Make sure that when multiple broadcast packets are queued on the same device in a short succession no virtual collision occurs. More...

Inheritance diagram for ns3::Bug555TestCase:

Collaboration diagram for ns3::Bug555TestCase:

Public Member Functions
	Bug555TestCase ()

virtual void	DoRun (void)
	Implementation to actually run this TestCase. More...

Public Member Functions inherited from ns3::TestCase
virtual	~TestCase ()
	Destructor. More...

Private Member Functions
void	NotifyPhyTxBegin (Ptr< const Packet > p)

void	SendOnePacket (Ptr< WifiNetDevice > dev)

Private Attributes
Time	m_firstTransmissionTime

ObjectFactory	m_mac

ObjectFactory	m_manager

unsigned int	m_numSentPackets

ObjectFactory	m_propDelay

Time	m_secondTransmissionTime

Additional Inherited Members
Public Types inherited from ns3::TestCase
enum	TestDuration { QUICK = 1, EXTENSIVE = 2, TAKES_FOREVER = 3 }
	How long the test takes to execute. More...

Protected Member Functions inherited from ns3::TestCase
	TestCase (std::string name)

void	AddTestCase (TestCase *testCase) NS_DEPRECATED
	Add an individual child TestCase case to this TestCase. More...

void	AddTestCase (TestCase *testCase, enum TestDuration duration)
	Add an individual child TestCase to this test suite. More...

std::string	CreateDataDirFilename (std::string filename)

std::string	CreateTempDirFilename (std::string filename)

bool	GetErrorStatus (void) const NS_DEPRECATED

std::string	GetName (void) const

bool	IsStatusFailure (void) const

bool	IsStatusSuccess (void) const

bool	MustAssertOnFailure (void) const

bool	MustContinueOnFailure (void) const

void	ReportTestFailure (std::string cond, std::string actual, std::string limit, std::string message, std::string file, int32_t line)

void	SetDataDir (std::string directory)

Detailed Description

Make sure that when multiple broadcast packets are queued on the same device in a short succession no virtual collision occurs.

The observed behavior is that the first frame will be sent immediately, and the frames are spaced by (backoff + SIFS + AIFS) time intervals (where backoff is a random number of slot sizes up to maximum CW)

The following test case should not generate virtual collision for the second frame. The seed and run numbers were pick such that the second frame gets backoff = 0.

                 frame 1, frame 2
                 arrive                SIFS + AIFS
                 V                    <----------->

time |-----------—|----------------—|----------—|--------—> 0 1s 1.001408s 1.001442s ^ ^ ^ start TX finish TX start TX frame 1 frame 1 frame 2 ^ frame 2 backoff = 0

The buggy behavior was that frame 2 experiences a virtual collision and re-selects the backoff again. As a result, the actual backoff experience by frame 2 is less likely to be 0 since that would require two successions of 0 backoff (one that generates the virtual collision and one after the virtual collision).