AAL
(ATM Adaption Layer) The part of the ATM protocol that breaks up application packets into 48-byte payloads which become ATM cells when the 5-byte headers are attached. The AAL resides between the higher layer transport protocols and the ATM layer. The AAL comprises two layers: Convergence Sublayer (CS) and Segmentation & Reassembly Sublayer (SAR). There are four types of AALs.
AAL-5 Connection-oriented, Unspecified Bit Rate (UBR). Least amount of error checking and retransmission.
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.
Note: aal5snap is the default encapsulation and the most widely used because it allows multiple protocols to be carried over one PVC.
So basically, AAL-5 is the actual ATM protocol and snap is an encapsulation that allows other protocols (such as TCP/IP and IPX) to traverse the same ATM network.
Hope this help...
~rd
