[asterisk-users] Asterisk on VM with NO DAHDI hardware

Shaun Ruffell sruffell at digium.com
Wed Sep 12 22:59:07 CDT 2012

On Wed, Sep 12, 2012 at 11:52:40PM -0400, Mark Robinson wrote:
> I know that asterisk on virtual machine require a timing source.
> What would you suggest to use for timing? We will plan to use only
> SIP and IAX2.

If you're on a newish kernel (something later than v2.6.22), can use
app_confbridge instead of app_meetme, and do not need app_page
(unless you can can join the beta / wait for Asterisk 11) you can
simply use res_timining_timerfd. This will free you from any kernel
module dependencies.

If that won't work for you, you can still use DAHDI in a virtual
machine and it will provide timing for your Asterisk process via
kernel timers. If you're using app_meetme, change DAHDI_CHUNKSIZE
from 8 (1ms) to 80 (10ms). There isn't anything to be gained from a
1ms mixing chunk if you have no need to bridge audio from one card
to another when audio is being delivered to the kernel modules in
20ms chunks. This can have a big impact on reducing the load on the

Shaun Ruffell
Digium, Inc. | Linux Kernel Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at: www.digium.com & www.asterisk.org

More information about the asterisk-users mailing list