An implementation of TCP HighSpeed. More...

#include "tcp-highspeed.h"

Inheritance diagram for ns3::TcpHighSpeed:

Collaboration diagram for ns3::TcpHighSpeed:

Public Member Functions
	TcpHighSpeed (void)
	Create an unbound tcp socket. More...

	TcpHighSpeed (const TcpHighSpeed &sock)
	Copy constructor. More...

virtual	~TcpHighSpeed (void)

virtual Ptr< TcpCongestionOps >	Fork ()
	Copy the congestion control algorithm across socket. More...

virtual 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 slow start threshold following HighSpeed principles. More...

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

	TcpNewReno (const TcpNewReno &sock)

	~TcpNewReno ()

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)

virtual	~TcpCongestionOps ()

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
	Implement the GetInstanceTypeId method defined in ObjectBase. 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...

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

	SimpleRefCount (const SimpleRefCount &o)
	Copy constructor. More...

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

SimpleRefCount &	operator= (const SimpleRefCount &o)
	Assignment. 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 uint32_t	TableLookupA (uint32_t w)
	Lookup table for the coefficent a (from RFC 3649) More...

static double	TableLookupB (uint32_t w)
	Lookup table for the coefficent b (from RFC 3649) More...

Static Public Member Functions inherited from ns3::TcpNewReno
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::SimpleRefCount< Object, ObjectBase, ObjectDeleter >
static void	Cleanup (void)
	Noop. 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)
	Congestion avoidance of TcpHighSpeed. More...

Protected Member Functions inherited from ns3::TcpNewReno
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...

Private Attributes
uint32_t	m_ackCnt
	Number of received ACK, corrected with the coefficent a. More...

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

Detailed Description

An implementation of TCP HighSpeed.

Introspection did not find any typical Config paths.

TCP HighSpeed is designed for high-capacity channels or, in general, for TCP connections with large congestion windows. Conceptually, with respect to the standard TCP, HighSpeed makes the cWnd grow faster during the probing phases and accelerates the cWnd recovery from losses. This behavior is executed only when the window grows beyond a certain threshold, which allows TCP Highspeed to be friendly with standard TCP in environments with heavy congestion, without introducing new dangers of congestion collapse. At the core of TCP HighSpeed there are two functions, a(w) and b(w), which respectively specify the cWnd growth addendum and the cWnd reduction factor when given an actual cWnd value w.

More information: http://dl.acm.org/citation.cfm?id=2756518

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 47 of file tcp-highspeed.h.

Constructor & Destructor Documentation

ns3::TcpHighSpeed::TcpHighSpeed ( void )

Create an unbound tcp socket.

Definition at line 40 of file tcp-highspeed.cc.

References NS_LOG_FUNCTION.

ns3::TcpHighSpeed::TcpHighSpeed ( const TcpHighSpeed & sock )

Copy constructor.

Parameters

sock	the object to copy

Definition at line 47 of file tcp-highspeed.cc.

References NS_LOG_FUNCTION.

ns3::TcpHighSpeed::~TcpHighSpeed ( void )

virtual

Definition at line 54 of file tcp-highspeed.cc.

References NS_LOG_FUNCTION.

Member Function Documentation

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

protectedvirtual

Congestion avoidance of TcpHighSpeed.

As implementation choice, we increment cWnd only by MSS, when the right number of ACK has been received. At this point, the important question is: what is the "right number of ACK" ?

As you can recall from RFC, Highspeed works this way:

          w = w + a(w)/w

Let's start when a(w) is 1 (so it is classical NewReno). The formula then is the classical text-book version for NewReno:

          w = w + 1 / w

So, for each segment acked, we increase the window by the quantity 1/w. Or, instead of adding the 1/w quantity for each segment acked, we can track the number of segments acked (m_ackCnt) and increment by 1 MSS when m_ackCnt reaches w.

When a(w) > 1, it means that each segment acked has a different "weight". For instance, when it is equal to 2, we need to increase the window by the quantity 2/w. But, this means that one segment acked is equivalent (from the point of view of incrementing cWnd) to two segments acked in NewReno (1/w + 1/w). That a coefficent is, in other word, the weight of each segment acked. More weight, less ACK are necessary to increment cWnd, which is exactly the Highspeed principle.

Parameters

tcb	internal congestion state
segmentsAcked	count of segments acked

Reimplemented from ns3::TcpNewReno.

Definition at line 98 of file tcp-highspeed.cc.

References m_ackCnt, NS_LOG_FUNCTION, NS_LOG_INFO, and TableLookupA().

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

virtual

Copy the congestion control algorithm across socket.

Returns: a pointer of the copied object

Reimplemented from ns3::TcpNewReno.

Definition at line 60 of file tcp-highspeed.cc.

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

virtual

Get the name of the congestion control algorithm.

Returns: A string identifying the name

Reimplemented from ns3::TcpNewReno.

Definition at line 126 of file tcp-highspeed.cc.

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

virtual

Get slow start threshold following HighSpeed principles.

Parameters

tcb	internal congestion state
bytesInFlight	Bytes in flight

Returns: the slow start threshold value

Reimplemented from ns3::TcpNewReno.

Definition at line 140 of file tcp-highspeed.cc.

References NS_LOG_DEBUG, NS_LOG_FUNCTION, and TableLookupB().

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TypeId ns3::TcpHighSpeed::GetTypeId ( void )

static

Get the type ID.

Returns: the object TypeId

Definition at line 30 of file tcp-highspeed.cc.

References ns3::TypeId::SetParent().

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uint32_t ns3::TcpHighSpeed::TableLookupA ( uint32_t w )

static

Lookup table for the coefficent a (from RFC 3649)

Parameters

w	Window value (in packets)

Returns: the coefficent a

Definition at line 157 of file tcp-highspeed.cc.

Referenced by CongestionAvoidance(), and ns3::TcpHighSpeedIncrementTest::DoRun().

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double ns3::TcpHighSpeed::TableLookupB ( uint32_t w )

static

Lookup table for the coefficent b (from RFC 3649)

Parameters

w	Window value (in packets)

Returns: the coefficent b

Definition at line 458 of file tcp-highspeed.cc.

Referenced by ns3::TcpHighSpeedDecrementTest::DoRun(), and GetSsThresh().

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Member Data Documentation

uint32_t ns3::TcpHighSpeed::m_ackCnt

private

Number of received ACK, corrected with the coefficent a.

Definition at line 97 of file tcp-highspeed.h.

Referenced by CongestionAvoidance().

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

src/internet/model/tcp-highspeed.h
src/internet/model/tcp-highspeed.cc

Public Member Functions

Static Public Member Functions

Protected Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation