On 19 Aug 2007, at 02:57, Hugh Irvine wrote:
On 17 Aug 2007, at 23:35, Alex Rubenstein wrote:
Seriously, can I also add that RADIUS interim accounting is almost essential in this scenario. Real world accounting and session boundaries mis-match badly making it almost mandatory to use interim accounting records to get an approximation of what the figures look like from a billing perspective. I'll also add "watch out for missing records" - I've found RADIUS to be the lossiest network protocol per foot of cabling that I've ever used.
I can't say I've seen this.
This sort of thing tends to happen in "wholesale" operations where the downstream has a congested link.
I've mostly seen it when loss of a link (voice trunks, L2TP tunnels) causes a lot of sessions to bounce at once. I possibly misspoke by saying RADIUS protocol when I probably ought to have said RADIUS subsystem. In these cases I strongly suspect a limit on buffer space at the NAS (or equivalent) end of things for keeping track of ACKs. I definitely used to see this on Max 4000s when I used to have a voice carrier who had a habit of dropping several trunks at a time losing me 100s of sessions simultaneously - it'd only be a few packets but it was enough to make the books not balance which is why it got spotted. And as the physical links involved were often in the 10s of feet region...
Having collected hundreds of millions of radius packets in my years (hell, we were running PM-2e's in 1996), and have written several accounting collectors, I can't say I agree.
If you follow the specifications properly, unless you have issues with the transmitting device (read: BUG), RADIUS accounting has always been good to me.
You can sometimes improve this situation by transporting the RADIUS requests over some form of TCP tunnel.
And, I've not seen the behavior you describe that requires interim.
DSL and/or cable systems usually have long-held connections that often cross billing boundaries - interim accounting is useful in this scenario.
Exactly.
Dialup connections are not usually long enough to warrant interim accounting.
regards
Hugh