Docker, FreeSwitch, sipp, sippy_cup

Sippy_cup – FreeSwitch Load Test Simplified

Ever since the entry of Docker, everyone is busy porting their applications to Docker Containers. Now with the tools like Mesos, CoreOS etc we can easily achieve scalability also. @Plivo we always dedicate ourselves to play around such new technologies. In my previous blog posts, i’ve explained how to containerize the Freeswitch, how to perform some basic load test using simple dialplans etc. My previous load tests required a bunch of basic Freeswitch servers to originate calls to flood the calls to the FreeSwitch container. So this time i’m going to use a simple method, which everyone can use even from their laptops.

Enter SIPp. SIPp is a free Open Source test tool / traffic generator for the SIP protocol. But the main issue for beginer like me is in generating a proper XML for SIPp that can match to my exact production scenarios. After googling, i came across a super simple ruby wrapper over SIPp called sippy_cup. SIPpy_cup is a simple ruby wrapper over SIPp. We just need to create a simple yaml file and sippy_cup parses this yml file and generates the XML equivalent which will be then used to generate calls. sippy_cup can also be used to generate only the XML file for SIPp.

Setting up sippy_cup is very simple. There are only two dependencies

      1) ruby (2.1.2 recomended)
      2) SIPp

Another important dependency is our local internet bandwidth. Flooding too many calls will definitely result in network bottlenecks, which i faced when i generated 1k calls from my laptop. Now let’s install SIPp.

sudo apt-get install pcaputils libpcap-dev libncurses5-dev

wget ''

tar zxvf sipp.svn.tar.gz

# compile sipp

# compile sipp with pcapplay support
make pcapplay

Once we have installed SIPp and ruby, we can install sippy_cup via ruby gems.

gem install sippy_cup

Configuring sippy_cup

First we need to create yml file for our call flow. There is a good documentation available on the Readme on various options that can be used to create the yml to suit to our call flow. My call flow is pretty simple, i’ve a DialPlan in my Docker FS, which will play an mp3 file. So below is a simple yml config for this call flow

source: <local_machine_ip>
destination: <docker_fs_ip>:<fs_port>
max_concurrent: <no_of_concurrent_calls>
calls_per_second: <calls_per_second>
number_of_calls: <total_no_of_calls>
to_user: <to_number>            # => should match the FS Dialplan
steps:                      # call flow steps
  - invite                  # Initial Call INVITE
  - wait_for_answer         # Waiting for Answer, handles 100, 180/183 and finally 200 OK
  - ack_answer              # ACK for the 200 OK
  - sleep 1000              # Sleeps for 1000 seconds
  - send_bye                # Sends BYE signal to FS

Now let’s run sippy_cup using our config yml

sippy_cup -r test.yml

Below is the output of a sample load test. Total 20 calls with 10 concurrent calls

         INVITE ---------->      20        1         0
         100 <----------         20        0         0         0
         180 <----------         0         0         0         0
         183 <----------         0         0         0         0
         200 <----------  E-RTD1 20        0         0         0
         ACK ---------->         20        0
              [ NOP ]
         Pause [    30.0s]       20                            0
         BYE ---------->         20        0
------------------------------ Test Terminated --------------------------------

----------------------------- Statistics Screen ------- [1-9]: Change Screen --
  Start Time             | 2014-10-22   19:12:40.494470 1414030360.494470
  Last Reset Time        | 2014-10-22   19:13:45.355358 1414030425.355358
  Current Time           | 2014-10-22   19:13:45.355609 1414030425.355609
  Counter Name           | Periodic value            | Cumulative value
  Elapsed Time           | 00:00:00:000000           | 00:01:04:861000
  Call Rate              |    0.000 cps              |    0.308 cps
  Incoming call created  |        0                  |        0
  OutGoing call created  |        0                  |       20
  Total Call created     |                           |       20
  Current Call           |        0                  |
  Successful call        |        0                  |       20
  Failed call            |        0                  |        0
  Response Time 1        | 00:00:00:000000           | 00:00:01:252000
  Call Length            | 00:00:00:000000           | 00:00:31:255000
------------------------------ Test Terminated --------------------------------

I, [2014-10-22T19:13:45.357508 #17234]  INFO -- : Test completed successfully!

I tried to perform a large scale load test by making 1k calls with 250 concurrent calls. My local internet was flooding with network traffic as there was real Media packets coming from the servers, though it bottlenecked my internet, but still i was able to make 994 successfull calls. I suggest to do such heavy load test on machines wich has good network throughput. Below are the output for this test.

------------------------------ Scenario Screen -------- [1-9]: Change Screen --
  Call-rate(length)   Port   Total-time  Total-calls  Remote-host
   5.0(0 ms)/1.000s   8836     585.61 s         1000

  Call limit reached (-m 1000), 0.507 s period  1 ms scheduler resolution
  6 calls (limit 250)                    Peak was 176 calls, after 150 s
  0 Running, 8 Paused, 1 Woken up
  604 dead call msg (discarded)          0 out-of-call msg (discarded)
  3 open sockets
  1490603 Total RTP pckts sent           0.000 last period RTP rate (kB/s)

                                 Messages  Retrans   Timeout   Unexpected-Msg
         INVITE ---------->      1000      332       0
         100 <----------         954       53        0         0
         180 <----------         0         0         0         0
         183 <----------         0         0         0         0
         200 <------2014-10-22  19:19:23.202714 1414030763.202714: Dead call 990-17510@ (successful), 

received 'SIP/2.0 200 OK
Via: SIP/2.0/UDP;received=;branch=z9hG4bK-17510-990-8
From: "sipp" <sip:sipp@>;tag=990
To: <sip:14158872327@>;tag=9p6t351mvXZXg
Call-ID: 990-17510@
CSeq: 2 BYE
User-Agent: Plivo
Supported: timer, precondition, path, replaces
Conte----  E-RTD1        994       126       0         0
         ACK ---------->         994       126
              [ NOP ]
       Pause [    30.0s]         994                           0
         BYE ---------->         994       0
------------------------------ Test Terminated --------------------------------

----------------------------- Statistics Screen ------- [1-9]: Change Screen --
  Start Time             | 2014-10-22   19:15:29.941276 1414030529.941276
  Last Reset Time        | 2014-10-22   19:25:15.056475 1414031115.056475
  Current Time           | 2014-10-22   19:25:15.564038 1414031115.564038
  Counter Name           | Periodic value            | Cumulative value
  Elapsed Time           | 00:00:00:507000           | 00:09:45:622000
  Call Rate              |    0.000 cps              |    1.708 cps
  Incoming call created  |        0                  |        0
  OutGoing call created  |        0                  |     1000
  Total Call created     |                           |     1000
  Current Call           |        6                  |
  Successful call        |        0                  |      994
  Failed call            |        0                  |        0
  Response Time 1        | 00:00:00:000000           | 00:00:01:670000
  Call Length            | 00:00:00:000000           | 00:00:31:673000
------------------------------ Test Terminated --------------------------------

Sippy_cup is definitely a good tool for all beginers who finds really hard time to work around with SIPp XML’s. I’m really excited to see how Docker is going to contirbute to VOIP world.

Docker, FreeSwitch, Ubuntu

Load Test on Docker Freeswitch – Part 1

Docker is a very powerfull tool for managing Linux containers. In my previous blog i’ve explaind on how to setup a Docker Freeswitch. Docker is very mature now, version 1.0 has already been released. Docker is now supported by all major cloud vendors. Docker was showing promising results when i was performing my initial testing. So this time i decided to perform a heavy load test on the Freeswitch container to ensure that Docker can really enter Telephony. Like any normal sys admin, i was googling for Freeswitch load test, and most of the results were pointing to Sipp, an Open Source test tool / traffic generator for the SIP protocol. For me Sipp didnt helped me as it started throwing errors beyond 320 simultaneous calls. The UDP connections were timing out. I tried increasing the timeout, which didn’t helped much.

So next choice is to use a Freeswitch itself, to generate calls. Using the FreeSwitch’s originate command to generate simultaneous calls and hit the Docker Freeswitch container. I also decided to collect all system metrics, so that i knows how the machine behaves under various load tests conditions. For this i deciced to use CollectD and Graphite combo. Collectd 5+ has an inbuild graphite plugin which can send the collectd metrics to a graphite server.

I’ve already setup an Ubuntu-Freeswitch Docker image. First we need to pull the images from the Docker hub.

$ docker pull deepakmdass88/fs-ubuntu

Now i’m going to start the Docker FreeSwitch container in foreground.

$ docker run --rm --privilieged -i -t -p 5060:5060/tcp -p 5060:5060/udp -p 16384:16384/udp -p 16385:16385/udp -p 16386:16386/udp -p 16387:16387/udp -p 16388:16388/udp -p 16389:16389/udp -p 16390:16390/udp -p 16391:16391/udp -p 16392:16392/udp -p 16393:16393/udp -p 5080:5080/tcp -p 5080:5080/udp deepakmdass88/fs-ubuntu /bin/bash

The privilieged option was enabled because, the FreeSwitch init script sets some custom ulimit values, so the container has to be given special privileges. Corresponding SIP and RTP ports are forwarded from the host to the container.

Now before starting the Freeswitch service, we can set up the CollectD agent. By default, the Ubuntu repostiry contains CollectD versio 4.10, but the Graphite plugin is available from version 5.0+ onwards. So we can use somne PPA which has the corresponding version available.

$ apt-get install python-software-properties

$ add-apt-repository ppa:joey-imbasciano/collectd5

$ apt-get update && apt-get install collectd

Now in the /etc/collectd.conf, uncomment LoadPlugin write_graphite. Also, in the same file and uncomment the plugin definition and fill in the server details.

<Plugin write_graphite>
        Host ""
        Port "2003"
        Protocol "tcp"
        LogSendErrors true
        Prefix "collectd."
        StoreRates true
        AlwaysAppendDS false
        EscapeCharacter "_"

I’ve enabled a custom freeswitch plugin, which will extract the current ongoing calls count from freeswitch and sends it to the graphite server. Once the config changes are done we can restart the CollectD service. Now we can check our graphite UI to see if the default metrics like memory, load, cpu etc. are reaching the graphite server. Once CollectD-Graphite setup is ready, we can go ahead with our load test. So, once the call has reached the server, we need some Dialplan to continue the calls. So the simplest method is to create an infinite loop of playing some file, or some conference. Below are some dialplans that i’ve created in the public.xml

# Infinite Play Loop

 <extension name="111222333">
       <condition field="destination_number" expression="^111222333$">
         <action application="answer"/>
         <action application="playback" data="sounds/music/8000/got.wav"/>
         <action application="transfer" data="111222333 XML public"/>

# Test conference

  <extension name="docker-fs-test-conf">
    <condition field="destination_number" expression="^112233">
      <action application="answer"/>
      <action application="sleep" data="500"/>
      <action application="conference" data="docker-test@public"/>

# Default IVR menu

    <extension name="ivr_demo">
      <condition field="destination_number" expression="^5000$">
        <action application="answer"/>
        <action application="sleep" data="2000"/>
        <action application="ivr" data="demo_ivr"/>

Now, we have the dialplans ready, next is authentication. By default there are two ways, Digest auth and IP Whitelist. Here i’m going to use IP whitelist, so we need to whitelist our IP in the acl.conf file.

 <list name="domains" default="deny">
      <!-- domain= is special it scans the domain from the directory to build the ACL -->
      <node type="allow" domain="$${domain}"/>
      <node type="allow" cidr=""/>                 # IP of FS from which we are going to send the calls
      <!-- use cidr= if you wish to allow ip ranges to this domains acl. -->
      <!-- <node type="allow" cidr=""/> -->

Now we can start the Freeswitch service.

$ /etc/init.d/freeswitch start

We can check the freeswich service using the fs_cli command.

$ /usr/local/freeswitch/bin/fs_cli -x "show status"

UP 0 years, 0 days, 6 hours, 34 minutes, 59 seconds, 648 milliseconds, 56 microseconds
FreeSWITCH (Version 1.5.13b git 39200cd 2014-07-02 21:55:21Z 64bit) is ready
1068 session(s) since startup
0 session(s) - peak 299, last 5min 0
0 session(s) per Sec out of max 30, peak 29, last 5min 0
1000 session(s) max
min idle cpu 0.00/100.00
Current Stack Size/Max 240K/8192K

Now freeswitch is ready to accept the connection. We can start sending the calls from our Load test freeswitch. Below is the script that was used to originate the calls from the load test Freeswitch machine. This will create simultaneous calls towards the Docker FS.


while [ 1 ]; do

set -i req
req=$(/usr/local/freeswitch/bin/fs_cli -q -b -x "show channels count" | awk '{print $1}')
if [ $req -lt $MAX_CALLS ]; then
    /usr/local/freeswitch/bin/fs_cli -q -b -x "bgapi originate sofia/external/$SIP_URI loadtest"
    echo "sleep a bit ..."
    sleep 10s


While bulk calls are being made from the Load test freeswitch machines, to test the Quality in real time, it’s better to dial to the extension directly from a Sip Phone/Client and ensure that voice quality is good. Below is my Graphite dashboard for the load test.

Default Graphite UI

Tessera UI

The FS was stable till 500 simultaneous calls, after that there was a sudden drop in calls and also the voice quality started dropping and in a minute the Freeswitch crashed due to Segmentation fault. I’m going to analyze the core dump file to understand more about the crash. The other smaller drops that we see in the graph was caused by the Load test Freeswitch machine, as the load was getting high when the number of calls was increased. But 500 simultaneous calls are pretty decent and the there was no issue in voice quality till the number of calls crossed 500. Though it’s very difficult to make a final confirmation, i decided to go ahead with phase 2 load test.

In the phase 2 test, i’m planning to use multiple FS load test machines to generate large simultaneous calls + running 2 separate FS containers on the same host and split the incoming calls to both these containers. Once the phase 2 test is completed, ill share the test results in an another blog post. Docker is still under heavy development, and i’m sure Docker will be entering Telephony soon.

Docker, FreeSwitch, Ubuntu, Voip

Dockerizing FreeSwitch – Docker Enters Telephony World

Docker has became one of the hottest topics in IT now a days. Docker is an open-source project that automates the deployment of applications inside software containers. Docker extends a common container format called Linux Containers (LXC), with a high-level API providing lightweight virtualization that runs processes in isolation.Docker uses LXC, cgroups, and the Linux kernel itself. Though i coudn’t make out to the DockerCon 2014 in SF, a lot new developments were announced on the DockerCon. Especially three new Opensource Projects libcontainer, libchan and libswarn. Docker is indeed creating a revolution in the container space, creating a next generation of scalable platform management. There are a lot PAAS services like Deis,, Dokku which are already using Docker in production. Another important and exciting project is CoreOS. CoreOS uses tools like SystemD, Fleet, EtcD to build a fully scalabale docker based cluster management system. I definitely need a separate blog to write about CoreOS, it’s really a super exciting project to play with.

Last week Docker Team released Version 1.0 of Docker. So i’ll be using the same in this new set up. It’s been almost 6 Month’s since i’ve been working @ Plivo as a DevOps Engineer. Telephony was really a very new platform for me. And my first companion was offcourse FreeSwitch,a scalable open source cross-platform telephony platform designed to route and interconnect popular communication protocols using audio, video, text or any other form of media. I was heavily using Vagrant for all my experiments in my mac. But after started using Docker, it really made me crazy. I’ve played for some time wiht LXC’s long back. So this was like a leap back to the container world.

There are a lot of concerns on using Virtual Machines in Telephony world. Especially for the server’s that handles the Real Time voice packets, as voice quality is pretty important in Telephony. Docker’s again more light weight isolated environment, and i decide to see how Docker can perform with such issues. If Docker handle Freeswitch smoothly, then i’m sure that we can use Docker for other telephony app’s like OpenSIPS/Kamailio etc, as they handle only sessions not the Media traffic. I know there are a lot of concerns like CPU load, Network etc, but this is like an initial move to test Docker into Telephony.

Setting Up Docker

Docker 1.0 is available from the Official Docker repo.

$ echo "deb docker main" > /etc/apt/sources.list.d/docker.list

$ apt-get update && apt-get install lxc-docker

Now we can check the Docker version using the docker binary itself.

$ docker version

Client version: 1.0.0
Client API version: 1.12
Go version (client): go1.2.1
Git commit (client): 63fe64c
Server version: 1.0.0
Server API version: 1.12
Go version (server): go1.2.1
Git commit (server): 63fe64c

Now Docker is installed, but we need some OS images to use with docker. We can build custom images using debootstrap etc. But there are official minimal images available in Docker HUB. We can search for the repositories and can pull those images via docker binary itself.

For example to pull the entire Ubuntu images, we can just do,

$ docker pull ubuntu

But this will download all the ubuntu images available in the repo. We can also do selective download by using the tag.

$ docker pull ubuntu:14:04

Once the images are downloaded, we can use images option in docker binary to see all the downloaded images.

$ docker images

REPOSITORY                      TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
ubuntu                          14.04               ad892dd21d60        10 days ago         275.5 MB

Here i’m not going to daemonize the container, i’ll be using the interactive option. But first, let’s start a new container.

$ docker run -t -i ubuntu:14.04 /bin/bash

This command will start a conatiner and will open up a bash session for us and we will be inside the bash session. Now to use an application we need to open up corresponding ports to outside world. We can use the “-p” option while starting a docker container to enable port forwarding. Under the hood, docker is using IPtables for the same. In the case of Freeswitch, we need to open 5060,5080 for the default Sofia profiles (Internal and External). Also we need to open the RTP ports. In this test i’ll be opening a predefined set of ports ie from “16384” to “16394”. (As my Docker host resides on Azure, creating an Endpoint for each port forward is really a pain, so i decided to open only a few). And also i’ll be opening port 22, so that we can have an ssh server inside the container.

$ docker run -t -i -p 2223:22 -p 5060:5060/tcp -p 5060:5060/udp -p 16384:16384/udp -p 16385:16385/udp -p 16386:16386/udp -p 16387:16387/udp -p 16388:16388/udp -p 16389:16389/udp -p 16390:16390/udp -p 16391:16391/udp -p 16392:16392/udp -p 16393:16393/udp -p 5080:5080/tcp -p 5080:5080/udp ubuntu:14.04 /bin/bash

This will start a new container and Docker by default will setup the IPtables for port forwarding. So now my IPtables looks like this.

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination
   43 16850 ACCEPT     udp  --  !docker0 docker0             udp dpt:5080
    0     0 ACCEPT     tcp  --  !docker0 docker0             tcp dpt:5080
  988  198K ACCEPT     udp  --  !docker0 docker0             udp dpt:16392
    0     0 ACCEPT     udp  --  !docker0 docker0             udp dpt:16389
    0     0 ACCEPT     udp  --  !docker0 docker0             udp dpt:16385
    0     0 ACCEPT     udp  --  !docker0 docker0             udp dpt:16393
 2026  405K ACCEPT     udp  --  !docker0 docker0             udp dpt:16388
 8817 1763K ACCEPT     udp  --  !docker0 docker0             udp dpt:16384
12144 8684K ACCEPT     udp  --  !docker0 docker0             udp dpt:5060
 4359  257K ACCEPT     tcp  --  !docker0 docker0             tcp dpt:5060
 9917 1983K ACCEPT     udp  --  !docker0 docker0             udp dpt:16390
    0     0 ACCEPT     udp  --  !docker0 docker0             udp dpt:16387
    0     0 ACCEPT     tcp  --  !docker0 docker0             tcp dpt:22
   38  4848 ACCEPT     udp  --  !docker0 docker0             udp dpt:16391
    1   152 ACCEPT     udp  --  !docker0 docker0             udp dpt:16386
    0     0 ACCEPT     all  --  *      lxcbr0  
    0     0 ACCEPT     all  --  lxcbr0 *  
 431K  630M ACCEPT     all  --  *      docker0              ctstate RELATED,ESTABLISHED
 128K   19M ACCEPT     all  --  docker0 !docker0  
   16  2460 ACCEPT     all  --  docker0 docker0  

Now we can go ahead with Freeswitch compilation. In my previous blog, i’ve mentioned how to compile and set up freeswitch. Once freeswitch is ready, we need to make a few changes. By default, Freeswitch uses STUN to route through NAT, but this doesn’t work with Docker. So we have to set the external IP manually. In the Freeswitch installed folder, edit conf/autoload_configs/switch.conf.xml. In this file we can set the External IP manually. Add the below lines to switch_conf.xml.

<X-PRE-PROCESS cmd="set" data="external_sip_ip=<YOUR_EXTERNAL_IP>"/>
<X-PRE-PROCESS cmd="set" data="external_rtp_ip=<YOUR_EXTERNAL_IP>"/>

Also we need to modify the Default Sofia Profiles and need to set the ext-rtp-ip and ext-sip-ip to use our external IP added in the switch_conf.xml file while establishing connections. Add the below lines to the conf/sip_profiles/internal.xml and conf/sip_profiles/external.xml

<param name="ext-rtp-ip" value="$${external_rtp_ip}"/>
<param name="ext-sip-ip" value="$${external_sip_ip}"/>

Now we need to set teh RTP ip range to the range which we have forwarded while creting the container. So we need to edit conf/autoload_configs/switch.conf.xml

<param name="rtp-start-port" value="16384"/>
<param name="rtp-end-port" value="16394"/>

Once the changes are made, we can start the FreeSwitch service. Now to make sure that the External IP is working properly, we can check the sofia profile status using fs_cli. below is a sample output of the sofia profile status.

freeswitch@internal> sofia status profile internal
Name                internal
Domain Name         N/A
Auto-NAT            false
DBName              sofia_reg_internal
Pres Hosts,
Dialplan            XML
Context             public
Challenge Realm     auto_from
Ext-RTP-IP          <my_external_ip>
Ext-SIP-IP          <my_external_ip>
URL                 sip:mod_sofia@<my_external_ip>:5060
BIND-URL            sip:mod_sofia@<my_external_ip>:5060;maddr=;transport=udp,tcp
HOLD-MUSIC          local_stream://moh
TEL-EVENT           101
DTMF-MODE           rfc2833
CNG                 13
SESSION-TO          0
MAX-DIALOG          0
NOMEDIA             false
LATE-NEG            true
PROXY-MEDIA         false
ZRTP-PASSTHRU       true
CALLS-IN            0
CALLS-OUT           0

Now freeswitch ahs started successfully. We can test some basic calls using softphones like Xlite, Telephone etc. By default, there are some default extensions and user’s available, so we can use the same for testing the calls. But i really wanted to try trunkning also and wanted to see the quality of the voice. So i created SIP trunking in Freeswitch using Plivo. And i tested a couple of calls to US and India DID’s and no issues were detected in the quality. But again i need to test the laod of the server’s when it startes handling concurrent calls and also the voice quality. But i decied to d oit as a Phase II. But as of now, Docker FreeSwitch is working perfectly like a physical machine with out issues.

So now we have a working FreeSwitch container, now here comes the main advantage of the Docker. We can create a new image with all these changes, so that nex time i dont need to work from scratch. I can use this saved image and a readymade Docker Freeswitch container can be launched in seconds. Since we are in interactive mode, we should not quit the session before it’s saved or else all the things will be lost,becoz dokcer will destroy the same. So open up a new shell on the docker host and use the commit option. But to use the commit command, we need to know the container id, so here docker ps command comes handy.

$ docker ps

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS           NAMES

e7f3c02346d4        a4196763d248        /bin/bash           32 hours ago        Up 32 hours>22/tcp,>5060/tcp,>5060/udp,>5080/tcp,>5080/udp,>16384/udp,>16385/udp,>16386/udp,>16387/udp,>16388/udp,>16389/udp,>16390/udp,>16391/udp,>16392/udp,>16393/udp   silly_turing

In my case “e7f3c02346d4” is the container ID. So i can use the same for commit. I won’t be commiting to the base Ubuntu image, as i can use the same for other purposes, so here i’ll commiting to a new image say “ubntu-fs-docker”

$ docker commit -m "<commit message>" e7f3c02346d4 ubntu-fs-docker

Now we can use this “ubntu-fs-docker” image to launch a ready made FreeSwitch server’s.

Docker is a very juvenile project about more than a year old. But the use cases are expanding heavily in the Modern IT world. Docker is fueling up a new generation of scalable servers. Wishing all the best for Docker and kudos to Solomon Hykes and the DotCloud team for opensourcing such a powerfull project

FreeSwitch, kamailio, SIP

Integrating Kamailio with FreeSwitch

Kamailio aka OpenSER is one of the most powerfull and popular Open Source SIP server. It can be used as SIP Proxy/ Registrar/ LB/ Router etc. It also provides a lot of features like WebSocket support for WebRTC, ; SIMPLE instant messaging and presence with embedded XCAP server and MSRP relay,IMS extensions,ENUM and offcourse AAA (accounting, authentication and authorization) also. Kamailio is a modular system, ie, it has lot of modules which corresponds to particular functions. These modules can be easily installed and can be used easily in Kamailio. In this blog i’m going to use Kamailio as a proxy server. All the user’s are created in the Kamailio and FreeSwitch will be acting as a relay server for outbound calls. So Kamailio performs authentication and all the outbound calls wil be relayed to FreeSwitch.

Installing Kamailio

Lets download the latest version of Kamailio, now it’s 4.1

$ wget

$ tar xvzf Kamailio-4.1.1_src.tar.gz && cd Kamailio-4.1.1

Before we start the build we need to install the basic dependencies.

$ apt-get install gcc flex bison libmysqlclient-dev make libxml2-dev libssl-dev

Now we have the dependencies installed, we can go ahead with the build.

$ make cfg      # generates config files for build system

Now open modules.lst and add the modules to be installed in ”include_modules” section. In my case i’m going to use MySQL backend so it will be ”include_modules= db_mysql” and then we can run the ”make all”. The other way is we can mention the modules directly while running the “make” rather editing the modules.lst file.

$ make include_modules="db_mysql" cfg

Now we can install,

$ make install

The above command will install Kamailio to our system. There are four main binaries for Kamailio,

Kamailio - Kamailio SIP server
kamdbctl - script to create and manage the Databases
kamctl - script to manage and control Kamailio SIP server
kamcmd - CLI - command line tool to interface with Kamailio SIP server

There is also one configuration file called “Kamailio.cfg” which is available by default at /usr/local/etc/Kamailio/Kamailio.cfg

Let’s go ahead with setting up MySQL server for Kamailio.

$ apt-get install mysql-server

Now edit the /usr/local/etc/Kamailio/kamctlrc Locate DBENGINE variable and set it to MYSQL by making ”DBENGINE=MYSQL”. Now we can use the “kamdbctl” binary to craete the default tables and users.

$ /usr/local/sbin/kamdbctl create

The script will add two users in MySQL:

  • Kamailio – (with default password ‘Kamailiorw’) – user which has full access rights to ‘Kamailio’ database

  • Kamailioro – (with default password ‘Kamailioro’) – user which has read-only access rights to ‘Kamailio’ database

There is a sample init.d script available along with Kamailio, which we can use it. We need to copy the sample init.d file to our system’s init.d folder. And the same for the system default file.

$ cp /usr/local/src/Kamailio-4.1.1/pkg/Kamailio/deb/precise/Kamailio.init /etc/init.d/Kamailio

$ cp /usr/local/src/Kamailio-4.1.1/pkg/Kamailio/deb/precise/Kamailio.default /etc/default/Kamailio

$ chmod 755 /etc/init.d/Kamailio 

Edit the new init file and modify the $DAEMON and $CFGFILE values.


$ mkdir -p /var/run/Kamailio    # Directory for the pid file

Default setting is to run Kamailio as user ”Kamailio” and group ”Kamailio”. For that we need to create the user:

$ adduser --quiet --system --group --disabled-password \
      --shell /bin/false --gecos "Kamailio" \
      --home /var/run/Kamailio Kamailio

$ chown Kamailio:Kamailio /var/run/Kamailio

Setting up Kamailio

All the Kamailio configurations are mentioned in only one single file /usr/local/etc/Kamailio/Kamailio.cfg. All the logics are defined in this file, and Kamailio blindly executes this logics and perform the actions. It’s very important that the logics defined in the config should suit to our VOIP platform requirement.

First we need to enable the modules and the necessary features, so add the below lines in the Kamailio.cfg

#!define WITH_MYSQL
#!define WITH_AUTH

We need to define the FreeSwitch server IP and port, for that we can add the below parameters in the “Custom Parameters” section.

freeswitch.bindip = "" desc "FreeSWITCH IP Address"
freeswitch.bindport = "5090" desc "FreeSWITCH Port"

Now we can go ahead to the ”request_route” section which performs the routing logic. Here i’m going to add two more routing logic for the FreeSwitch relay. After the ”request_route” section, we can see the definition for each routing options. Below that we need to add our new route definitions.

        # dial number selection

route[FSRELAY] {
        $du = "sip:" + $sel(cfg_get.freeswitch.bindip) + ":" + $sel(cfg_get.freeswitch.bindport);
                $var(newbranch) = 0;

By default, all the routes mentioned in the “request_route” will be executed line by line. There is a default route called ”Location”, which splits the user part from the request URI and verifies if the user exists in the location table. But when we dial an outside number/user, this location check will fail, so i’m going to add a condition which checks if the user in the request URI contains a number with a length 9-15 will be relayed to the FreeSwitch. Again this is just a simple condition, we can create a more complex condition, like check the domain part, if the domain part contains a domain which doesnot belong to our Domain list, we can either decline the request, or we can relay to FreeSwitch or we can make DNS query and we can make Kamailio to process the request to that domain’s Proxy server. Like this we can define our own conditions in the config file, and Kamailio will execute it line by line.

I’m going to add my check condition on the ”LOCATION” route definition.

route[LOCATION] {

    #!ifdef WITH_SPEEDDIAL
        # search for short dialing - 2-digit extension
        if($rU=~"^[0-9]{9,15}$")        # checking for numbers in the Request URI
    #!ifdef WITH_ALIASDB
        # search in DB-based aliases
        $avp(oexten) = $rU;
        if (!lookup("location")) {
                xlog("L_INFO", "CALL $rm $ci lookup here\n");
                xlog("L_INFO", "$fU@$fd - Lookup contact location for $rm\n");
                xlog("L_INFO", "rc is $var(rc)");
                switch ($rc) {
                        case -1:
                        case -3:
                                xlog("L_ERR", "$fU@$fd - No contact found\n");
                                send_reply("404", "Not Found here");
                        case -2:
                                send_reply("405", "Method Not Allowed");

        # when routing via usrloc, log the missed calls also
        if (is_method("INVITE"))
        xlog("L_INFO", "CALL $rm $ci relay\n");
        xlog("L_INFO", "$fU@$fd - Relaying $rm\n");

So now all the calls coming with numbers of length 9-15 in the Request URI will be relayed to the FreeSwitch, and FreeSwitch will process the call based on the DialPlan configured in the FreeSwitch. Since i’m going to use IP authentication, i need to whitelist the Kamailio ip in “acl_conf.xml” file in the FreeSwitch autload conf directory, so that FreeSwitch will accept the invites from Kamailio. Again i’m not defining any Voicemail options here. If we have a Voice mail server, then we can create another route option and when the caller doesn’t pick the call we can route the call to the Voice Mail server.
For example the below condition will route the failures to FreeSwitch Voice Mailbox.

            # in case of failure - re-route to FreeSWITCH VoiceMail
            t_on_failure("FAIL_FSVBOX");        # where FSVBOX is a route definition

Kamailio has a lot of modules which really comes in handy. For example we can use LDAP module to use LDAP as a backend. There is a PRESENCE module which helps us to setup an Instant Messaging server using Kamailio. I’ll be writing a blog on how to use Kamailio as an IM server soon. One of the main advantage of Kamailio over OpenSIP is the WebSocket support. This just a basic configuration, but we can design much complex system using Kamailio. We can even remove the default route logics, and we can use our own routing logics. Kamailio doesnot depend on default routing logics, it blindly reads the route and executes it for each incoming connections.