A Discrete-Event Network Simulator
API
ns3::TcpNewReno Class Reference

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. More...
 
 ~TcpNewReno ()
 
virtual Ptr< TcpCongestionOpsFork ()
 Copy the congestion control algorithm across sockets. More...
 
std::string GetName () const
 Get the name of the congestion control algorithm. More...
 
virtual uint32_t GetSsThresh (Ptr< const TcpSocketState > tcb, uint32_t bytesInFlight)
 Get the slow start threshold after a loss event. More...
 
virtual void IncreaseWindow (Ptr< TcpSocketState > tcb, uint32_t segmentsAcked)
 Try to increase the cWnd following the NewReno specification. More...
 
- Public Member Functions inherited from ns3::TcpCongestionOps
 TcpCongestionOps ()
 
 TcpCongestionOps (const TcpCongestionOps &other)
 Copy constructor. More...
 
virtual ~TcpCongestionOps ()
 
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. More...
 
virtual void CongestionStateSet (Ptr< TcpSocketState > tcb, const TcpSocketState::TcpCongState_t newState)
 Trigger events/calculations specific to a congestion state. More...
 
virtual void CwndEvent (Ptr< TcpSocketState > tcb, const TcpSocketState::TcpCAEvent_t event)
 Trigger events/calculations on occurrence of congestion window event. More...
 
virtual bool HasCongControl () const
 Returns true when Congestion Control Algorithm implements CongControl. More...
 
virtual void PktsAcked (Ptr< TcpSocketState > tcb, uint32_t segmentsAcked, const Time &rtt)
 Timing information on received ACK. More...
 
- Public Member Functions inherited from ns3::Object
 Object ()
 Constructor. More...
 
virtual ~Object ()
 Destructor. More...
 
void AggregateObject (Ptr< Object > other)
 Aggregate two Objects together. More...
 
void Dispose (void)
 Dispose of this Object. More...
 
AggregateIterator GetAggregateIterator (void) const
 Get an iterator to the Objects aggregated to this one. More...
 
virtual TypeId GetInstanceTypeId (void) const
 Get the most derived TypeId for this Object. More...
 
template<typename T >
Ptr< T > GetObject (void) const
 Get a pointer to the requested aggregated Object. More...
 
template<typename T >
Ptr< T > GetObject (TypeId tid) const
 Get a pointer to the requested aggregated Object by TypeId. More...
 
void Initialize (void)
 Invoke DoInitialize on all Objects aggregated to this one. More...
 
bool IsInitialized (void) const
 Check if the object has been initialized. More...
 
- Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter >
 SimpleRefCount ()
 Default constructor. More...
 
 SimpleRefCount (const SimpleRefCount &o)
 Copy constructor. More...
 
uint32_t GetReferenceCount (void) const
 Get the reference count of the object. More...
 
SimpleRefCountoperator= (const SimpleRefCount &o)
 Assignment operator. More...
 
void Ref (void) const
 Increment the reference count. More...
 
void Unref (void) const
 Decrement the reference count. More...
 
- Public Member Functions inherited from ns3::ObjectBase
virtual ~ObjectBase ()
 Virtual destructor. More...
 
void GetAttribute (std::string name, AttributeValue &value) const
 Get the value of an attribute, raising fatal errors if unsuccessful. More...
 
bool GetAttributeFailSafe (std::string name, AttributeValue &value) const
 Get the value of an attribute without raising erros. More...
 
void SetAttribute (std::string name, const AttributeValue &value)
 Set a single attribute, raising fatal errors if unsuccessful. More...
 
bool SetAttributeFailSafe (std::string name, const AttributeValue &value)
 Set a single attribute without raising errors. More...
 
bool TraceConnect (std::string name, std::string context, const CallbackBase &cb)
 Connect a TraceSource to a Callback with a context. More...
 
bool TraceConnectWithoutContext (std::string name, const CallbackBase &cb)
 Connect a TraceSource to a Callback without a context. More...
 
bool TraceDisconnect (std::string name, std::string context, const CallbackBase &cb)
 Disconnect from a TraceSource a Callback previously connected with a context. More...
 
bool TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb)
 Disconnect from a TraceSource a Callback previously connected without a context. More...
 

Static Public Member Functions

static TypeId GetTypeId (void)
 Get the type ID. More...
 
- Static Public Member Functions inherited from ns3::TcpCongestionOps
static TypeId GetTypeId (void)
 Get the type ID. More...
 
- Static Public Member Functions inherited from ns3::Object
static TypeId GetTypeId (void)
 Register this type. More...
 
- Static Public Member Functions inherited from ns3::ObjectBase
static TypeId GetTypeId (void)
 Get the type ID. More...
 

Protected Member Functions

virtual void CongestionAvoidance (Ptr< TcpSocketState > tcb, uint32_t segmentsAcked)
 NewReno congestion avoidance. More...
 
virtual uint32_t SlowStart (Ptr< TcpSocketState > tcb, uint32_t segmentsAcked)
 
Tcp NewReno slow start algorithm More...
 
- Protected Member Functions inherited from ns3::Object
 Object (const Object &o)
 Copy an Object. More...
 
virtual void DoDispose (void)
 Destructor implementation. More...
 
virtual void DoInitialize (void)
 Initialize() implementation. More...
 
virtual void NotifyNewAggregate (void)
 Notify all Objects aggregated to this one of a new Object being aggregated. More...
 
- Protected Member Functions inherited from ns3::ObjectBase
void ConstructSelf (const AttributeConstructionList &attributes)
 Complete construction of ObjectBase; invoked by derived classes. More...
 
virtual void NotifyConstructionCompleted (void)
 Notifier called once the ObjectBase is fully constructed. More...
 

Additional Inherited Members

Detailed Description

The NewReno implementation.


Introspection did not find any typical Config paths.

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

See also
IncreaseWindow


No Attributes are defined for this type.
No TraceSources are defined for this type.
Size of this type is 32 bytes (on a 64-bit architecture).

Definition at line 205 of file tcp-congestion-ops.h.

Constructor & Destructor Documentation

◆ TcpNewReno() [1/2]

ns3::TcpNewReno::TcpNewReno ( void  )

Definition at line 109 of file tcp-congestion-ops.cc.

References NS_LOG_FUNCTION.

◆ TcpNewReno() [2/2]

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

Copy constructor.

Parameters
sockobject to copy.

Definition at line 114 of file tcp-congestion-ops.cc.

References NS_LOG_FUNCTION.

◆ ~TcpNewReno()

ns3::TcpNewReno::~TcpNewReno ( void  )

Definition at line 120 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
tcbinternal congestion state
segmentsAckedcount of segments acked

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

Definition at line 191 of file tcp-congestion-ops.cc.

References ns3::TracedValue< T >::Get(), ns3::TcpSocketState::m_cWnd, ns3::TcpSocketState::m_segmentSize, ns3::TcpSocketState::m_ssThresh, max, NS_LOG_FUNCTION, and NS_LOG_INFO.

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

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◆ Fork()

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

Copy the congestion control algorithm across sockets.

Returns
a pointer of the copied object

Implements ns3::TcpCongestionOps.

Reimplemented in ns3::TcpYeah, ns3::TcpIllinois, ns3::TcpVeno, ns3::TcpVegas, ns3::TcpWestwood, ns3::TcpLedbat, ns3::TcpScalable, ns3::TcpHighSpeed, ns3::TcpLp, ns3::TcpHybla, and ns3::TcpHtcp.

Definition at line 255 of file tcp-congestion-ops.cc.

◆ GetName()

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

Get the name of the congestion control algorithm.

Returns
A string identifying the name

Implements ns3::TcpCongestionOps.

Reimplemented in ns3::TcpIllinois, ns3::TcpYeah, ns3::TcpVeno, ns3::TcpLedbat, ns3::TcpVegas, ns3::TcpScalable, ns3::TcpLp, ns3::TcpHybla, ns3::TcpHighSpeed, and ns3::TcpHtcp.

Definition at line 240 of file tcp-congestion-ops.cc.

◆ GetSsThresh()

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

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 implementator 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
tcbinternal congestion state
bytesInFlighttotal bytes in flight
Returns
Slow start threshold

Implements ns3::TcpCongestionOps.

Reimplemented in ns3::TcpYeah, ns3::TcpIllinois, ns3::TcpVeno, ns3::TcpVegas, ns3::TcpWestwood, ns3::TcpScalable, ns3::TcpHighSpeed, and ns3::TcpHtcp.

Definition at line 246 of file tcp-congestion-ops.cc.

References max, and NS_LOG_FUNCTION.

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

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◆ GetTypeId()

TypeId ns3::TcpNewReno::GetTypeId ( void  )
static

Get the type ID.

Returns
the object TypeId

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

References ns3::TypeId::SetParent().

Referenced by ns3::TcpL4Protocol::GetTypeId().

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◆ IncreaseWindow()

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

Try to increase the cWnd following the NewReno specification.

See also
SlowStart
CongestionAvoidance
Parameters
tcbinternal congestion state
segmentsAckedcount of segments acked

Reimplemented from ns3::TcpCongestionOps.

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

Definition at line 215 of file tcp-congestion-ops.cc.

References CongestionAvoidance(), ns3::TcpSocketState::m_cWnd, ns3::TcpSocketState::m_ssThresh, NS_LOG_FUNCTION, and SlowStart().

Referenced by TcpHighSpeedIncrementTest::DoRun(), TcpHyblaIncrementTest::DoRun(), TcpScalableIncrementTest::DoRun(), TcpHtcpIncrementTest::DoRun(), TcpLedbatToNewReno::ExecuteTest(), ns3::TcpVegas::IncreaseWindow(), and ns3::TcpVeno::IncreaseWindow().

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◆ 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
tcbinternal congestion state
segmentsAckedcount of segments acked
Returns
the number of segments not considered for increasing the cWnd

Reimplemented in ns3::TcpHybla.

Definition at line 167 of file tcp-congestion-ops.cc.

References ns3::TcpSocketState::m_cWnd, ns3::TcpSocketState::m_segmentSize, ns3::TcpSocketState::m_ssThresh, NS_LOG_FUNCTION, and NS_LOG_INFO.

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

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