Manage a set of ns3::DcfStateHandle a set of independent ns3::DcfState, each of which represents a single DCF within a MAC stack. Each ns3::DcfState has a priority implicitely associated with it (the priority is determined when the ns3::DcfState is added to the DcfManager: the first DcfState to be added gets the highest priority, the second, the second highest priority, and so on.) which is used to handle "internal" collisions. i.e., when two local DcfState are expected to get access to the medium at the same time, the highest priority local DcfState wins access to the medium and the other DcfState suffers a "internal" collision. More...

#include <dcf-manager.h>

Public Member Functions
void	Add (DcfState *dcf)

Time	GetEifsNoDifs () const

void	NotifyAckTimeoutResetNow ()

void	NotifyAckTimeoutStartNow (Time duration)

void	NotifyCtsTimeoutResetNow ()

void	NotifyCtsTimeoutStartNow (Time duration)

void	NotifyMaybeCcaBusyStartNow (Time duration)

void	NotifyNavResetNow (Time duration)

void	NotifyNavStartNow (Time duration)

void	NotifyRxEndErrorNow (void)

void	NotifyRxEndOkNow (void)

void	NotifyRxStartNow (Time duration)

void	NotifySensingStartNow (Time duration)

void	NotifySwitchingStartNow (Time duration, uint16_t toChannel)

void	NotifyTxStartNow (Time duration)

void	RequestAccess (DcfState *state)

void	SetEifsNoDifs (Time eifsNoDifs)

void	SetSifs (Time sifs)

void	SetSlot (Time slotTime)

void	SetupLowListener (Ptr< MacLow > low)

void	SetupPhyListener (Ptr< WifiPhy > phy)

Private Types
typedef std::vector< DcfState * >	States

Private Member Functions
void	AccessTimeout (void)

void	DoGrantAccess (void)

void	DoRestartAccessTimeoutIfNeeded (void)

Time	GetAccessGrantStart (void) const

Time	GetBackoffEndFor (DcfState *state)

Time	GetBackoffStartFor (DcfState *state)

bool	IsBusy (void) const

Time	MostRecent (Time a, Time b) const

Time	MostRecent (Time a, Time b, Time c) const

Time	MostRecent (Time a, Time b, Time c, Time d) const

Time	MostRecent (Time a, Time b, Time c, Time d, Time e, Time f) const

Time	MostRecent (Time a, Time b, Time c, Time d, Time e, Time f, Time g, Time h) const

void	UpdateBackoff (void)

Private Attributes
EventId	m_accessTimeout

Time	m_eifsNoDifs

Time	m_lastAckTimeoutEnd

Time	m_lastBusyDuration

Time	m_lastBusyStart

Time	m_lastCtsTimeoutEnd

Time	m_lastNavDuration

Time	m_lastNavStart

Time	m_lastRxDuration

Time	m_lastRxEnd

bool	m_lastRxReceivedOk

Time	m_lastRxStart

Time	m_lastSensingDuration

Time	m_lastSensingStart

Time	m_lastSwitchingDuration

Time	m_lastSwitchingStart

Time	m_lastTxDuration

Time	m_lastTxStart

LowDcfListener *	m_lowListener

PhyListener *	m_phyListener

bool	m_rxing

Time	m_sifs

bool	m_sleeping

uint32_t	m_slotTimeUs

States	m_states

Detailed Description

Manage a set of ns3::DcfState

Handle a set of independent ns3::DcfState, each of which represents a single DCF within a MAC stack. Each ns3::DcfState has a priority implicitely associated with it (the priority is determined when the ns3::DcfState is added to the DcfManager: the first DcfState to be added gets the highest priority, the second, the second highest priority, and so on.) which is used to handle "internal" collisions. i.e., when two local DcfState are expected to get access to the medium at the same time, the highest priority local DcfState wins access to the medium and the other DcfState suffers a "internal" collision.

Definition at line 175 of file dcf-manager.h.

Member Function Documentation

void ns3::DcfManager::Add ( DcfState * dcf )

Parameters

dcf	a new DcfState.

The DcfManager does not take ownership of this pointer so, the callee must make sure that the DcfState pointer will stay valid as long as the DcfManager is valid. Note that the order in which DcfState objects are added to a DcfManager matters: the first DcfState added has the highest priority, the second DcfState added, has the second highest priority, etc.

Definition at line 338 of file dcf-manager.cc.

References NS_LOG_FUNCTION.

void ns3::DcfManager::DoGrantAccess ( void )

private

This is the first dcf we find with an expired backoff and which needs access to the medium. i.e., it has data to send.

all other dcfs with a lower priority whose backoff has expired and which needed access to the medium must be notified that we did get an internal collision.

Now, we notify all of these changes in one go. It is necessary to perform first the calculations of which states are colliding and then only apply the changes because applying the changes through notification could change the global state of the manager, and, thus, could change the result of the calculations.

Definition at line 443 of file dcf-manager.cc.

References ns3::DcfState::IsAccessRequested(), ns3::Simulator::Now(), and NS_LOG_FUNCTION.

Referenced by RequestAccess().

void ns3::DcfManager::DoRestartAccessTimeoutIfNeeded ( void )

private

Is there a DcfState which needs to access the medium, and, if there is one, how many slots for AIFS+backoff does it require ?

Definition at line 586 of file dcf-manager.cc.

References ns3::EventId::Cancel(), ns3::Simulator::GetDelayLeft(), ns3::Simulator::GetMaximumSimulationTime(), ns3::DcfState::IsAccessRequested(), ns3::EventId::IsExpired(), ns3::EventId::IsRunning(), ns3::Simulator::Now(), NS_LOG_FUNCTION, and ns3::Simulator::Schedule().

Referenced by NotifyNavResetNow(), and RequestAccess().

Time ns3::DcfManager::GetAccessGrantStart ( void ) const

private

Access will never be granted to the medium before the time returned by this method.

Returns: the absolute time at which access could start to be granted

Definition at line 507 of file dcf-manager.cc.

References NS_LOG_FUNCTION, and NS_LOG_INFO.

Time ns3::DcfManager::GetEifsNoDifs ( ) const

Returns: value set previously using SetEifsNoDifs.

Definition at line 331 of file dcf-manager.cc.

References NS_LOG_FUNCTION.

Referenced by ns3::RegularWifiMac::GetEifsNoDifs().

void ns3::DcfManager::NotifyMaybeCcaBusyStartNow ( Time duration )

Parameters

duration expected duration of cca busy period

Notify the DCF that a CCA busy period has just started.

Definition at line 674 of file dcf-manager.cc.

References ns3::Simulator::Now(), and NS_LOG_FUNCTION.

void ns3::DcfManager::NotifyNavResetNow ( Time duration )

Parameters

duration the value of the received NAV.

Called at end of rx

If the nav reset indicates an end-of-nav which is earlier than the previous end-of-nav, the expected end of backoff might be later than previously thought so, we might need to restart a new access timeout.

Definition at line 805 of file dcf-manager.cc.

References DoRestartAccessTimeoutIfNeeded(), ns3::Simulator::Now(), and NS_LOG_FUNCTION.

Referenced by ns3::MeshWifiInterfaceMac::SwitchFrequencyChannel().

void ns3::DcfManager::NotifyNavStartNow ( Time duration )

Parameters

duration the value of the received NAV.

Called at end of rx

Definition at line 822 of file dcf-manager.cc.

References ns3::Simulator::Now(), NS_ASSERT, and NS_LOG_FUNCTION.

void ns3::DcfManager::NotifyRxEndErrorNow ( void )

Notify the DCF that a packet reception was just completed unsuccessfully.

Definition at line 645 of file dcf-manager.cc.

References ns3::Simulator::Now(), and NS_LOG_FUNCTION.

void ns3::DcfManager::NotifyRxEndOkNow ( void )

Notify the DCF that a packet reception was just completed successfully.

Definition at line 636 of file dcf-manager.cc.

References ns3::Simulator::Now(), and NS_LOG_FUNCTION.

void ns3::DcfManager::NotifyRxStartNow ( Time duration )

Parameters

duration expected duration of reception

Notify the DCF that a packet reception started for the expected duration.

Definition at line 626 of file dcf-manager.cc.

References ns3::Simulator::Now(), and NS_LOG_FUNCTION.

void ns3::DcfManager::NotifySwitchingStartNow	(	Time	duration,
		uint16_t	toChannel
	)

Parameters

duration expected duration of channel switching period

Notify the DCF that a channel switching period has just started. During switching state, new packets can be enqueued in DcaTxop/EdcaTxop but they won't access to the medium until the end of the channel switching.

Definition at line 685 of file dcf-manager.cc.

References ns3::EventId::Cancel(), ns3::EventId::IsRunning(), ns3::Simulator::Now(), NS_ASSERT, NS_LOG_FUNCTION, and ns3::DcfState::ResetCw().

void ns3::DcfManager::NotifyTxStartNow ( Time duration )

Parameters

duration expected duration of transmission

Notify the DCF that a packet transmission was just started and is expected to last for the specified duration.

Definition at line 654 of file dcf-manager.cc.

References ns3::Simulator::Now(), NS_ASSERT, and NS_LOG_FUNCTION.

void ns3::DcfManager::RequestAccess ( DcfState * state )

Parameters

state a DcfState

Notify the DcfManager that a specific DcfState needs access to the medium. The DcfManager is then responsible for starting an access timer and, invoking DcfState::DoNotifyAccessGranted when the access is granted if it ever gets granted.

If there is a collision, generate a backoff by notifying the collision to the user.

Definition at line 419 of file dcf-manager.cc.

References DoGrantAccess(), DoRestartAccessTimeoutIfNeeded(), ns3::DcfState::IsAccessRequested(), NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by ns3::DcaTxop::RestartAccessIfNeeded().

void ns3::DcfManager::SetEifsNoDifs ( Time eifsNoDifs )

Parameters

eifsNoDifs the duration of a EIFS minus the duration of DIFS.

It is a bad idea to call this method after RequestAccess or one of the Notify methods has been invoked.

Definition at line 325 of file dcf-manager.cc.

References NS_LOG_FUNCTION.

Referenced by ns3::RegularWifiMac::SetEifsNoDifs().

void ns3::DcfManager::SetSifs ( Time sifs )

Parameters

sifs	the duration of a SIFS.

It is a bad idea to call this method after RequestAccess or one of the Notify methods has been invoked.

Definition at line 319 of file dcf-manager.cc.

References NS_LOG_FUNCTION.

Referenced by ns3::RegularWifiMac::SetSifs().

void ns3::DcfManager::SetSlot ( Time slotTime )

Parameters

slotTime the duration of a slot.

It is a bad idea to call this method after RequestAccess or one of the Notify methods has been invoked.

Definition at line 313 of file dcf-manager.cc.

References ns3::Time::GetMicroSeconds(), and NS_LOG_FUNCTION.

Referenced by ns3::RegularWifiMac::SetSlot().

The documentation for this class was generated from the following files:

src/wifi/model/dcf-manager.h
src/wifi/model/dcf-manager.cc

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Detailed Description

Member Function Documentation