The two valid modes for the Juniper ATP Appliance are all-in-one and core. The all-in-one mode is a single appliance that performs both the collector and the core functions. The collector function collects traffic from the network and sends it to the core function for analysis and detection. The core function performs the threat detection, mitigation, and analytics. The all-in-one mode is suitable for small to medium-sized networks that do not require high scalability or performance. The core mode is a dedicated appliance that performs only the core function. The core mode is used in conjunction with one or more collector appliances that collect traffic from the network and send it to the core appliance for analysis and detection. The core mode is suitable for large-scale networks that require high scalability and performance. References: Juniper Security, Professional (JNCIP-SEC) Reference Materials source and documents: https://www.juniper.net/documentation/en_US/junos/topics/concept/security-atp-appliance-overview.html