This chapter covered the legacy management models for SONiC NOS. The configuration method and sample example using the management models such as Linux shell, Python-based SONiC CLI, FRRouting shell, config_db.json file, and SNMP were discussed. The advantage, disadvantages, and operational complexity can be inferred in using these disparate management models. To avoid these hardships, the SONiC Management Framework model pioneered by Dell Technologies provides a single way to configure features and is a model that is configured and managed from a single place.