We have deployed 2 F5-AFM modules between two Routers. One router is located at our Network, and another one is located at external network. Between 2 routers we have BGP, so we want to deploy F5-AFM Modules as Transparent (L2) mode, due to lack of ARM modules on them. Another tip is that we configure a Sync-Only group between 2 F5 modules, so they should work as Active/Active boxes by using VLAN GROUP objects for 2 vlans "Internal" and "External".
We test our traffic and everything was good, but just for the first 4 hours! After that no traffic could be sent or received!!! But after clearing the Arp cache on our router, or initiating a ping command respect to the destind IP address of the peer router, the BGP connection would be established again,and everything works, but just for 4 hours again!
It should be noted that, the port-channels which are used between our local router and F5 boxes and between F5 boxes and external router, work in "mode ON". It is due to needing all the phy. ports act as active members.