The header error control field is a check character for the other four header bytes. Cells with corrupted headers are discarded. Using LAN emulation enables NDIS and ODI devices to access each other and native ATM devices. As long as users utilize the same service class, communication between them will be possible even if they each use different interfaces. Specific SSCSs and CSs need to be standardized for each interface.
Frame relay is the farthest along so far.
ATM 20-byte addresses are used. Low-level addresses are determined by which port on the ATM switch you are connected to. To support ATM, a router uses the selected ATM adaptation layer to add the appropriate convergence header to the variable-length packet or frame of data. The convergence sublayer then adds a CRC to the end of the end of the message and adds pad characters so that the message is an integral multiple of 48 bytes. This message could now be sent on a DXI interface.