The following SAP encapsulations are supported on the 7750 SR and 7950 XRS VPRN service:
Ethernet null
Ethernet dot1q
SONET/SDH IPCP
SONET/SDH ATM
ATM - LLC SNAP or VC-MUX
Cisco HDLC
QinQ
LAG
Tunnel (IPsec or GRE)
Frame Relay