Hardware diffrence

The term "BIG-IP" is a family name. It encompassed both software and hardware components. There are BIG-IP software modules:

LTM (Local Traffic Manager)
GTM (Global Traffic Manager)
APM (Access Policy Manager)
ASM (Application Security Manager)
AFM (Advanced Firewall Manager)
etc.

And there are BIG-IP Hardware platforms:

2000, 4000, 5000, 7000, 10000, VIPRION, and the older 3900, 6900, 8900 and 11000 platforms

All of the above listed software modules will run on all of the listed hardware platforms and will function, mostly, identically. The difference is in performance and overall functionality (how many modules can be installed on a given hardware platform).

When you purchase a hardware platform, it will come with ALL of the above listed software modules installed. They will need to be licensed and provisioned to be used though.

The one wrinkle in this description is the Virtual Edition (VE). It is, essentially, the BIG-IP software suite running in a virtual environment on YOUR hardware. All of the modules are still there and must be licensed and provisioned to be used. A VE will not perform to the extent of a hardware-based platform, so it should be used in environments where high throughput is not a requirement (ie. labs, cloud environments where many VEs can be scaled out and auto-provisioned, environments where you want to control application layer functionality, etc.).