[Asterisk-Users] (Semi-OT) QoS Question FTP Living with Asterisk

[Matt Roth]

Steve Totaro wrote:

> Not sure if cheesy is the right word.  Sound solution may be a better 
> adjective.  Adding two NICs, one to each machine and connecting them 
> directly via crossover cable on a totally separate network may be my 
> best solution.  No FTP traffic would even hit the NIC or the network 
> used for VoIP and everything else.
>
> Unless there is a setting in Linux somewhere (still holding out hope)

Steve,

Part of your problem may be that you are mixing batches of leg files on 
the Asterisk server every five minutes.  Mixing the leg files is 
processor intensive and I'd be surprised if mixing them in batches 
didn't degrade your call quality.  In general, it is better to perform 
tasks such as this on a remote server.

If the problem is purely bandwidth related, the batch processing is 
probably aggravating that as well.  It is relatively simple to transfer 
the leg files as each individual call terminates.  Staggering the 
transfers of the files may provide all of the throttling you need.

I am currently administrating an Asterisk server that functions as the 
switch for an inbound call center.  On a busy day it handles over 13,000 
digital recordings in the PCM format.  This post caught my eye, because 
I use a dedicated NIC and a crossover cable to transfer them via NFS.  
 From my observations, this method adds very little load to the server 
(although I am considering NAPI and other methods to throttle the number 
of interrupts generated by the NICs).  The entire setup is documented here:

<http://lists.digium.com/pipermail/asterisk-users/2005-October/120930.html>

I've made some small alterations in our production environment since the 
writing of that post.  The most important one concerns the use of the 
"MONITOR_EXEC" variables in the dialplan to trigger the transferring of 
the leg files.  That method turned out to be unreliable.  Hijacking 
soxmix, as documented in the following post, handles this task reliably:

<http://lists.digium.com/pipermail/asterisk-users/2006-April/147202.html>

See "show application monitor" in the Asterisk CLI for details on 
getting your custom "soxmix" script invoked at the end of each call.

As I mentioned, offloading tasks such as mixing the leg files is a *very 
good idea*.  I have a set of four scripts on the digital recording 
server that take care of mixing the leg files, indexing them by date and 
time, exporting a list of recordings to our mainframe, archiving the 
recordings, and deleting old recordings to free up disk space.  I'd be 
happy to help you offload some of these tasks from your Asterisk server 
if you are interested.

I hope this was helpful

Matthew Roth
InterMedia Marketing Solutions
Software Engineer and Systems Developer