asterisk.md

Asterisk

The only requirement is for Asterisk (or another IPBX) to log its CDR in a csv file with one record per line and the following columns:

• sip_call_id
• linked_id
• unique_id
• sequence
• caller_id_number
• caller_id
• destination_extension
• destination_context
• disposition
• hangup_cause
• start_time
• answer_time
• end_time
• duration
• billsec
• last_application
• last_application_data
• channel
• destination_channel
• packet_sent
• packet_received
• local_rx_packet_loss
• local_tx_packet_loss
• local_rx_jitter
• local_tx_jitter
• local_jitter_max
• local_jitter_min
• local_jitter_normal_deviation
• local_jitter_standard_deviation
• rtt
• minrtt
• maxrtt
• account_code

You will find the cdr config file and the helper macro in the asterisk directory.

To trigger the macro at the end of a call, just add the following operation at the beginning of a call handling:

    same => n,Set(CHANNEL(hangup_handler_push)=qos-cdr,s,1)

You can notice that RTT, jitter and packet loss are logged into each CDR. However, these values are not used to compute the MOS of each call for 2 main reasons:

• RTCP gives a better precision showing the evolution of these values during the call,
• Asterisk returned values seems not always trustworthy to me.

Nevertheless, I chose to log them anyway and keep them in elasticsearch just in case.