The endpoints of an AAL5 SDU mode VLL on a 7750 SR must be ATM VCs specified by port/vpi/vci. VPI/ VCI translation is supported. The endpoint can also be a FR VC, specified by port/dlci. In this case, FRF.5 FR-ATM network interworking is performed between the ATM VC SAP or the SDP and the FR VC SAP.
In SDU mode, the mandatory PWE3 control word is supported. This allows the ATM VLL to transport OAM cells along with SDU frames, using the âTâ bit to distinguish between them, to recover the original SDU length, and to carry CLP, EFCI, and UU information.