QOS Module

Ovidiu Sas

   SOMA Networks, Inc.

Edited by

Ovidiu Sas

   Copyright © 2008 SOMA Networks, Inc.
     __________________________________________________________________

   Table of Contents

   1. Admin Guide

        1. Overview
        2. How it works
        3. Dependencies

              3.1. Kamailio Modules
              3.2. External Libraries or Applications

        4. Parameters

              4.1. qos_flag (integer)

        5. Functions
        6. Statistics
        7. Exported pseudo-variables
        8. Installation and Running

   2. Developer Guide

        1. Available Functions

              1.1. register_qoscb (qos, type, cb, param)

   List of Examples

   1.1. Set qos_flag parameter

Chapter 1. Admin Guide

   Table of Contents

   1. Overview
   2. How it works
   3. Dependencies

        3.1. Kamailio Modules
        3.2. External Libraries or Applications

   4. Parameters

        4.1. qos_flag (integer)

   5. Functions
   6. Statistics
   7. Exported pseudo-variables
   8. Installation and Running

1. Overview

   The qos module provides a way to keep track of per dialog SDP
   session(s).

2. How it works

   The qos module uses the dialog module to be notified of any new or
   updated dialogs. It will then look for and extract the SDP session (if
   present) from SIP requests and replies and keep track of it for the
   entire life of a dialog.

   All of this happens with a properly configured dialog and qos module
   and setting the dialog flag and the qos flag at the time any INVITE SIP
   message is seen. There is no config script function call required to
   set the SDP session tracking mechanism. See the dialog module users
   guide for more information.

   A dialog can have one or more SDP sessions active in one of the
   following states:
     * pending - only one endpoint of the SDP session is known.
     * negotiated - both endpoints of the SDP session are known.

   An SDP session can be established in one of the following scenarios:
     * INVITE/200ok - typical "INVITE" and "200 OK" SDP exchange.
     * 200ok/ACK - "200 OK" and "ACK" SDP exchange (for calls starting
       with an empty INVITE).
     * 183/PRACK - early media via "183 Session Progress" and "PRACK" (see
       RFC 3959 for more information) - not implemented yet.

3. Dependencies

   3.1. Kamailio Modules
   3.2. External Libraries or Applications

3.1. Kamailio Modules

   The following modules must be loaded before this module:
     * dialog - dialog module and its dependencies (tm).

3.2. External Libraries or Applications

   The following libraries or applications must be installed before
   running Kamailio with this module loaded:
     * None.

4. Parameters

   4.1. qos_flag (integer)

4.1. qos_flag (integer)

   The module will not do anything to any message unless instructed to do
   so via the config script. You must set the qos_flag value in the
   setflag() call of the INVITE you want the qos module to process. But
   before you can do that, you need to tell the qos module which flag
   value you are assigning to qos.

   In most cases when ever you set the dialog flag you will want to set
   the qos flag. If the dialog flag is not set and the qos flag is set, it
   will not have any effect.

   This parameter must be set or the module will not load.

   Default value is “Not set!”.

   Example 1.1. Set qos_flag parameter
...
modparam("dialog", "dlg_flag", 5)
modparam("qos", "qos_flag", 7)
...
route {
  ...
  if (method=="INVITE") {
    setflag(5); # set the dialog flag
    setflag(7); # Set the qos flag
  }
  ...
}

5. Functions

   There are no exported functions that could be used in scripts.

6. Statistics

   There are no exported statistics for the qos module.

7. Exported pseudo-variables

   There are no exported pseudo-variables for the qos module.

8. Installation and Running

   Just load the module and remember to set the flag.

Chapter 2. Developer Guide

   Table of Contents

   1. Available Functions

        1.1. register_qoscb (qos, type, cb, param)

1. Available Functions

   1.1. register_qoscb (qos, type, cb, param)

1.1.  register_qoscb (qos, type, cb, param)

   Register a new callback to the qos.

   Meaning of the parameters is as follows:
     * struct qos_ctx_st* qos - qos to register callback to. It may be
       NULL only for QOSCB_CREATED callback type, which is not a per qos
       type.
     * int type - types of callbacks; more types may be registered for the
       same callback function; only QOSCB_CREATED must be registered
       alone. Possible types:
          + QOSCB_CREATED - called when a new qos context is created -
            it's a global type (not associated to any qos).
          + QOSCB_ADD_SDP - called when a new SDP was added to the qos
            context - it's a per qos type.
          + QOSCB_UPDATE_SDP - called when an existing SDP is updated -
            it's a per qos type.
          + QOSCB_REMOVE_SDP - called when an existing SDP is removed -
            it's a per qos type.
          + QOSCB_TERMINATED - called when the qos is terminated.
     * qos_cb cb - callback function to be called. Prototype is: “void
       (qos_cb) (struct qos_ctx_st *qos, int type, struct qos_cb_params
       *params); ”
     * void *param - parameter to be passed to the callback function.
