It is a widely-held opinion that ATM’s acceptance and success in the private network will depend in part on its ability to interwork with existing LAN protocols and networks. There is much research and development work being done in this area, and several technologies of increasing complexity are being developed to make ATM/LAN interworking a reality. In this application note, two of the key technologies for integrating local area network data into ATM networks will be discussed. These technologies are currently under development or are being deployed in initial implementations. Consequently, several interoperability issues have been discovered. These issues, and techniques for testing implementations, will also be discussed.