notifying another server on accounting

[Michael Fowler]

Greetings,

We have a bit of an odd setup (apparently).  We have a vendor that is
providing services based on whether a user has an active and authorized
session.  In order to support this we forward on accounting data with a
detail file writer and reader, using the copy-acct-to-home-server as a
template.

This is using FreeRadius 2.1.8.

I have always felt lame ascii drawings help, so this is the setup (in
essence):

    request:  NAS -> accounting-server | copy | -> vendor
    response: NAS <- accounting-server          <- vendor

Unfortunately, we seem to be hitting a wall in terms of packets
transmitted to the vendor.  It is my understanding that the detail
reader is serial in nature, meaning it only sends one packet to the
vendor (in this case), and will not send another until it gets a
response.  The vendor is over a slow link, or the packets are otherwise
delayed, so we are getting a backlog of detail entries.  The detail
file is filling faster than it can be flushed to the vendor.

My question is, how can we fix this?

A few ideas have been batted around.  One is to write some code (via
rlm_perl or rlm_python) that essentially does what the entire
writer/reader combination is doing, only in parallel.  Meaning, it
handles transmitting and retransmitting to the vendor.  In the short
term this might be viable, but it's reinventing wheels, and it's hard to
justify long-term given most of the people dealing with this are not
programmers.

Another was to somehow load-balance the readers.  I cannot find a
configuration example to support this, but would it be possible, and
more importantly useful, to have multiple readers pointing to the same
detail file?

Any help or suggestions would be appreciated.  Thanks.

--
Michael Fowler
www.shoebox.net