F5 VM Sizing

The difficultly you have is it depends.

L7 traffic means you are doing some level of inspection, be that header inspection to TLS encrypt and maybe decrypt. L4 just means you are bring traffic in and passing it on with a much lower inspection level.

You also have to consider throughput or bandwidth, so this could be 5 connections but each one is pulling 10Mb each or 10000 connections running at 10k each. All of these use the resources of the big-ip and the hardware or virtual hardware its sitting on.

The more you do with it the harder you will push it, and there will come a time when you hit a limit.

Some of these might be like latency, so how long the big-ip takes to process the traffic some times this can be boosted by boosting the ve's resources up to a point. So more RAM or CPU or maybe making sure its on a fast ssd for example.

Other things like connections and bandwidth come over time and over usage. So sizing is a bit difficult.

Have you got running services already you can compare to get a benchmark?

If not i'd suggest looking at the ranges like 25Mb, 200Mb and 1Gb normally there is a pretty good costing model around these and go in low and fully explain a growth / upgrade path for if and when you get there.

Hope that sort of helps.