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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
* Copyright (c) 2009, 2010 MIRKO BANCHI
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation;
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Mirko Banchi <mk.banchi@gmail.com>
* Author: Tommaso Pecorella <tommaso.pecorella@unifi.it>
*/
#ifndef ORIGINATOR_BLOCK_ACK_AGREEMENT_H
#define ORIGINATOR_BLOCK_ACK_AGREEMENT_H
#include "block-ack-agreement.h"
namespace ns3 {
/**
* \ingroup wifi
* Maintains the state and information about transmitted MPDUs with ack policy block ack
* for an originator station.
*/
class OriginatorBlockAckAgreement : public BlockAckAgreement
{
friend class BlockAckManager;
public:
OriginatorBlockAckAgreement ();
OriginatorBlockAckAgreement (Mac48Address recipient, uint8_t tid);
~OriginatorBlockAckAgreement ();
/* receive ADDBAResponse
* send ADDBARequest --------------- status code = success ---------------
* ----------------->| PENDING |------------------------>| ESTABLISHED |-----
* --------------- --------------- |
* | / ^ ^ |
* receive ADDBAResponse | receive BlockAck / | | | receive BlockAck
* status code = failure | retryPkts + queuePkts / | | | retryPkts + queuePkts
* v < / | | | >=
* --------------- blockAckThreshold / | | | blockAckThreshold
* | UNSUCCESSFUL | / | | |
* --------------- v | ----------|
* -------------- |
* | INACTIVE | |
* -------------- |
* send a MPDU (Normal Ack) | |
* retryPkts + queuePkts | |
* >= | |
* blockAckThreshold |----------------
*/
/**
* Represents the state for this agreement.
*
* PENDING:
* If an agreement is in PENDING state it means that an ADDBARequest frame was sent to
* recipient in order to setup the block ack and the originator is waiting for the relative
* ADDBAResponse frame.
*
* ESTABLISHED:
* The block ack is active and all packets relative to this agreement are transmitted
* with ack policy set to block ack.
*
* INACTIVE:
* In our implementation, block ack tear-down happens only if an inactivity timeout occurs
* so we could have an active block ack but a number of packets that doesn't reach the value of
* m_blockAckThreshold (see ns3::BlockAckManager). In these conditions the agreement becomes
* INACTIVE until that the number of packets reaches the value of m_blockAckThreshold again.
*
* UNSUCCESSFUL (not used for now):
* The agreement's state becomes UNSUCCESSFUL if:
*
* - its previous state was PENDING and an ADDBAResponse frame wasn't received from
* recipient station within an interval of time defined by m_bAckSetupTimeout attribute
* in ns3::WifiMac.
* - an ADDBAResponse frame is received from recipient and the Status Code field is set
* to failure.
*
* In both cases for station addressed by BlockAckAgreement::m_peer and for
* TID BlockAckAgreement::m_tid block ack mechanism won't be used.
*/
enum State
{
PENDING,
ESTABLISHED,
INACTIVE,
UNSUCCESSFUL
};
void SetState (enum State state);
/**
* Check if the current state of this agreement is PENDING.
*
* \return true if the current state of this agreement is PENDING,
* false otherwise
*/
bool IsPending (void) const;
/**
* Check if the current state of this agreement is ESTABLISHED.
*
* \return true if the current state of this agreement is ESTABLISHED,
* false otherwise
*/
bool IsEstablished (void) const;
/**
* Check if the current state of this agreement is INACTIVE.
*
* \return true if the current state of this agreement is INACTIVE,
* false otherwise
*/
bool IsInactive (void) const;
/**
* Check if the current state of this agreement is UNSUCCESSFUL.
*
* \return true if the current state of this agreement is UNSUCCESSFUL,
* false otherwise
*/
bool IsUnsuccessful (void) const;
/**
* Notifies a packet's transmission with ack policy Block Ack.
*
* \param nextSeqNumber
*/
void NotifyMpduTransmission (uint16_t nextSeqNumber);
/**
* Returns true if all packets for which a block ack was negotiated have been transmitted so
* a block ack request is needed in order to acknowledge them.
*
* \return true if all packets for which a block ack was negotiated have been transmitted,
* false otherwise
*/
bool IsBlockAckRequestNeeded (void) const;
void CompleteExchange (void);
private:
enum State m_state;
uint16_t m_sentMpdus;
bool m_needBlockAckReq;
//+++++++++
EventId m_OriginatorInactivityEvent;
};
} //namespace ns3
#endif /* ORIGINATOR_BLOCK_ACK_AGREEMENT_H */
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