Hello colleagues,

I am starting an ISP. And need several principle advices how to arrange my network.
The problem of RADIUS accounting is it's non real-time working mode. And if I need to arrange real-time accounting and detailed reports, am I to use NetFlow? That means, that users authorize via RADIUS but their Internet traffic is still calculated by using NetFlow. I have Cisco 2651XM as a core router and NAT, and UTM billing engine with it's RADIUS server. As I see UTM supports RADIUS authorization among with NetFlow accounting.

But is there any other rational solution?

From my personal experience I'd say that NetFlow is only preferred for either troubleshooting or if you need to account your customer's traffic in protocol- or IP address specific ways (for example if you'd like to sell a gigabyte of transit traffic more expensive than a gigabyte of traffic that stays within your own AS). If all you really need is counting bytes I'd go with radius accounting (use interim accounting updates if you need it to be "real-time") or per-interface SNMP counters (ifInOctets and ifOutOctets).

--Tom