Call Packet Tracking (fs_cli)
By Ignat Kononov on 2021-05-25
Contents
Case one: A calls B, B answers, B hangs up.
Case two: A calls B, B decline
Case three: A calls B, B doesn't answer
Case four: A calls non-existent number
Case five: A calls wrong- form number
Case six: A calls, B answers, hang up from ASTPP GUI (Switch => Live calls)
Prerequisites
CentOs 7 server with ASTPP.
In order to install ASTPP, this document must be followed from the beginning till the end: https://docs.switzernet.com/3/public/210311-astpp-instalation/
Call Packet Tracking (fs_cli)
Case one: A calls B, B answers, B hangs up.
In this example, two accounts are assigned: A (sofia/default/8620826254@) and B (sofia/default/7843973936@)
Freeswitch allocates a channel for the upcoming session for 8620826254 (A number):
Freeswitch gets an invite twice. About double INVITE case: https://docs.switzernet.com/3/public/210526-call-packet-tracking-sip/#_Toc73032903
Freeswitch sends SDP message (further in the document will not focus on SDP messages):
What is SDP: https://www.3cx.com/pbx/sdp/, https://en.wikipedia.org/wiki/Session_Description_Protocol
Freeswitch performs audio codecs for A (27-43 strings in the log)):
Requests ASTPP for data from the mysql database (58- 88 strings in the log):
More about mysql database usage by ASTPP: https://docs.switzernet.com/3/public/210527-mysql-database-usage-by-astpp/
Call detected as local:
Сreates XML document and with the call process necessary information (90-128 strings in the log):
Freeswitch performs the routing process for A (51-55 strings in the log) and puts the call for A in the RINGING state:
Diaplan now executes instructions from an XML document (129-158 strings in the log):
What is diaplan: https://freeswitch.org/confluence/display/FREESWITCH/Dialplan
Mod_dptools now also executes instructions from an XML document (165-202 strings in the log):
What is mod_dptools: https://freeswitch.org/confluence/display/FREESWITCH/Dialplan
Freeswitch sets proxy route for sofia/default/7843973936@192.168.1.102: 40143 (B account) and sending invite:
Freeswitch performs the routing process for sofia/default/7843973936@192.168.1.102:40143 (B account number) (231- 244 strings in the logs) and enters the [calling] [processing] [ringing] state one by one for B side, since everything is fine with the data and it is ready to continue working:
A waits for B to pick up the phone:
B pick up the phone:
Freeswitch performs audio codecs (51-55 strings in the log) and change callstate to ACTIVE for B:
Freeswitch informs A that B has picked up the phone and change callstate to ACTIVE for A:
A and B exchange audio (294-308 strings in the log) and B hangs up:
Freeswitch performs HANGUP hangup procedure and change callstate to HANGUP for B (304-324 strings in the log).
Freeswitch informs A that the connection has been interrupted, start HANGUP procedure and change callstate to HANGUP for A (323-338 strings in the log):
Freeswitch changes state to DESTROY and begins closing session (342-364 strings in the log):
Session ends:
Full text log of the session: 2.txt
Case two: A calls B, B decline
Full text log of the session: 3.txt
The procedures are the same as in case one, after callstate becomes RINGING for A and B, B terminated session:
Session ends by CALL_REJECTED procedure.
Case three: A calls B, B doesn't answer
Full text log of the session: 4.txt
The procedures are the same as in case one, but after 1m In the RINGING state Freeswitch ends session with USER_BUSY error. The session ends after playing A voice auto answer.
Case four: A calls non-existent number
Full text log of the session: 5.txt
A calls 688444 (number non-existent in DB)
The procedures are the same as in case one, but an incorrect request to the database occurs, in the generated XML document, the ORIGNATION_RATE_NOT_FOUND line is entered into the two last fields:
When instructions from XML are executed by Dialplan, an "origination rates not found" error occurs.
Then the session goes through a quick termination procedure due to this error.
CS_EXECUTE used for this case and call information is entered into the database, unlike case five.
Case five: A calls wrong- form number
Full text log of the session: 6.txt
A calls !@#$%^&*()qwerty (invalid number with special characters)
The procedures are the same as in case one, but an incorrect request to the database occurs, in the generated XML document, the ORIGNATION_RATE_NOT_FOUND line is entered into the two last fields:
When instructions from XML are executed by Dialplan, an "origination rates not found" error occurs.
Then the session goes through a quick termination procedure due to this error.
CS_EXECUTE is not used for this case and call information is not entered into the database, unlike case four.
Case six: A calls, B answers, hang up from ASTPP GUI (Switch => Live calls)
The procedures are the same as in case one.
Based on the logs, when the HANGUP button is pressed in the ASTPP GUI, a simulation of the termination of the call by user B occurs.
Otherwise, everything is the same as in case one.
Full text log of the session: 7.txt
References
If a method is not described in sufficient detail in this document, you can find all the additional information about API and more in the official Freeswitch documentation: https://freeswitch.com/
End of document
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