<div>Hi dear FS community,</div><div><br></div><div>After a brief analysis of 2 solutions using OpenSIPS and <span class="Apple-style-span" style="font-family: sans-serif; font-size: 13px; line-height: 19px; ">Kamailio </span>(<a href="http://www.opensips.org/html/docs/modules/devel/load_balancer.html#id226109">http://www.opensips.org/html/docs/modules/devel/load_balancer.html#id226109</a> ) and (<a href="http://wiki.freeswitch.org/wiki/SBC_Setup">http://wiki.freeswitch.org/wiki/SBC_Setup</a>) I decided to implement my own solution using ONLY FreeSWITCH and ONLY 1 table of any database server (we use MySQL).</div>
<div><br></div><div>It works on few of our servers right now without any issues.</div><div><br></div><div>Feel free to reuse / improve it or provide your comments if you see something wrong with it.</div><div><br></div><div>
<br></div><div>We have one routing server (RS) and several Media Servers (MS).</div><div>FreeSWITCH is installed on each server in default configuration.</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>--> MS_1</div>
<div>RS --> MS_2</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>--> MS_N</div><div><br></div><div><br></div><div>(Failover can be implemented by adding one more routing server, but this is out of scope of current description).</div>
<div><br></div><div>Routing server routes calls to media servers based on logic that you can easily define.</div><div>(Generally speaking, Routing server can route part of the calls onto itself, but to simplify let's say that it will route only to Media Servers).</div>
<div><br></div><div><br></div><div>Routing server is used to register subscribers (it will have directory files ./freeswitch/conf/directory/default/10001whatever.xml-99999whatever.xml).</div><div>Media servers do NOT contain files with users (security issue? probably should be managed on dialplan stage of media servers by comparing ip addresses of requests).</div>
<div><br></div><div><br></div><div>The whole routing can be presented by the following chain:</div><div><br></div><div>Call arrives into Default context-->RS default dialplan-->Lua script-->PHP script to get destination MEDIA SERVER IP-->back to Lua script-->Bridge "sofia/external/" to determined MS IP address-->[Bridge to fail over media server, optionally]-->End</div>
<div><br></div><div>Let's say we need to route all international calls based on less loaded server (other logic can be easily implemented in PHP script as well).</div><div><br></div><div><u>1. RS Dialplan: default.xml</u></div>
<div><include></div><div> <extension name="route"></div><div> <condition field="destination_number" expression="^(00)(\d+)"></div><div> <action application="lua" data="route.lua $2"/></div>
<div> </condition></div><div> </extension> </div><div></include> </div><div><br></div><div><br></div><div><u>2. RS Lua script: route.lua</u></div><div>called_number = argv[1]; //without "00"</div>
<div>api = freeswitch.API();</div><div>server_ip_address = api:executeString("curl <a href="http://localhost/get_server_ip.php">http://localhost/get_server_ip.php</a>);</div><div>forwarding_session_string = "sofia/external/"..called_number.."@"..server_ip_address;</div>
<div>session:setVariable("bypass_media", "true"); //described below!!!</div><div>session:execute("bridge",forwarding_session_string);</div><div><br></div><div><u>3. PHP script: get_server_ip.php</u></div>
<div><<< ANY PHP CODE THAT WILL QUERY COMMON DATABASE AND WILL DETERMINE LESS LOADED AT THE MOMENT SERVER>>></div><div>die($less_loaded_server_ip);</div><div><br></div><div><br></div><div>All Media Servers should provide information about their current load into one common database (dedicated server or routing server can be used for database).</div>
<div>If you use scripts you can update this table on starting a call and after call finished.</div><div>Or you can create a job that will query FreeSWITCH and will update the database every, say, 10 seconds.</div><div><br>
</div><div><br></div><div>Basically that's all (really!)</div><div>I beleive it can be used for most general purpose scenarios without need of third-party tools.</div><div><br></div><div>P.S. </div><div>The only problem we had from the beginning was that RTP media traffic was passing thru both servers: RS and Media Server.</div>
<div>But after we added the following command to the routing script, RTP media traffic started to pass only thru Media server, making RS almost free.</div><div>session:setVariable("bypass_media", "true");</div>
<div><br></div><div><br></div><div><br></div><div>Best regards,</div><div>vIT</div><div><br></div>