Hardware diffrence

In summary:

BIG-IP is a modular software architecture. While specifically designed as a reverse proxy and load balancer, BIG-IP can perform many network and application functions. The individual modules (LTM, GTM, APM, ASM, AFM, WA/WOM/AAM) work at different layers of the stack to provide optimization, acceleration, and security of network communications. BIG-IP software and modules are essentially the same for all of the hardware versions, which basically dictate "speeds and feeds" and the number of modules that will run on the platform concurrently. Speeds and feeds include physical interface speeds and quantity, caching and compression, SSL offload, and overall L4-L7 throughput.

what I want to know is, BIG-IP product suite is part of BIG-IP hardware or they are different product ranges

So to answer your question specifically, BIG-IP software and hardware are different things. All of the software (modules) will run on all of the hardware platforms with varying degrees of combinations and performance.