulation types can be used, encapsulation mismatching can occur if the encapsulation behavior is not understood by connecting devices, which are unable to send and receive the expected traffic. For example, if the encapsulation type on one side of the Epipe is dot1q and the other is null, tagged traffic received on the null SAP is double-tagged when it is transmitted out of the dot1q SAP.
One pseudowire encapsulation mode, that is, SDP vc-type, is available: PWE3 N-to-1 Cell Mode Encapsulation.