On Feb 28, 2006, at 11:59 PM, Joe Shen wrote:
why in the world would you want to do something like that rather than have another device generate flow records which you then can correlate with RADIUS accounting data?
The reason is the cost of system building. As there are a lot of broadband subscribers, if we want to corelate subscriber with web site they visit we have to make Radius allocate a fixed IP to a special subscriber. Netflow based accounting is costy and we could not guarantee its accuracy.
I would submit to you that getting such functionality built and operating via RADIUS is expensive as well. If you have a lot of broadband subscribers, your BRAS will already be busy doing what it does 'best': terminating subscriber sessions. Plus, you have to get your vendor to implement such a feature.. I haven't seen something like what you describe in the years of looking at BRAS requirements. But, that doesn't mean it doesn't exist in a scalable fashion.
In fact, we only need to identify a small set of IPs which should not be considered in accounting.
If you need to generate IP accounting for just a small set of IPs, the above engineering challenge you describe is very straightforward for capturing flow records. YMMV, of course. ;-)