keep track of the state needed for a single DCF function.Multiple instances of a DcfState can be registered in a single DcfManager to implement 802.11e-style relative QoS. DcfState::SetAifsn and DcfState::SetCwBounds allow the user to control the relative QoS differentiation. More...

#include <dcf-manager.h>

Inheritance diagram for ns3::DcfState:

Public Member Functions
uint32_t	GetAifsn (void) const

uint32_t	GetCw (void) const

uint32_t	GetCwMax (void) const

uint32_t	GetCwMin (void) const

bool	IsAccessRequested (void) const

void	ResetCw (void)

void	SetAifsn (uint32_t aifsn)

void	SetCwMax (uint32_t maxCw)

void	SetCwMin (uint32_t minCw)

void	StartBackoffNow (uint32_t nSlots)

void	UpdateFailedCw (void)

Private Member Functions
virtual void	DoNotifyAccessGranted (void)=0

virtual void	DoNotifyChannelSensing ()=0

virtual void	DoNotifyChannelSwitching (Time duration, uint16_t toChannel)=0

virtual void	DoNotifyCollision (void)=0

virtual void	DoNotifyInternalCollision (void)=0

uint32_t	GetBackoffSlots (void) const

Time	GetBackoffStart (void) const

void	NotifyAccessGranted (void)

void	NotifyAccessRequested (void)

void	NotifyChannelSensing (void)

void	NotifyChannelSwitching (Time duration, uint16_t toChannel)

void	NotifyCollision (void)

void	NotifyInternalCollision (void)

void	UpdateBackoffSlotsNow (uint32_t nSlots, Time backoffUpdateBound)

Private Attributes
bool	m_accessRequested

uint32_t	m_aifsn

uint32_t	m_backoffSlots

Time	m_backoffStart

uint32_t	m_cw

uint32_t	m_cwMax

uint32_t	m_cwMin

Friends
class	DcfManager

Detailed Description

keep track of the state needed for a single DCF function.

Multiple instances of a DcfState can be registered in a single DcfManager to implement 802.11e-style relative QoS. DcfState::SetAifsn and DcfState::SetCwBounds allow the user to control the relative QoS differentiation.

Definition at line 46 of file dcf-manager.h.

Member Function Documentation

virtual void ns3::DcfState::DoNotifyAccessGranted ( void )

privatepure virtual

Called by DcfManager to notify a DcfState subclass that access to the medium is granted and can start immediately.

Implemented in ns3::DcaTxop::Dcf, ns3::EdcaTxopN::Dcf, and ns3::DcfStateTest.

virtual void ns3::DcfState::DoNotifyChannelSwitching	(	Time	duration,
		uint16_t	toChannel
	)

privatepure virtual

Called by DcfManager to notify a DcfState subclass that a channel switching occured.

The subclass is expected to flush the queue of packets.

Implemented in ns3::DcaTxop::Dcf, and ns3::EdcaTxopN::Dcf.

virtual void ns3::DcfState::DoNotifyCollision ( void )

privatepure virtual

Called by DcfManager to notify a DcfState subclass that a normal collision occured, that is, that the medium was busy when access was requested.

The subclass is expected to start a new backoff by calling DcfState::StartBackoffNow and DcfManager::RequestAccess is access is still needed.

Implemented in ns3::DcaTxop::Dcf, ns3::EdcaTxopN::Dcf, and ns3::DcfStateTest.

virtual void ns3::DcfState::DoNotifyInternalCollision ( void )

privatepure virtual

Called by DcfManager to notify a DcfState subclass that an 'internal' collision occured, that is, that the backoff timer of a higher priority DcfState expired at the same time and that access was granted to this higher priority DcfState.

The subclass is expected to start a new backoff by calling DcfState::StartBackoffNow and DcfManager::RequestAccess is access is still needed.

Implemented in ns3::DcaTxop::Dcf, ns3::EdcaTxopN::Dcf, and ns3::DcfStateTest.

uint32_t ns3::DcfState::GetCw ( void ) const

Returns: the current value of the CW variable. The initial value is minCW.

Definition at line 118 of file dcf-manager.cc.

Referenced by ns3::DcaTxop::DoInitialize(), and ns3::EdcaTxopN::DoInitialize().

bool ns3::DcfState::IsAccessRequested ( void ) const

Returns: true if access has been requested for this DcfState and has not been granted already, false otherwise.

Definition at line 133 of file dcf-manager.cc.

Referenced by ns3::DcfManager::DoGrantAccess(), ns3::DcfManager::DoRestartAccessTimeoutIfNeeded(), ns3::DcfManager::RequestAccess(), and ns3::DcaTxop::RestartAccessIfNeeded().

void ns3::DcfState::ResetCw ( void )

Update the value of the CW variable to take into account a transmission success or a transmission abort (stop transmission of a packet after the maximum number of retransmissions has been reached). By default, this resets the CW variable to minCW.

Definition at line 90 of file dcf-manager.cc.

Referenced by ns3::DcaTxop::DoInitialize(), ns3::EdcaTxopN::DoInitialize(), and ns3::DcfManager::NotifySwitchingStartNow().

void ns3::DcfState::SetAifsn ( uint32_t aifsn )

Parameters

aifsn the number of slots which make up an AIFS for a specific DCF. a DIFS corresponds to an AIFSN = 2.

Calling this method after DcfManager::Add has been called is not recommended.

Definition at line 57 of file dcf-manager.cc.

void ns3::DcfState::StartBackoffNow ( uint32_t nSlots )

Parameters

nSlots the number of slots of the backoff.

Start a backoff by initializing the backoff counter to the number of slots specified.

Definition at line 109 of file dcf-manager.cc.

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

Referenced by ns3::DcaTxop::DoInitialize(), and ns3::EdcaTxopN::DoInitialize().

void ns3::DcfState::UpdateFailedCw ( void )

Update the value of the CW variable to take into account a transmission failure. By default, this triggers a doubling of CW (capped by maxCW).

Definition at line 95 of file dcf-manager.cc.

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 Member Functions

Private Attributes

Friends

Detailed Description

Member Function Documentation