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wifi: BA manager retransmits packets under BA agreement

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This commit is contained in:
Stefano Avallone
2019-06-23 19:46:55 +02:00
parent ecf384fb2b
commit 561ed7cf95
2 changed files with 38 additions and 3 deletions
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19
src/wifi/model/block-ack-manager.cc
View File

@@ -195,9 +195,22 @@ BlockAckManager::UpdateAgreement (const MgtAddBaResponseHeader *respHdr, Mac48Ad
agreement.SetBufferSize (respHdr->GetBufferSize () + 1);
agreement.SetTimeout (respHdr->GetTimeout ());
agreement.SetAmsduSupport (respHdr->IsAmsduSupported ());
// update the starting sequence number because some frames may have been sent
// under Normal Ack policy after the transmission of the ADDBA Request frame
agreement.SetStartingSequence (m_txMiddle->GetNextSeqNumberByTidAndAddress (tid, recipient));
// When the Add BA Response is received, there may be a packet transmitted
// under the normal ack policy that needs to be retransmitted. If so, such
// packet is placed in the retransmit queue. If this is the case, the starting
// sequence number is the sequence number of such packet. Otherwise, it is
// the sequence number that will be assigned to the next packet to be transmitted.
uint16_t startSeq;
WifiMacQueue::ConstIterator mpduIt = m_retryPackets->PeekByTidAndAddress (tid, recipient);
if (mpduIt != m_retryPackets->end ())
{
startSeq = (*mpduIt)->GetHeader ().GetSequenceNumber ();
}
else
{
startSeq = m_txMiddle->GetNextSeqNumberByTidAndAddress (tid, recipient);
}
agreement.SetStartingSequence (startSeq);
agreement.InitTxWindow ();
if (respHdr->IsImmediateBlockAck ())
{

22
src/wifi/model/qos-txop.cc
View File

@@ -474,6 +474,12 @@ QosTxop::NotifyAccessGranted (void)
NS_LOG_DEBUG ("the lifetime of current packet expired");
m_currentPacket = 0;
}
// If the current packet is a QoS Data frame, then there must be no block ack agreement
// established with the receiver for the TID of the packet. Indeed, retransmission
// of MPDUs sent under a block ack agreement is handled through the retransmit queue.
NS_ASSERT (m_currentPacket == 0 || !m_currentHdr.IsQosData ()
|| !GetBaAgreementEstablished (m_currentHdr.GetAddr1 (), m_currentHdr.GetQosTid ()));
if (m_currentPacket == 0)
{
if (m_baManager->HasBar (m_currentBar))
@@ -1412,6 +1418,22 @@ QosTxop::GotAddBaResponse (const MgtAddBaResponseHeader *respHdr, Mac48Address r
if (respHdr->GetStatusCode ().IsSuccess ())
{
NS_LOG_DEBUG ("block ack agreement established with " << recipient);
// Even though a (destination, TID) pair is "blocked" (i.e., no more packets
// are sent) when an Add BA Request is sent to the destination,
// the current packet may still be non-null when the Add BA Response is received.
// In fact, if the Add BA Request timer expires, the (destination, TID) pair is
// "unblocked" and packets to the destination are sent again (under normal
// ack policy). Thus, there may be a packet needing to be retransmitted
// when the Add BA Response is received. If this is the case, let the Block
// Ack manager handle its retransmission.
if (m_currentPacket != 0 && m_currentHdr.IsQosData ()
&& m_currentHdr.GetAddr1 () == recipient && m_currentHdr.GetQosTid () == tid)
{
Ptr<WifiMacQueueItem> mpdu = Create<WifiMacQueueItem> (m_currentPacket, m_currentHdr,
m_currentPacketTimestamp);
m_baManager->GetRetransmitQueue ()->Enqueue (mpdu);
m_currentPacket = 0;
}
m_baManager->UpdateAgreement (respHdr, recipient);
}
else