The NewReno implementation. More...

#include "tcp-congestion-ops.h"

Inheritance diagram for ns3::TcpNewReno:

Collaboration diagram for ns3::TcpNewReno:

Public Member Functions
	TcpNewReno ()

	TcpNewReno (const TcpNewReno &sock)
	Copy constructor.

	~TcpNewReno () override

Ptr< TcpCongestionOps >	Fork () override
	Copy the congestion control algorithm across sockets.

std::string	GetName () const override
	Get the name of the congestion control algorithm.

uint32_t	GetSsThresh (Ptr< const TcpSocketState > tcb, uint32_t bytesInFlight) override
	Get the slow start threshold after a loss event.

void	IncreaseWindow (Ptr< TcpSocketState > tcb, uint32_t segmentsAcked) override
	Try to increase the cWnd following the NewReno specification.

Public Member Functions inherited from ns3::TcpCongestionOps
	TcpCongestionOps ()

	TcpCongestionOps (const TcpCongestionOps &other)
	Copy constructor.

	~TcpCongestionOps () override

virtual void	CongControl (Ptr< TcpSocketState > tcb, const TcpRateOps::TcpRateConnection &rc, const TcpRateOps::TcpRateSample &rs)
	Called when packets are delivered to update cwnd and pacing rate.

virtual void	CongestionStateSet (Ptr< TcpSocketState > tcb, const TcpSocketState::TcpCongState_t newState)
	Trigger events/calculations specific to a congestion state.

virtual void	CwndEvent (Ptr< TcpSocketState > tcb, const TcpSocketState::TcpCAEvent_t event)
	Trigger events/calculations on occurrence of congestion window event.

virtual bool	HasCongControl () const
	Returns true when Congestion Control Algorithm implements CongControl.

virtual void	Init (Ptr< TcpSocketState > tcb)
	Set configuration required by congestion control algorithm.

virtual void	PktsAcked (Ptr< TcpSocketState > tcb, uint32_t segmentsAcked, const Time &rtt)
	Timing information on received ACK.

Public Member Functions inherited from ns3::Object
	Object ()
	Constructor.

	~Object () override
	Destructor.

void	AggregateObject (Ptr< Object > other)
	Aggregate two Objects together.

void	Dispose ()
	Dispose of this Object.

AggregateIterator	GetAggregateIterator () const
	Get an iterator to the Objects aggregated to this one.

TypeId	GetInstanceTypeId () const override
	Get the most derived TypeId for this Object.

template<typename T >
Ptr< T >	GetObject () const
	Get a pointer to the requested aggregated Object.

template<>
Ptr< Object >	GetObject () const
	Specialization of () for objects of type ns3::Object.

template<typename T >
Ptr< T >	GetObject (TypeId tid) const
	Get a pointer to the requested aggregated Object by TypeId.

template<>
Ptr< Object >	GetObject (TypeId tid) const
	Specialization of (TypeId tid) for objects of type ns3::Object.

void	Initialize ()
	Invoke DoInitialize on all Objects aggregated to this one.

bool	IsInitialized () const
	Check if the object has been initialized.

void	UnidirectionalAggregateObject (Ptr< Object > other)
	Aggregate an Object to another Object.

Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter >
	SimpleRefCount ()
	Default constructor.

	SimpleRefCount (const SimpleRefCount &o)
	Copy constructor.

uint32_t	GetReferenceCount () const
	Get the reference count of the object.

SimpleRefCount &	operator= (const SimpleRefCount &o)
	Assignment operator.

void	Ref () const
	Increment the reference count.

void	Unref () const
	Decrement the reference count.

Public Member Functions inherited from ns3::ObjectBase
virtual	~ObjectBase ()
	Virtual destructor.

void	GetAttribute (std::string name, AttributeValue &value, bool permissive=false) const
	Get the value of an attribute, raising fatal errors if unsuccessful.

bool	GetAttributeFailSafe (std::string name, AttributeValue &value) const
	Get the value of an attribute without raising errors.

void	SetAttribute (std::string name, const AttributeValue &value)
	Set a single attribute, raising fatal errors if unsuccessful.

bool	SetAttributeFailSafe (std::string name, const AttributeValue &value)
	Set a single attribute without raising errors.

bool	TraceConnect (std::string name, std::string context, const CallbackBase &cb)
	Connect a TraceSource to a Callback with a context.

bool	TraceConnectWithoutContext (std::string name, const CallbackBase &cb)
	Connect a TraceSource to a Callback without a context.

bool	TraceDisconnect (std::string name, std::string context, const CallbackBase &cb)
	Disconnect from a TraceSource a Callback previously connected with a context.

bool	TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb)
	Disconnect from a TraceSource a Callback previously connected without a context.

Static Public Member Functions
static TypeId	GetTypeId ()
	Get the type ID.

Static Public Member Functions inherited from ns3::TcpCongestionOps
static TypeId	GetTypeId ()
	Get the type ID.

Static Public Member Functions inherited from ns3::Object
static TypeId	GetTypeId ()
	Register this type.

Static Public Member Functions inherited from ns3::ObjectBase
static TypeId	GetTypeId ()
	Get the type ID.

Protected Member Functions
virtual void	CongestionAvoidance (Ptr< TcpSocketState > tcb, uint32_t segmentsAcked)
	NewReno congestion avoidance.

virtual uint32_t	SlowStart (Ptr< TcpSocketState > tcb, uint32_t segmentsAcked)
	Tcp NewReno slow start algorithm.

Protected Member Functions inherited from ns3::Object
	Object (const Object &o)
	Copy an Object.

virtual void	DoDispose ()
	Destructor implementation.

virtual void	DoInitialize ()
	Initialize() implementation.

virtual void	NotifyNewAggregate ()
	Notify all Objects aggregated to this one of a new Object being aggregated.

Protected Member Functions inherited from ns3::ObjectBase
void	ConstructSelf (const AttributeConstructionList &attributes)
	Complete construction of ObjectBase; invoked by derived classes.

virtual void	NotifyConstructionCompleted ()
	Notifier called once the ObjectBase is fully constructed.

Additional Inherited Members
Related Symbols inherited from ns3::ObjectBase
static TypeId	GetObjectIid ()
	Ensure the TypeId for ObjectBase gets fully configured to anchor the inheritance tree properly.

Detailed Description

The NewReno implementation.

New Reno introduces partial ACKs inside the well-established Reno algorithm. This and other modifications are described in RFC 6582.

See also: IncreaseWindow

Definition at line 200 of file tcp-congestion-ops.h.

Constructor & Destructor Documentation

◆ TcpNewReno() [1/2]

ns3::TcpNewReno::TcpNewReno ( )

Definition at line 93 of file tcp-congestion-ops.cc.

References NS_LOG_FUNCTION.

◆ TcpNewReno() [2/2]

ns3::TcpNewReno::TcpNewReno ( const TcpNewReno & sock )

Copy constructor.

Parameters

sock	object to copy.

Definition at line 99 of file tcp-congestion-ops.cc.

References NS_LOG_FUNCTION.

◆ ~TcpNewReno()

ns3::TcpNewReno::~TcpNewReno ( )

override

Definition at line 105 of file tcp-congestion-ops.cc.

Member Function Documentation

◆ CongestionAvoidance()

void ns3::TcpNewReno::CongestionAvoidance	(	Ptr< TcpSocketState >	tcb,
		uint32_t	segmentsAcked )

protectedvirtual

NewReno congestion avoidance.

During congestion avoidance, cwnd is incremented by roughly 1 full-sized segment per round-trip time (RTT).

Parameters

tcb	internal congestion state
segmentsAcked	count of segments acked

Reimplemented in ns3::TcpHighSpeed, ns3::TcpHtcp, ns3::TcpHybla, ns3::TcpLedbat, ns3::TcpLp, and ns3::TcpScalable.

Definition at line 177 of file tcp-congestion-ops.cc.

References NS_LOG_FUNCTION, and NS_LOG_INFO.

Referenced by ns3::TcpLedbat::CongestionAvoidance(), ns3::TcpLp::CongestionAvoidance(), IncreaseWindow(), ns3::TcpVeno::IncreaseWindow(), and ns3::TcpYeah::IncreaseWindow().

Here is the caller graph for this function:

◆ Fork()

Ptr< TcpCongestionOps > ns3::TcpNewReno::Fork ( )

overridevirtual

Copy the congestion control algorithm across sockets.

Returns: a pointer of the copied object

Implements ns3::TcpCongestionOps.

Reimplemented in ns3::TcpScalable, ns3::TcpVegas, ns3::TcpVeno, ns3::TcpWestwoodPlus, and ns3::TcpYeah.

Definition at line 241 of file tcp-congestion-ops.cc.

References ns3::Object::CopyObject.

◆ GetName()

std::string ns3::TcpNewReno::GetName ( ) const

overridevirtual

Get the name of the congestion control algorithm.

Returns: A string identifying the name

Implements ns3::TcpCongestionOps.

Reimplemented in ns3::TcpScalable, ns3::TcpVegas, ns3::TcpVeno, and ns3::TcpYeah.

Definition at line 227 of file tcp-congestion-ops.cc.

◆ GetSsThresh()

uint32_t ns3::TcpNewReno::GetSsThresh	(	Ptr< const TcpSocketState >	tcb,
		uint32_t	bytesInFlight )

overridevirtual

Get the slow start threshold after a loss event.

Is guaranteed that the congestion control state (TcpAckState_t) is changed BEFORE the invocation of this method. The implementer should return the slow start threshold (and not change it directly) because, in the future, the TCP implementation may require to instantly recover from a loss event (e.g. when there is a network with an high reordering factor).

Parameters

tcb	internal congestion state
bytesInFlight	total bytes in flight

Returns: Slow start threshold

Implements ns3::TcpCongestionOps.

Reimplemented in ns3::TcpScalable, ns3::TcpVegas, ns3::TcpVeno, ns3::TcpWestwoodPlus, and ns3::TcpYeah.

Definition at line 233 of file tcp-congestion-ops.cc.

References NS_LOG_FUNCTION.

Referenced by ns3::TcpVeno::GetSsThresh().

Here is the caller graph for this function:

◆ GetTypeId()

TypeId ns3::TcpNewReno::GetTypeId ( )

static

Get the type ID.

Returns: the object TypeId

Definition at line 84 of file tcp-congestion-ops.cc.

References ns3::TypeId::SetParent().

Referenced by TcpFastRetrTestSuite::TcpFastRetrTestSuite(), TcpPacingTestSuite::TcpPacingTestSuite(), TcpRenoCongAvoidTestSuite::TcpRenoCongAvoidTestSuite(), TcpRtoTestSuite::TcpRtoTestSuite(), TcpSlowStartTestSuite::TcpSlowStartTestSuite(), and ThreeGppHttpClientServerTestSuite::AddHttpObjectTestCase().

Here is the call graph for this function:

Here is the caller graph for this function:

◆ IncreaseWindow()

void ns3::TcpNewReno::IncreaseWindow	(	Ptr< TcpSocketState >	tcb,
		uint32_t	segmentsAcked )

overridevirtual

Try to increase the cWnd following the NewReno specification.

See also: SlowStart; CongestionAvoidance

Parameters

tcb	internal congestion state
segmentsAcked	count of segments acked

Reimplemented from ns3::TcpCongestionOps.

Reimplemented in ns3::TcpVegas, ns3::TcpVeno, and ns3::TcpYeah.

Definition at line 202 of file tcp-congestion-ops.cc.

References CongestionAvoidance(), NS_LOG_FUNCTION, and SlowStart().

Referenced by ns3::TcpVegas::IncreaseWindow(), and ns3::TcpVeno::IncreaseWindow().

Here is the call graph for this function:

Here is the caller graph for this function:

◆ SlowStart()

uint32_t ns3::TcpNewReno::SlowStart	(	Ptr< TcpSocketState >	tcb,
		uint32_t	segmentsAcked )

protectedvirtual

Tcp NewReno slow start algorithm.

Defined in RFC 5681 as

‍During slow start, a TCP increments cwnd by at most SMSS bytes for each ACK received that cumulatively acknowledges new data. Slow start ends when cwnd exceeds ssthresh (or, optionally, when it reaches it, as noted above) or when congestion is observed. While traditionally TCP implementations have increased cwnd by precisely SMSS bytes upon receipt of an ACK covering new data, we RECOMMEND that TCP implementations increase cwnd, per:
cwnd += min (N, SMSS)                      (2)
where N is the number of previously unacknowledged bytes acknowledged in the incoming ACK.

The ns-3 implementation respect the RFC definition. Linux does something different:

u32 tcp_slow_start(struct tcp_sock *tp, u32 acked)
{
  u32 cwnd = tp->snd_cwnd + acked;
 
  if (cwnd > tp->snd_ssthresh)
    cwnd = tp->snd_ssthresh + 1;
  acked -= cwnd - tp->snd_cwnd;
  tp->snd_cwnd = min(cwnd, tp->snd_cwnd_clamp);
 
  return acked;
}

As stated, we want to avoid the case when a cumulative ACK increases cWnd more than a segment size, but we keep count of how many segments we have ignored, and return them.

Parameters

tcb	internal congestion state
segmentsAcked	count of segments acked

Returns: the number of segments not considered for increasing the cWnd

Reimplemented in ns3::TcpHybla.

Definition at line 152 of file tcp-congestion-ops.cc.

References NS_LOG_FUNCTION, and NS_LOG_INFO.

Referenced by ns3::TcpIllinois::IncreaseWindow(), ns3::TcpLedbat::IncreaseWindow(), IncreaseWindow(), ns3::TcpVegas::IncreaseWindow(), ns3::TcpVeno::IncreaseWindow(), and ns3::TcpYeah::IncreaseWindow().

Here is the caller graph for this function:

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

src/internet/model/tcp-congestion-ops.h
src/internet/model/tcp-congestion-ops.cc

Public Member Functions

Static Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ TcpNewReno() [1/2]

◆ TcpNewReno() [2/2]

◆ ~TcpNewReno()

Member Function Documentation

◆ CongestionAvoidance()

◆ Fork()

◆ GetName()

◆ GetSsThresh()

◆ GetTypeId()

◆ IncreaseWindow()

◆ SlowStart()