FreeRadius Losing packets in Multi-Threads mode
aland at deployingradius.com
Wed Oct 26 12:36:55 CEST 2011
Alexandre Chapellon wrote:
> Did the very same test here, with very same results.
> I find this a little bit scary to imagine that some accounting packets
> are lost (meaning I have no "proof" the requests was answered and how.
Ah... after thinking about it some more, there is no problem.
The test is wrong.
Accounting packets have *nothing* which makes them unique, other than
the packet contents. If you're sending the same packet over and over,
it's a duplicate, and gets a duplicate response.
In single threaded mode, the server receives a packet, sends a reply,
and *deletes* all knowledge about the packet. When it receives the next
one, it gets processed as if it was a new packet.
In multi-threaded mode, the server receives a packet, hands it to a
thread, which processes it and sends a reply. Crucially, the packet
isn't deleted until later, because the server avoids thread locks.
While the packet is cached, the main thread receives a "new" packet,
which looks *exactly* the same as a packet in the cache. So... the main
thread re-sends the same reply.
If you look at the statistics from the server, you'll see the
"duplicate request" counter being very high. It SHOULD be zero for
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