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"http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
<!ENTITY % docentities SYSTEM "../../../docbook/entities.xml">
%docentities;
]>
<chapter>
<title>&adminguide;</title>
<section>
<title>Overview</title>
<para>
This is a module for fast number portability handling. The client is this module
and the server exists in the /utils/pdbt directory.
The PDB module and server supports load-balancing and aggressive timeouts.
Normally it does not need more than a few ms to query the remote server and return
the reply to the configuration script.
</para>
<para>
The pdb module allows &kamailio; to send queries to a list of servers
and store the answer in an AVP. The idea is to ask all servers in
parallel and use the first answer, that comes back. A timeout for the
query can be defined in milliseconds. The queying can be activated and
deactivated using FIFO commands.
</para>
</section>
<section>
<title>Dependencies</title>
<section>
<title>&kamailio; Modules</title>
<para>
The module depends on the following modules (in the other words
the listed modules must be loaded before this module):
</para>
<itemizedlist>
<listitem>
<para><emphasis>none</emphasis></para>
</listitem>
</itemizedlist>
</section>
<section>
<title>External Libraries or Applications</title>
<para>
The following libraries or applications must be installed
before running &kamailio; with this module loaded:
</para>
<itemizedlist>
<listitem>
<para><emphasis>The PDB server</emphasis></para>
</listitem>
</itemizedlist>
</section>
</section>
<section>
<title>Parameters</title>
<section>
<title><varname>timeout</varname> (integer)</title>
<para>
This is the timeout in milliseconds for the pdb_query function.
</para>
<para>
<emphasis>
Default value is <quote>50</quote>.
</emphasis>
</para>
<example>
<title>Set <varname>timeout</varname> parameter</title>
<programlisting format="linespecific">
...
modparam("pdb", "timeout", 10)
...
</programlisting>
</example>
</section>
<section>
<title><varname>server</varname> (string)</title>
<para>
This is the list of servers to be used by the pdb_query function.
Queries will be sent in parallel to all servers configured in this list.
This parameter is mandatory.
</para>
<example>
<title>Set <varname>server</varname> parameter</title>
<programlisting format="linespecific">
...
modparam("pdb", "server", "localhost:10001,host.name:10001,192.168.1.7:10002")
...
</programlisting>
</example>
</section>
</section>
<section>
<title>Functions</title>
<section>
<title>
<function moreinfo="none">pdb_query (string query, string dstavp)</function>
</title>
<para>
Sends the query string to all configured servers and stores the answer in
dstavp. If it takes more than the configured timeout, false is returned.
Pseudo-variables or AVPs can be used for the query string.
The answer must consist of the null terminated query string followed by
a two byte integer value in network byte order. The integer value will
be stored in the given AVP.
</para>
<example>
<title><function>pdb_query</function> usage</title>
<programlisting format="linespecific">
...
# query external service for routing information
if (!pdb_query("$rU", "$avp(i:82)"))
$avp(i:82) = 0; # default routing
}
cr_route("$avp(i:82)", "$rd", "$rU", "$rU", "call_id");
...
</programlisting>
</example>
</section>
</section>
<section>
<title><acronym>MI</acronym> Commands</title>
<section>
<title>
<function moreinfo="none">pdb_status</function>
</title>
<para>
Prints the status of the module.
This can either be "active" or "deactivated".
</para>
<example>
<title><function>pdb_status</function> usage</title>
<programlisting format="linespecific">
...
&ctltool; fifo pdb_status
...
</programlisting>
</example>
</section>
<section>
<title>
<function moreinfo="none">pdb_activate</function>
</title>
<para>
Activates the module. This is the default after loading the module.
</para>
<example>
<title><function>pdb_activate</function> usage</title>
<programlisting format="linespecific">
...
&ctltool; fifo pdb_activate
...
</programlisting>
</example>
</section>
<section>
<title>
<function moreinfo="none">pdb_deactivate</function>
</title>
<para>
Deactivates the module. No more queries are performed until it is
activated again. As long as the module is deactivated, the
pdb_query function will return -1.
</para>
<example>
<title><function>pdb_deactivate</function> usage</title>
<programlisting format="linespecific">
...
&ctltool; fifo pdb_deactivate
...
</programlisting>
</example>
</section>
</section>
</chapter>
|
