SIP Stress Testing -Part 2 (SIPSAK)


This is part 2 of the “SIP Stress Testing” topic. In Part 1, I have talked about the definition of the stress, opensipsctl (command line tool) and OpenSIPS-CP (Web tool) and how they are used in testing. In this part, i will talk about SIPSAK. SIPSAK is a command line tool used by SIP administrators to test the performance and the security of the SIP servers or user agents. SIPSAK is a SIP traffic generator. It generates SIP requests and sends them to the target addressed by SIP-URI . To download SIPSAK on Fedora, simply:

 # yum install sipsak

SIPSAK runs in the following modes:

♣ Default mode: Using the OPTIONS SIP method, you can  ping a target addressed by SIP-URI.

♣ Traceroute mode (-T): This is useful for learning the request’s path. The number of SIP servers on the way to the destination is counted plus the round trip time of each request is printed out.

♣ Message mode (-M): Send a short message using MESSAGE SIP request. The content of the message will be set using the option (-B).

♣ Usrloc mode (-U): Register the user addressed by SIP-URI (Set by option -s).

♣ Randtrash mode (-R) :keeps sending randomly corrupted messages to torture a SIP server’s parser. OPTIONS requests with increasing numbers of randomly crashed characters are sent to the server.

♣ Flood Mode (-F): keeps sending requests to a SIP server at high pace. OPTIONS requests with increasing CSeq numbers are sent to the server.

Current SIPSAK is missing support for the Record-Route and Route headers and IPv6 is not supported. At the stressed SIP server’s side, you need monitoring and analyzing tool which display the state of the server as numbers and figures.


  • Ping the target “test1”: #sipsak -s In this tutorial i will ping the user test1@

Here is the messages sent by SIPSAK and captured by SIPTRACE. See the User-Agent header field in the traced SIP message (User-Agent: sipsak 0.9.6). The message is taken from OpenSIPPS-CP SIPTRACE page.

If the server allows pinging. It will relay the ping message (SIP OPTION Request) and the response from the pinged target will come back to SIPSAK through the SIP server. The response will look like:

sipsak3The User-Agent: Jitsi2.2.4603.9615Linux . The target user (test1) must be registered otherwise you will get an error response message sent from the server (in case the server is programmed to do this in its routing script). The test server in this tutorial sends “404 Not Found” SIP failure:

sipsak4The server is “OpenSIPS (1.11.2-notls (x86_64/linux))” as written in the server’s response.

If you put the option -F , SIPSAK will flood the server with SIP OPTION Requests.

# sipsak -F  -s

SIPSAK is also used to test the security of the SIP server. In the previous example, flooding the server with OPTIONS SIP Requests (a lot of ping messages) is considered attack because after a short time the SIP service will be not available and the server became unable to handle more SIP requests. The test server in this tutorial sends an error message ” 500 Internal Error” after short time of flooding.

sipsak5Pinging is a way to check that the server is awake and not down. It must be available only for administration’s purposes.

Other SIPSAK examples:

  • Trace a call: # sipsak –T –s
  • Send a message to the user “test1” :# sipsak –M –s –c –B “Message Text”
  • Register the user “test1” # sipsak –U –s

Nagios monitoring tool are good complement to SIPSAK traffic generator.

SO to test the server, generate requests and check the system’s response. If you get something you don’t like, change it and do it again (Make changes, Restart the server, Generate traffic , and Check the server’s response).

More Information


The Next Part will be about SIPp which is an emulation tool which generates SIP traffic and gives some statistics.


SIP Stress Testing -Part 1 (Opensipsctl & OpenSIPS-CP)


What is Stress Testing ?

It is the process of putting so great load on the system and measuring its response. It helps to determine the maximum operating capacity of the system. The behaviour of the system will be predictable under high/peak loads.

I will mention some tools which help you in the testing of OpenSIPS SIP server under stress.


Using SIP traffic generator , we can highly load the SIP server and read the statistics. For example under certain high load, the number of dropped packets became unacceptable or the number of SIP transactions that are in use in memory is so large.

Opensipsctl Tool

It is shell script and it is used as management and monitoring tool. It has some options to generate some statistics. This script communicates with OpenSIPS server through either FIFO pipe or unix socket (The control engine is either fifo or unixsocket). The script is present in OpenSIPS sbin directory. Its configuration file opensipsctlrc is stored in OpenSIPS etc directory. Check the name of your fifo file in the configuration file. To display the available commands, type: #./opensipsctl fifo which

Here is a list of commands available in OpenSIPS 1.11.

get_statistics, reset_statistics, uptime, version, pwd, arg, which, ps, kill, debug, cache_store, cache_fetch, cache_remove, event_subscribe, events_list, subscribers_list, list_tcp_conns, help, list_blacklists, t_uac_dlg, t_uac_cancel, t_hash, t_reply, ul_rm, ul_rm_contact, ul_dump, ul_flush, ul_add, ul_show_contact, ul_sync, dlg_list, dlg_list_ctx, dlg_end_dlg, dlg_db_sync, dlg_restore_db, profile_get_size, profile_list_dlgs, profile_get_values, list_all_profiles.

  • For example to execute the command “ps”, type: #./opensipsctl fifo ps. This command display all  processes running by OpenSIPS. The output looks like:

Process::  ID=0 PID=9739 Type=attendant
Process::  ID=1 PID=9747 Type=MI FIFO
Process::  ID=2 PID=9749 Type=SIP receiver udp:
Process::  ID=3 PID=9751 Type=SIP receiver udp:
Process::  ID=4 PID=9753 Type=SIP receiver udp:
Process::  ID=5 PID=9755 Type=SIP receiver udp:
Process::  ID=6 PID=9756 Type=time_keeper
Process::  ID=7 PID=9757 Type=timer: tm-utimer
Process::  ID=8 PID=9760 Type=TCP receiver
Process::  ID=9 PID=9762 Type=TCP receiver
Process::  ID=10 PID=9764 Type=TCP receiver
Process::  ID=11 PID=9765 Type=TCP receiver
Process::  ID=12 PID=9768 Type=TCP main

  • To get the number of simultaneous calls (=dialogs in case no presence), type: #./opensipsctl fifo get_statistics dialog. Both SIP INVITE message (Establishing a Call) and SUBSCRIBE message (subscription to presence service) creates dialog. If the SIP server provides call management + presence,  the number of active dialogs will not be equal to the number of calls. The length of the call affects the memory of the SIP server not the processing because the dialog remains in the memory till one of the end parties (caller or calle) ends the dialog by sending SIP BYE message.
  • To take information about specific command, use “help” command with the name of the command as an argument. For example if you want to take information about  the command “ps”, type: #./opensipsctl fifo help ps. The output looks like:

Help:: lists all processes used by OpenSIPS
Exported by:: core

Note: Current opensipsctl does not support NoSQL databases.

OpenSIPS Control Panel (OpenSIPS-CP)

You can also use OpenSIPS control panel (OpenSIPS-CP) to do the same things. Open the web interface. Click on “System” –> “MI Commands”. Choose a command from the command list and press “Enter”. Dont forget the parameters.

OpenSIPS-CP Statistics Monitor Page

  • There are two tables needed for statistics monitoring in OpenSIPS-CP. Do the following to download the structures of monitored_stats and monitoring_stats tables in mysql opensips database:

#cd /var/www/opensips-cp/

#mysql -Dopensips -p < config/tools/system/smonitor/tables.mysql

  • On the web interface, click on “System” –> “Statistics Monitor”. You will get the following:


For example you can get some real time statistics about transaction module (TM)  by clicking on the corresponding item in the list “Module:tm”. The “inuse_transaction” sub-item gives the number of transactions in use in memory. The transactions should be released quickly and the average value of this number should be stable (transactions created and released quickly). The number of  transactions per second defines the performance of SIP proxy.

Also you can get statistics on the number of TCP/UDP packets which waiting to be processed. By clicking on “Module:net” item, you can see “waiting_udp” and “waiting_tcp” sub-items.

  • Edit the cron_job/get_opensips_stats.php file and check the value of the variable $path_to_smonitor if it is correct according to your opensips-cp.
  • Add a cron job that collects data from the opensips:

# crontab -e

Append the following entry:

* * * * *   root   php /var/www/opensips-cp/cron_job/get_opensips_stats.php > /dev/null


The MI exported functions can be called only if the corresponded modules are loaded.  Otherwise you will get an error message (command not available). For example enabling tracing by calling sip_trace (# ./opensipsctl fifo sip_trace on) will not work if the module “” is not loaded (i.e. configured to be loaded in the configuration file). You will get this error message “500 command ‘sip_trace’ not available”.

Module Not loaded –> No Exported Functions –> Error upon calling “not exist” Function


The Next Part will be about SIPSAK command line tool which is used as a SIP traffic generator to test the performance and the security of the SIP servers or user agents.