BigIP F5 is the hardware platform that can be configured to provide the functionality of multiple modules like LTM, GTM, APM, ASM, AFM, AAM, PEM etc
LTM – Local Traffic Manager
GTM – Global Traffic Manager
APM – Access Policy Manager
ASM – Application Security Manager
AFM – Advanced Firewall Manager
AAM – Application Acceleration Manager
PEM – Policy Enforcement Manager
Each hardware platform unit can only handle x number of modules at any one time. This number varies based on the platform. F5 has multiple platforms like 1600, 3600 etc based on the hardware capability. This is a link for the different F5 Hardware Platform Specifications.
Most commonly used modules are LTM & GTM. LTM serves as a Load Balancer or Application Delivery Controller within a single geographic location. GTM is used to load balance DNS requests across multiple geographic regions. ASM provides WAF (Web Application Firewall) functionality. APM provides access restrictions, policies and VPN access. AAM provides optimized application delivery utilizing various functions like compression, caching and the next generation HTTP protocols.