pdb Module

Hardy Kahl

   1&1 Internet AG

Edited by

Henning Westerholt

   1&1 Internet AG
   <henning.westerholt@1und1.de>

   Copyright © 2009 1&1 Internet AG
     __________________________________________________________________

   Table of Contents

   1. Admin Guide

        1. Overview
        2. Dependencies

              2.1. Kamailio Modules
              2.2. External Libraries or Applications

        3. Exported Parameters

              3.1. timeout (integer)
              3.2. server (string)

        4. Exported Functions

              4.1. pdb_query (string query, string dstavp)

        5. MI Commands

              5.1. pdb_status
              5.2. pdb_activate
              5.3. pdb_deactivate

   List of Examples

   1.1. Set timeout parameter
   1.2. Set server parameter
   1.3. pdb_query usage
   1.4. pdb_status usage
   1.5. pdb_activate usage
   1.6. pdb_deactivate usage

Chapter 1. Admin Guide

   Table of Contents

   1. Overview
   2. Dependencies

        2.1. Kamailio Modules
        2.2. External Libraries or Applications

   3. Exported Parameters

        3.1. timeout (integer)
        3.2. server (string)

   4. Exported Functions

        4.1. pdb_query (string query, string dstavp)

   5. MI Commands

        5.1. pdb_status
        5.2. pdb_activate
        5.3. pdb_deactivate

1. Overview

   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.

   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.

2. Dependencies

   2.1. Kamailio Modules
   2.2. External Libraries or Applications

2.1. Kamailio Modules

   The module depends on the following modules (in the other words the
   listed modules must be loaded before this module):
     * none

2.2. External Libraries or Applications

   The following libraries or applications must be installed before
   running Kamailio with this module loaded:
     * The PDB server

3. Exported Parameters

   3.1. timeout (integer)
   3.2. server (string)

3.1. timeout (integer)

   This is the timeout in milliseconds for the pdb_query function.

   Default value is “50”.

   Example 1.1. Set timeout parameter
...
modparam("pdb", "timeout", 10)
...

3.2. server (string)

   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.

   Example 1.2. Set server parameter
...
modparam("pdb", "server", "localhost:10001,host.name:10001,192.168.1.7:10002")
...

4. Exported Functions

   4.1. pdb_query (string query, string dstavp)

4.1.  pdb_query (string query, string dstavp)

   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.

   Example 1.3. pdb_query usage
...
# 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");
...

5. MI Commands

   5.1. pdb_status
   5.2. pdb_activate
   5.3. pdb_deactivate

5.1.  pdb_status

   Prints the status of the module. This can either be "active" or
   "deactivated".

   Example 1.4. pdb_status usage
...
kamctl fifo pdb_status
...

5.2.  pdb_activate

   Activates the module. This is the default after loading the module.

   Example 1.5. pdb_activate usage
...
kamctl fifo pdb_activate
...

5.3.  pdb_deactivate

   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.

   Example 1.6. pdb_deactivate usage
...
kamctl fifo pdb_deactivate
...