Does F5-BIG-ASM-4200V Support LTM

You might be right, I may have taken the HA config for granted. Actually I have only LTM+ASM combos, where setting up high availability is standard practice. I will investigate a bit.

I am working with the normal Config-Sync Failover Network HA

Interesting, is the HA configuration available in the GUI of the ASM-only appliance? The ASM Implementations manual states to provision both LTM and ASM for sync-failover config, which is a bit confusing if one has only ASM licensed. Unfortunately I don't have ASM only appliance at hand to check. Could install a VE sometime next week to check, though. Haven't seen recently ASM only implementations since sw version 9 times. Only LTM+ASM or Best Bundle licenses nowadays. For getting LTM functionality, it may be more cost effective to have a separate LTM pair in front of the 4200 ASM's. The LTM add-on license fee is a bit hefty. Think a LTM 2x00s pair would suffice to feed 2 ASM 4200s, one could almost get a pair of 2000s' at the cost of single LTM add-on for the 4200 ASM if you count also support fees. Then you could use both ASMs active?