why VLAN's required

Hello warmachinerocks,

In my opinion absolutely yes.

You need them for every step in configuration for the network part. You can associate physical interfaces on the BIG-IP system directly with VLANs. In this way, you can associate multiple interfaces with a single VLAN, or you can associate a single interface with multiple VLANs.

In a typical config if you assign IP addresses, you can do it on VLANs and use them for communication between VS-s and Pool Members.

I hope this will help.

For more explanatory info please see the link below:

https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/tmos_management_guide_10_1/tmos_vlans.html

Regards,

Preslav