Hi @tag,
Frame Relay (FR) is a Layer 2 packet-switched technology that allows devices to use virtual circuits (VCs) to communicate on wide area networks (WANs).
The Asynchronous Transfer Mode (ATM) is a cell transmission standard defined by the International Telecommunication Union - Telecommunication Standardization Sector (ITU-T). ATM organizes digital data into 53-byte cells and then transmits, multiplexes, or switches the cells. ATM transmits cells in fixed length (53 bytes), provides connection-oriented services, and simplifies the transmission process.
Please refer to the product documentation for the details.
1. FR
https://support.huawei.com/hedex/hdx.do?docid=EDOC1100007335&id=dc_cfg_fr_0071&lang=en
2. ATM
https://support.huawei.com/hedex/hdx.do?docid=EDOC1100007335&id=dc_cfg_atm_0071&lang=en