RFC1483 describes two different methods for carrying connectionless network interconnect traffic over an ATM network: routed protocol data units (PDUs) and bridged PDUs. Cisco SDM supports the configuration of RFC 1483 routing, and enables you to configure two encapsulation types: AAL5MUX, and AAL5SNAP.
AAL5MUX: AAL5 MUX encapsulation supports only a single protocol (IP or IPX) per PVC.
AAL5SNAP: AAL5 Logical Link Control/Subnetwork Access Protocol (LLC/SNAP) encapsulation supports Inverse ARP and incorporates the LLC/SNAP that precedes the protocol datagram. This allows the multiple protocols to transverse the same PVC.