dahdi timing

Home » Asterisk Users » dahdi timing
Asterisk Users No Comments

Hi,

We heavily use meetme/SLA functionality in Asterisk, and continuously run into issues with dahdi timing. The two errors we get are:

ERROR[6518] res_timing_dahdi.c: Failed to configure DAHDI timing fd for 0 sample timer ticks

WARNING[22024] app_meetme.c: Unable to write frame to channel

Right now, dahdi in our setup uses the software timer (with res_timing_dahdi.so which gives much better results compared to res_timing_timerfd.so). On an idle system (Centos 6, Asterisk 1.8.7, dahdi 2.5), dahdi_test results are pretty good at about %99.99. However, when loaded, the numbers fluctuate between %99.90 and %99.99 which seem to cause the above errors.

We tried Sangoma UT50 as a timing device (it’s USB based), but the test results were worse (between 99.98 – 99.97 when idle, and had big dips when loaded and there is no IRQ sharing).

We are planning to order Digium AEX410 cards hoping they will be an improvement over dahdi_dummy and Sangoma. Does anyone have experience with these cards? Can we get a stable performance from them even under load?

Also (for Digium developers who might be reading this list), any plans for decoupling SLA from dahdi timing in future releases of Asterisk?

Thanks,
Mert