How to directly connect two cisco ASA

[aslam.bajwa]

Hello  , 

i have two Cisco Firewall ASA 5545 and ASA 5516:

ASA 5545 is Datacenter firewall

ASA 5516 is perimeter firewall 

what is the best practice to connect both firewalls (ASA 5545 OUT===========ASA 5516 INN)

should L3 interface b/w two firewall OR trunk ?

Regards 

[Karsten Iwen]

I would always directly start with a trunk between them. That gives to to biggest flexibility.