You are totally right. You know, the threat detection information will be reflected on the firewall dashboard. But for accounting information, you can use Netflow to create reports and so on based on the Netflow collector that you use. I have used PRTG and it shows the ports, percentage used and the amount of bit/bytes used.
The Threat detection will give you information about the top ten sources/destinations and protocols being used. It is great for troubleshooting, but it can be CPU intesive.
Having the ASA to send this information to a netflow collector I think it is a good approach, also, helps you out to not log certain information (To a syslog server) hence being friendly with your CPU usage
This link shows how to configure it and also you can see a little chart with the bandwith usage there
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...