1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

     2 /*

     3  * Copyright (c) 2007 INRIA

     4  *

     5  * This program is free software; you can redistribute it and/or modify

     6  * it under the terms of the GNU General Public License version 2 as

     7  * published by the Free Software Foundation;

     8  *

     9  * This program is distributed in the hope that it will be useful,

    10  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    12  * GNU General Public License for more details.

    13  *

    14  * You should have received a copy of the GNU General Public License

    15  * along with this program; if not, write to the Free Software

    16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    17  *

    18  * Authors: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

    19  */

    20 #ifndef DELAY_JITTER_ESTIMATION_H

    21 #define DELAY_JITTER_ESTIMATION_H

    22 

    23 #include "ns3/nstime.h"

    24 #include "ns3/packet.h"

    25 

    26 namespace ns3 {

    27 

    28 /**

    29  * \ingroup stats

    30  *

    31  * \brief quick and dirty delay and jitter estimation

    32  *

    33  */

    34 class DelayJitterEstimation

    35 {

    36 public:

    37   DelayJitterEstimation ();

    38 

    39   /**

    40    * \param packet the packet to send over a wire

    41    *

    42    * This method should be invoked once on each packet to

    43    * record within the packet the tx time which is used upon

    44    * packet reception to calculate the delay and jitter. The

    45    * tx time is stored in the packet as an ns3::Tag which means

    46    * that it does not use any network resources and is not

    47    * taken into account in transmission delay calculations.

    48    */

    49   static void PrepareTx (Ptr<const Packet> packet);

    50   /**

    51    * \param packet the packet received

    52    *

    53    * Invoke this method to update the delay and jitter calculations

    54    * After a call to this method, \ref GetLastDelay and \ref GetLastJitter

    55    * will return an updated delay and jitter.

    56    */

    57   void RecordRx (Ptr<const Packet> packet);

    58 

    59   /**

    60    * \returns the updated delay.

    61    */

    62   Time GetLastDelay (void) const;

    63   /**

    64    * The jitter is calculated using the RFC 1889 (RTP) jitter

    65    * definition.

    66    *

    67    * \returns the updated jitter.

    68    */

    69   uint64_t GetLastJitter (void) const;

    70 

    71 private:

    72   Time m_previousRx;

    73   Time m_previousRxTx;

    74   int64x64_t m_jitter;

    75   Time m_delay;

    76 };

    77 

    78 } // namespace ns3

    79 

    80 #endif /* DELAY_JITTER_ESTIMATION_H */