TMOs

TMOS, short for Traffic Management Operating System, is the proprietary operating system used by F5 Networks' BIG-IP family of application delivery controllers. It runs on both hardware BIG-IP appliances and virtual editions, providing the platform’s control plane and data plane for traffic management, security, and access services. TMOS supports a modular set of software modules, including Local Traffic Manager (LTM) for load balancing, Global Traffic Manager (GTM, now BIG-IP DNS), Application Security Manager (ASM), Access Policy Manager (APM), and Advanced Firewall Manager (AFM).

The architecture emphasizes performance and reliability: a hardened Linux-based kernel with process isolation per module, high availability through active/standby failover, and centralized configuration management. Management is primarily via the Traffic Management Shell (tmsh) command-line interface, the web-based Configuration Utility, and programmatic access through the iControl API (REST in newer versions, with historical SOAP support). The iRules scripting language lets administrators define custom traffic handling within LTM.

TMOS also encompasses core networking and security capabilities delivered by its modules, including SSL offloading and termination, TCP optimization, application-layer security, web access control, and DNS services in the BIG-IP DNS module. Software upgrades, licensing, and virtualization support enable deployment in on-premises hardware, virtual environments, and cloud platforms.