Network Connectivity - How do I determine the latency of my Asterisk server?

Table of Contents

1 Problem Description
2 Answer
3 Steps

Problem Description

Suspected latency issues on your server, including:

audio quality issues (noise, distortion, etc.)
low dahdi_test scores (less than 99.80 percent)

Answer

The cyclictest is continuous test that measures the time that your processor (CPU) takes to run an specific command. The goal of this test is to confirm if the processor will respond timely over the time. It's important to mention that this test requires an extended period of time to run.

Steps

Check the latest version of the Cyclictest at http://mirror.linux.org.au/linux/kernel/people/tglx/rt-tests/

Download and compile the application:

              # wget http://www.kernel.org/pub/linux//kernel/people/clrkwllms/rt-tests/rt-tests-X.XX.tar.gz
              # tar -zxvf rt-tests-X.XX.tar.gz
              # cd rt-tests
              # make

Run the application using: chrt -f 99 ./cyclictest -t1 -p 80 -i 10000 -n -l 100000

# chrt -f 99 ./cyclictest -t1 -p 80 -i 10000 -n -l 100000
WARNING: High resolution timers not available
policy: fifo: loadavg: 1.15 1.23 1.27 2/294 28467

T: 0 (28447) P:80 I:10000 C: 847 Min: 3 Act: 7 Avg: 273 Max: 16112
(The "max" shows the highest latency detected during the execution of test)

Latency Table

~0      to    3000      Exceptional
3001   to    5000         Excellent
5001   to    8000         Good
8001   to    12000          Acceptable
12001 to    25000       Poor
25000 to    ∞              Very poor (Dahdi will disable the Sangoma Card)