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wifi: Fix computation of max A-MSDU size

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This commit is contained in:
Stefano Avallone
2022-11-09 12:29:45 +01:00
committed by Stefano Avallone
parent d2dbd6678f
commit fe8533bc8c
1 changed files with 46 additions and 12 deletions
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58
src/wifi/model/msdu-aggregator.cc
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@@ -178,9 +178,23 @@ MsduAggregator::GetMaxAmsduSize(Mac48Address recipient,
NS_ASSERT(stationManager);
// Retrieve the Capabilities elements advertised by the recipient
Ptr<const VhtCapabilities> vhtCapabilities =
stationManager->GetStationVhtCapabilities(recipient);
Ptr<const HtCapabilities> htCapabilities = stationManager->GetStationHtCapabilities(recipient);
auto ehtCapabilities = stationManager->GetStationEhtCapabilities(recipient);
auto vhtCapabilities = stationManager->GetStationVhtCapabilities(recipient);
auto htCapabilities = stationManager->GetStationHtCapabilities(recipient);
// Determine the maximum MPDU size, which is used to indirectly constrain the maximum
// A-MSDU size in some cases (see below). The maximum MPDU size is advertised
// in the EHT Capabilities element, for the 2.4 GHz band, or in the VHT Capabilities
// element, otherwise.
uint16_t maxMpduSize = 0;
if (ehtCapabilities && m_mac->GetWifiPhy(m_linkId)->GetPhyBand() == WIFI_PHY_BAND_2_4GHZ)
{
maxMpduSize = ehtCapabilities->GetMaxMpduLength();
}
else if (vhtCapabilities && m_mac->GetWifiPhy(m_linkId)->GetPhyBand() != WIFI_PHY_BAND_2_4GHZ)
{
maxMpduSize = vhtCapabilities->GetMaxMpduLength();
}
if (!htCapabilities)
{
@@ -195,29 +209,49 @@ MsduAggregator::GetMaxAmsduSize(Mac48Address recipient,
// Determine the constraint imposed by the recipient based on the PPDU
// format used to transmit the A-MSDU
if (modulation >= WIFI_MOD_CLASS_VHT)
if (modulation >= WIFI_MOD_CLASS_EHT)
{
// the maximum A-MSDU size is indirectly constrained by the maximum MPDU size
// supported by the recipient (see Table 9-34 of 802.11be D2.0)
NS_ABORT_MSG_IF(maxMpduSize == 0, "Max MPDU size not advertised");
maxAmsduSize = std::min(maxAmsduSize, static_cast<uint16_t>(maxMpduSize - 56));
}
else if (modulation == WIFI_MOD_CLASS_HE)
{
// for a non-EHT STA operating in the 2.4 GHz band, the maximum A-MSDU size is
// advertised in the HT Capabilities element. Otherwise, the maximum A-MSDU size is
// indirectly constrained by the maximum MPDU size supported by the recipient
// (see Table 9-34 of 802.11be D2.0)
if (m_mac->GetWifiPhy(m_linkId)->GetStandard() < WIFI_STANDARD_80211be &&
m_mac->GetWifiPhy(m_linkId)->GetPhyBand() == WIFI_PHY_BAND_2_4GHZ)
{
maxAmsduSize = std::min(maxAmsduSize, htCapabilities->GetMaxAmsduLength());
}
else
{
NS_ABORT_MSG_IF(maxMpduSize == 0, "Max MPDU size not advertised");
maxAmsduSize = std::min(maxAmsduSize, static_cast<uint16_t>(maxMpduSize - 56));
}
}
else if (modulation == WIFI_MOD_CLASS_VHT)
{
// the maximum A-MSDU size is indirectly constrained by the maximum MPDU
// size supported by the recipient and advertised in the VHT Capabilities
// element (see Table 9-19 of 802.11-2016 as amended by 802.11ax)
NS_ABORT_MSG_IF(!vhtCapabilities, "VHT Capabilities element not received");
maxAmsduSize =
std::min(maxAmsduSize, static_cast<uint16_t>(vhtCapabilities->GetMaxMpduLength() - 56));
// element (see Table 9-25 of 802.11-2020)
NS_ABORT_MSG_IF(maxMpduSize == 0, "Max MPDU size not advertised");
maxAmsduSize = std::min(maxAmsduSize, static_cast<uint16_t>(maxMpduSize - 56));
}
else if (modulation == WIFI_MOD_CLASS_HT)
else if (modulation >= WIFI_MOD_CLASS_HT)
{
// the maximum A-MSDU size is constrained by the maximum A-MSDU size
// supported by the recipient and advertised in the HT Capabilities
// element (see Table 9-19 of 802.11-2016)
maxAmsduSize = std::min(maxAmsduSize, htCapabilities->GetMaxAmsduLength());
}
else // non-HT PPDU
{
// the maximum A-MSDU size is indirectly constrained by the maximum PSDU size
// supported by the recipient (see Table 9-19 of 802.11-2016)
maxAmsduSize = std::min(maxAmsduSize, static_cast<uint16_t>(3839));
}