Forum Discussion
Why not use one internal subnet for point to point connection from your ISP router to your BigIPs? I.e. Network 192.168.0.0/24 can operate in place of 118.201.75.220/30 and you will not miss out on anything, unless you have a valid reason to maintain full BGP routing table in that BigIP cluster. Basically your ISP is wasting 3 usable public IP addresses to allocate you one useful address. You could potentially cut your ISP costs if you asked for a single routed IP solution instead of current proposal.
If you want to go with what is on the network diagram - you do need a local-only SelfIP on each unit. It's a pre-requisite to configure Floating SelfIP. BUT there's no significance for device operation if you populate these local-only SelfIPs with IP addresses that your ISP will not route in the Internet for you. So you can populate your BigIP 01 local-only SelfIP with 118.201.75.217/29 and BigIP 02 local-only SelfIP with 118.201.75.218/29. Confirm this wish with your ISP.
Since you didn't confirm the need for full BGP table, my first recommendation is still to scrap that /30 network and build something that is nice to look at.
I'm not entirely sure on the implications of using network address .220/30 or broadcast address .223/30 as host addresses without seeing full interface configuration in that ISP router (or router cluster?). In some cases it is possible to violate network sub-netting standards and get away with it. Nowadays even /31 point to point links are used in production with a bit of trickery. However, there are a strict set of criteria for this to work. Inform your ISP about your addressing plans, and then test this. 10 Minute maintenance or downtime window should suffice here.