pdb Module

Hardy Kahl

1&1 Internet AG

Edited by

Henning Westerholt

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. Parameters
3.1. timeout (integer)
3.2. server (string)
4. 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

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

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. Parameters

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,")

4. Functions

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

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