Cobalt packet queue disc. More...

#include "cobalt-queue-disc.h"

Inheritance diagram for ns3::CobaltQueueDisc:

Collaboration diagram for ns3::CobaltQueueDisc:

Public Member Functions
	CobaltQueueDisc ()
	CobaltQueueDisc Constructor. More...

virtual	~CobaltQueueDisc ()
	Destructor. More...

int64_t	AssignStreams (int64_t stream)
	Assign a fixed random variable stream number to the random variables used by this model. More...

int64_t	GetDropNext (void) const
	Get the time for next packet drop while in the dropping state. More...

Time	GetInterval (void) const
	Get the interval. More...

double	GetPdrop () const
	Get the drop probability of Blue. More...

Time	GetTarget (void) const
	Get the target queue delay. More...

int64_t	Time2CoDel (Time t) const
	Return the unsigned 32-bit integer representation of the input Time object. More...

Public Member Functions inherited from ns3::QueueDisc
	QueueDisc (const QueueDisc &)=delete

	QueueDisc (QueueDiscSizePolicy policy, QueueSizeUnit unit)
	Constructor. More...

	QueueDisc (QueueDiscSizePolicy policy=QueueDiscSizePolicy::SINGLE_INTERNAL_QUEUE)
	Constructor. More...

virtual	~QueueDisc ()

void	AddInternalQueue (Ptr< InternalQueue > queue)
	Add an internal queue to the tail of the list of queues. More...

void	AddPacketFilter (Ptr< PacketFilter > filter)
	Add a packet filter to the tail of the list of filters used to classify packets. More...

void	AddQueueDiscClass (Ptr< QueueDiscClass > qdClass)
	Add a queue disc class to the tail of the list of classes. More...

int32_t	Classify (Ptr< QueueDiscItem > item)
	Classify a packet by calling the packet filters, one at a time, until either a filter able to classify the packet is found or all the filters have been processed. More...

Ptr< QueueDiscItem >	Dequeue (void)
	Extract from the queue disc the packet that has been dequeued by calling Peek, if any, or call the private DoDequeue method (which must be implemented by derived classes) to dequeue a packet, otherwise. More...

bool	Enqueue (Ptr< QueueDiscItem > item)
	Pass a packet to store to the queue discipline. More...

QueueSize	GetCurrentSize (void)
	Get the current size of the queue disc in bytes, if operating in bytes mode, or packets, otherwise. More...

Ptr< InternalQueue >	GetInternalQueue (std::size_t i) const
	Get the i-th internal queue. More...

QueueSize	GetMaxSize (void) const
	Get the maximum size of the queue disc. More...

uint32_t	GetNBytes (void) const
	Get the amount of bytes stored by the queue disc. More...

Ptr< NetDeviceQueueInterface >	GetNetDeviceQueueInterface (void) const

std::size_t	GetNInternalQueues (void) const
	Get the number of internal queues. More...

std::size_t	GetNPacketFilters (void) const
	Get the number of packet filters. More...

uint32_t	GetNPackets (void) const
	Get the number of packets stored by the queue disc. More...

std::size_t	GetNQueueDiscClasses (void) const
	Get the number of queue disc classes. More...

Ptr< PacketFilter >	GetPacketFilter (std::size_t i) const
	Get the i-th packet filter. More...

Ptr< QueueDiscClass >	GetQueueDiscClass (std::size_t i) const
	Get the i-th queue disc class. More...

virtual uint32_t	GetQuota (void) const
	Get the maximum number of dequeue operations following a packet enqueue. More...

SendCallback	GetSendCallback (void) const

const Stats &	GetStats (void)
	Retrieve all the collected statistics. More...

virtual WakeMode	GetWakeMode (void) const
	When setting up the wake callbacks on the netdevice queues, it is necessary to determine which queue disc (the root queue disc or one of its children) should be activated when the netdevice wakes one of its transmission queues. More...

QueueDisc &	operator= (const QueueDisc &)=delete

Ptr< const QueueDiscItem >	Peek (void)
	Get a copy of the next packet the queue discipline will extract. More...

void	Run (void)
	Modelled after the Linux function __qdisc_run (net/sched/sch_generic.c) Dequeues multiple packets, until a quota is exceeded or sending a packet to the device failed. More...

bool	SetMaxSize (QueueSize size)
	Set the maximum size of the queue disc. More...

void	SetNetDeviceQueueInterface (Ptr< NetDeviceQueueInterface > ndqi)

virtual void	SetQuota (const uint32_t quota)
	Set the maximum number of dequeue operations following a packet enqueue. More...

void	SetSendCallback (SendCallback func)

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

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

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

template<typename T >
Ptr< T >	GetObject (void) const
	Get a pointer to the requested aggregated Object. 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[[maybe_unused]])
	Copy constructor. More...

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

SimpleRefCount &	operator= ([[maybe_unused]] 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::QueueDisc
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...

Static Public Attributes
static constexpr const char *	CE_THRESHOLD_EXCEEDED_MARK = "CE threshold exceeded mark"
	Sojourn time above CE threshold. More...

static constexpr const char *	FORCED_MARK = "forcedMark"
	forced marks by Codel on ECN-enabled More...

static constexpr const char *	OVERLIMIT_DROP = "Overlimit drop"
	Overlimit dropped packet. More...

static constexpr const char *	TARGET_EXCEEDED_DROP = "Target exceeded drop"
	Sojourn time above target. More...

Static Public Attributes inherited from ns3::QueueDisc
static constexpr const char *	CHILD_QUEUE_DISC_DROP = "(Dropped by child queue disc) "
	Packet dropped by a child queue disc. More...

static constexpr const char *	CHILD_QUEUE_DISC_MARK = "(Marked by child queue disc) "
	Packet marked by a child queue disc. More...

static constexpr const char *	INTERNAL_QUEUE_DROP = "Dropped by internal queue"
	Packet dropped by an internal queue. More...

Protected Member Functions
virtual void	DoDispose (void)
	Dispose of the object. More...

Protected Member Functions inherited from ns3::QueueDisc
void	DoInitialize (void)
	Check whether the configuration is correct and initialize parameters. More...

void	DropAfterDequeue (Ptr< const QueueDiscItem > item, const char *reason)
	Perform the actions required when the queue disc is notified of a packet dropped after dequeue. More...

void	DropBeforeEnqueue (Ptr< const QueueDiscItem > item, const char *reason)
	Perform the actions required when the queue disc is notified of a packet dropped before enqueue. More...

bool	Mark (Ptr< QueueDiscItem > item, const char *reason)
	Marks the given packet and, if successful, updates the counters associated with the given reason. More...

Protected Member Functions inherited from ns3::Object
	Object (const Object &o)
	Copy an Object. 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 Member Functions
void	CacheInit (void)
	There is a big difference in timing between the accurate values placed in the cache and the approximations given by a single Newton step for small count values, particularly when stepping from count 1 to 2 or vice versa. More...

virtual bool	CheckConfig (void)
	Check whether the current configuration is correct. More...

void	CobaltQueueEmpty (int64_t now)
	Called when the queue becomes empty to alter the drop probabilities of Blue. More...

void	CobaltQueueFull (int64_t now)
	Called when the queue becomes full to alter the drop probabilities of Blue. More...

bool	CobaltShouldDrop (Ptr< QueueDiscItem > item, int64_t now)
	Called to decide whether the current packet should be dropped based on decisions taken by Blue and Codel working parallely. More...

bool	CoDelTimeAfter (int64_t a, int64_t b)
	Check if CoDel time a is successive to b. More...

bool	CoDelTimeAfterEq (int64_t a, int64_t b)
	Check if CoDel time a is successive or equal to b. More...

int64_t	ControlLaw (int64_t t)
	Determine the time for next drop CoDel control law is t + m_interval/sqrt(m_count). More...

virtual Ptr< QueueDiscItem >	DoDequeue (void)
	This function actually extracts a packet from the queue disc. More...

virtual bool	DoEnqueue (Ptr< QueueDiscItem > item)
	This function actually enqueues a packet into the queue disc. More...

virtual Ptr< const QueueDiscItem >	DoPeek (void)
	Return a copy of the next packet the queue disc will extract. More...

virtual void	InitializeParams (void)
	Initialize the queue parameters. More...

void	InvSqrt (void)
	Updates the inverse square root. More...

void	NewtonStep (void)
	Calculate the reciprocal square root of m_count by using Newton's method http://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Iterative_methods_for_reciprocal_square_roots m_recInvSqrt (new) = (m_recInvSqrt (old) / 2) * (3 - m_count * m_recInvSqrt^2) More...

Private Attributes
Time	m_blueThreshold
	Threshold to enable blue enhancement. More...

Time	m_ceThreshold
	Threshold above which to CE mark. More...

TracedValue< uint32_t >	m_count
	Number of packets dropped since entering drop state. More...

double	m_decrement
	decrement value for marking probability More...

TracedValue< int64_t >	m_dropNext
	Time to drop next packet. More...

TracedValue< bool >	m_dropping
	True if in dropping state. More...

double	m_increment
	increment value for marking probability More...

Time	m_interval
	sliding minimum time window width More...

uint32_t	m_lastUpdateTimeBlue
	Blue's last update time for drop probability. More...

double	m_pDrop
	Drop Probability. More...

uint32_t	m_recInvSqrt
	Reciprocal inverse square root. More...

uint32_t	m_recInvSqrtCache [REC_INV_SQRT_CACHE] = {0}
	Cache to maintain some initial values of InvSqrt. More...

Stats	m_stats
	Cobalt statistics. More...

Time	m_target
	target queue delay More...

bool	m_useEcn
	True if ECN is used (packets are marked instead of being dropped) More...

bool	m_useL4s
	True if L4S is used (ECT1 packets are marked at CE threshold) More...

Ptr< UniformRandomVariable >	m_uv
	Rng stream. More...

Additional Inherited Members
Public Types inherited from ns3::QueueDisc
typedef Queue< QueueDiscItem >	InternalQueue
	Internal queues store QueueDiscItem objects. More...

typedef std::function< void(Ptr< QueueDiscItem >)>	SendCallback
	Callback invoked to send a packet to the receiving object when Run is called. More...

enum	WakeMode { WAKE_ROOT = 0x00 , WAKE_CHILD = 0x01 }
	Used to determine whether the queue disc itself or its children must be activated when a netdevice wakes a transmission queue. More...

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

Cobalt packet queue disc.

Introspection did not find any typical Config paths.

Cobalt uses CoDel and BLUE algorithms in parallel, in order to obtain the best features of each. CoDel is excellent on flows which respond to congestion signals in a TCP-like way. BLUE is far more effective on unresponsive flows.

Attributes

MaxSize: The maximum number of packets/bytes accepted by this queue disc.
- Set with class: QueueSizeValue
- Underlying type: QueueSize
- Initial value: 1500000B
- Flags: construct write read
Interval: The Cobalt algorithm interval
- Set with class: ns3::TimeValue
- Underlying type: Time +9.22337e+18ns:+9.22337e+18ns
- Initial value: 100ms
- Flags: construct write read
Target: The Cobalt algorithm target queue delay
- Set with class: ns3::TimeValue
- Underlying type: Time +9.22337e+18ns:+9.22337e+18ns
- Initial value: 5ms
- Flags: construct write read
UseEcn: True to use ECN (packets are marked instead of being dropped)
- Set with class: BooleanValue
- Underlying type: bool
- Initial value: false
- Flags: construct write read
Pdrop: Marking Probability
- Set with class: ns3::DoubleValue
- Underlying type: double -1.79769e+308:1.79769e+308
- Initial value: 0
- Flags: construct write read
Increment: Pdrop increment value
- Set with class: ns3::DoubleValue
- Underlying type: double -1.79769e+308:1.79769e+308
- Initial value: 0.00390625
- Flags: construct write read
Decrement: Pdrop decrement Value
- Set with class: ns3::DoubleValue
- Underlying type: double -1.79769e+308:1.79769e+308
- Initial value: 0.000244141
- Flags: construct write read
CeThreshold: The CoDel CE threshold for marking packets
- Set with class: ns3::TimeValue
- Underlying type: Time +9.22337e+18ns:+9.22337e+18ns
- Initial value: +9.22337e+18ns
- Flags: construct write read
UseL4s: True to use L4S (only ECT1 packets are marked at CE threshold)
- Set with class: BooleanValue
- Underlying type: bool
- Initial value: false
- Flags: construct write read
BlueThreshold: The Threshold after which Blue is enabled
- Set with class: ns3::TimeValue
- Underlying type: Time +9.22337e+18ns:+9.22337e+18ns
- Initial value: +4e+08ns
- Flags: construct write read

Attributes defined in parent class ns3::QueueDisc

Quota: The maximum number of packets dequeued in a qdisc run
- Set with class: ns3::UintegerValue
- Underlying type: uint32_t 0:4294967295
- Initial value: 64
- Flags: construct write read
InternalQueueList: The list of internal queues.
- Set with class: ns3::ObjectPtrContainerValue
- Underlying type: ns3::Ptr< ns3::Queue<QueueDiscItem>>
- Flags: read
PacketFilterList: The list of packet filters.
- Set with class: ns3::ObjectPtrContainerValue
- Underlying type: ns3::Ptr< ns3::PacketFilter>
- Flags: read
QueueDiscClassList: The list of queue disc classes.
- Set with class: ns3::ObjectPtrContainerValue
- Underlying type: ns3::Ptr< ns3::QueueDiscClass>
- Flags: read

TraceSources

Count: Cobalt count
Callback signature: ns3::TracedValueCallback::Uint32
DropState: Dropping state
Callback signature: ns3::TracedValueCallback::Bool
DropNext: Time until next packet drop
Callback signature: ns3::TracedValueCallback::Uint32

TraceSources defined in parent class ns3::QueueDisc

Enqueue: Enqueue a packet in the queue disc
Callback signature: ns3::QueueDiscItem::TracedCallback
Dequeue: Dequeue a packet from the queue disc
Callback signature: ns3::QueueDiscItem::TracedCallback
Requeue: Requeue a packet in the queue disc
Callback signature: ns3::QueueDiscItem::TracedCallback
Drop: Drop a packet stored in the queue disc
Callback signature: ns3::QueueDiscItem::TracedCallback
DropBeforeEnqueue: Drop a packet before enqueue
Callback signature: ns3::QueueDiscItem::TracedCallback
DropAfterDequeue: Drop a packet after dequeue
Callback signature: ns3::QueueDiscItem::TracedCallback
Mark: Mark a packet stored in the queue disc
Callback signature: ns3::QueueDiscItem::TracedCallback
PacketsInQueue: Number of packets currently stored in the queue disc
Callback signature: ns3::TracedValueCallback::Uint32
BytesInQueue: Number of bytes currently stored in the queue disc
Callback signature: ns3::TracedValueCallback::Uint32
SojournTime: Sojourn time of the last packet dequeued from the queue disc
Callback signature: ns3::Time::TracedCallback

Size of this type is 1776 bytes (on a 64-bit architecture).

Definition at line 59 of file cobalt-queue-disc.h.

Constructor & Destructor Documentation

◆ CobaltQueueDisc()

ns3::CobaltQueueDisc::CobaltQueueDisc ( )

CobaltQueueDisc Constructor.

Create a Cobalt queue disc

Definition at line 144 of file cobalt-queue-disc.cc.

References InitializeParams(), m_uv, and NS_LOG_FUNCTION.

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◆ ~CobaltQueueDisc()

ns3::CobaltQueueDisc::~CobaltQueueDisc ( )

virtual

Destructor.

Destructor

Definition at line 157 of file cobalt-queue-disc.cc.

References NS_LOG_FUNCTION.

Member Function Documentation

◆ AssignStreams()

int64_t ns3::CobaltQueueDisc::AssignStreams ( int64_t stream )

Assign a fixed random variable stream number to the random variables used by this model.

Return the number of streams (possibly zero) that have been assigned.

Parameters

stream first stream index to use

Returns: the number of stream indices assigned by this model

Definition at line 163 of file cobalt-queue-disc.cc.

References m_uv, NS_LOG_FUNCTION, and ns3::RandomVariableStream::SetStream().

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◆ CacheInit()

void ns3::CobaltQueueDisc::CacheInit ( void )

private

There is a big difference in timing between the accurate values placed in the cache and the approximations given by a single Newton step for small count values, particularly when stepping from count 1 to 2 or vice versa.

Above 16, a single Newton step gives sufficient accuracy in either direction, given the precision stored.

The magnitude of the error when stepping up to count 2 is such as to give the value that should have been produced at count 4.

Definition at line 234 of file cobalt-queue-disc.cc.

References m_count, m_recInvSqrt, m_recInvSqrtCache, NewtonStep(), and REC_INV_SQRT_CACHE.

Referenced by InitializeParams().

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◆ CheckConfig()

bool ns3::CobaltQueueDisc::CheckConfig ( void )

privatevirtual

Check whether the current configuration is correct.

Default objects (such as internal queues) might be created by this method to ensure the configuration is correct. This method is automatically called at simulation initialization time, and it is called before the InitializeParams () method. It is appropriate to promote parameter initialization to this method if it aids in checking for correct configuration.

See also: QueueDisc::InitializeParams

Returns: true if the configuration is correct, false otherwise

Implements ns3::QueueDisc.

Definition at line 296 of file cobalt-queue-disc.cc.

References ns3::QueueDisc::AddInternalQueue(), ns3::CreateObjectWithAttributes(), ns3::QueueDisc::GetMaxSize(), ns3::QueueDisc::GetNInternalQueues(), ns3::QueueDisc::GetNPacketFilters(), ns3::QueueDisc::GetNQueueDiscClasses(), NS_LOG_ERROR, and NS_LOG_FUNCTION.

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◆ CobaltQueueEmpty()

void ns3::CobaltQueueDisc::CobaltQueueEmpty ( int64_t now )

private

Called when the queue becomes empty to alter the drop probabilities of Blue.

Parameters

now	time in CoDel time units (microseconds)

Definition at line 413 of file cobalt-queue-disc.cc.

References CoDelTimeAfter(), CoDelTimeAfterEq(), ControlLaw(), InvSqrt(), m_count, m_decrement, m_dropNext, m_dropping, m_lastUpdateTimeBlue, m_pDrop, m_target, max, NS_LOG_FUNCTION, and Time2CoDel().

Referenced by DoDequeue().

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◆ CobaltQueueFull()

void ns3::CobaltQueueDisc::CobaltQueueFull ( int64_t now )

private

Called when the queue becomes full to alter the drop probabilities of Blue.

Parameters

now	time in CoDel time units (microseconds)

Definition at line 394 of file cobalt-queue-disc.cc.

References CoDelTimeAfter(), m_count, m_dropNext, m_dropping, m_increment, m_lastUpdateTimeBlue, m_pDrop, m_target, min, NS_LOG_FUNCTION, NS_LOG_LOGIC, and Time2CoDel().

Referenced by DoEnqueue().

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◆ CobaltShouldDrop()

bool ns3::CobaltQueueDisc::CobaltShouldDrop	(	Ptr< QueueDiscItem >	item,
		int64_t	now
	)

private

Called to decide whether the current packet should be dropped based on decisions taken by Blue and Codel working parallely.

Returns: true if the packet should be dropped, false otherwise

Parameters

item	current packet
now	time in CoDel time units (microseconds)

Definition at line 432 of file cobalt-queue-disc.cc.

References ns3::Time::As(), CE_THRESHOLD_EXCEEDED_MARK, CoDelTimeAfter(), ControlLaw(), FORCED_MARK, ns3::Time::GetSeconds(), ns3::UniformRandomVariable::GetValue(), InvSqrt(), ns3::QueueItem::IP_DSFIELD, m_blueThreshold, m_ceThreshold, m_count, m_dropNext, m_dropping, m_increment, m_interval, m_lastUpdateTimeBlue, m_pDrop, m_target, m_useEcn, m_useL4s, m_uv, ns3::QueueDisc::Mark(), max, min, ns3::Simulator::Now(), NS_LOG_DEBUG, NS_LOG_FUNCTION, NS_LOG_INFO, NS_LOG_LOGIC, ns3::Time::S, and Time2CoDel().

Referenced by DoDequeue().

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◆ CoDelTimeAfter()

bool ns3::CobaltQueueDisc::CoDelTimeAfter	(	int64_t	a,
		int64_t	b
	)

private

Check if CoDel time a is successive to b.

Parameters

a	left operand
b	right operand

Returns: true if a is greater than b

Definition at line 185 of file cobalt-queue-disc.cc.

Referenced by CobaltQueueEmpty(), CobaltQueueFull(), and CobaltShouldDrop().

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◆ CoDelTimeAfterEq()

bool ns3::CobaltQueueDisc::CoDelTimeAfterEq	(	int64_t	a,
		int64_t	b
	)

private

Check if CoDel time a is successive or equal to b.

Parameters

a	left operand
b	right operand

Returns: true if a is greater than or equal to b

Definition at line 191 of file cobalt-queue-disc.cc.

Referenced by CobaltQueueEmpty().

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◆ ControlLaw()

int64_t ns3::CobaltQueueDisc::ControlLaw ( int64_t t )

private

Determine the time for next drop CoDel control law is t + m_interval/sqrt(m_count).

Here, we use m_recInvSqrt calculated by Newton's method in NewtonStep() to avoid both sqrt() and divide operations

Parameters

t	Current next drop time

Returns: The new next drop time:

Definition at line 263 of file cobalt-queue-disc.cc.

References m_interval, m_recInvSqrt, NS_LOG_FUNCTION, ns3::ReciprocalDivide(), and Time2CoDel().

Referenced by CobaltQueueEmpty(), and CobaltShouldDrop().

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◆ DoDequeue()

Ptr< QueueDiscItem > ns3::CobaltQueueDisc::DoDequeue ( void )

privatevirtual

This function actually extracts a packet from the queue disc.

Returns: 0 if the operation was not successful; the item otherwise.

Implements ns3::QueueDisc.

Definition at line 354 of file cobalt-queue-disc.cc.

References CobaltQueueEmpty(), CobaltShouldDrop(), ns3::CoDelGetTime(), ns3::QueueDisc::DropAfterDequeue(), ns3::QueueDisc::GetInternalQueue(), ns3::QueueDisc::GetNBytes(), ns3::QueueDisc::GetNPackets(), m_dropping, NS_LOG_FUNCTION, NS_LOG_LOGIC, and TARGET_EXCEEDED_DROP.

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◆ DoDispose()

void ns3::CobaltQueueDisc::DoDispose ( void )

protectedvirtual

Dispose of the object.

Reimplemented from ns3::QueueDisc.

Definition at line 270 of file cobalt-queue-disc.cc.

References ns3::QueueDisc::DoDispose(), m_uv, and NS_LOG_FUNCTION.

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◆ DoEnqueue()

bool ns3::CobaltQueueDisc::DoEnqueue ( Ptr< QueueDiscItem > item )

privatevirtual

This function actually enqueues a packet into the queue disc.

Parameters

item	item to enqueue

Returns: True if the operation was successful; false otherwise

Implements ns3::QueueDisc.

Definition at line 328 of file cobalt-queue-disc.cc.

References CobaltQueueFull(), ns3::CoDelGetTime(), ns3::QueueDisc::DropBeforeEnqueue(), ns3::QueueDisc::GetCurrentSize(), ns3::QueueDisc::GetInternalQueue(), ns3::QueueDisc::GetMaxSize(), ns3::QueueDisc::GetNBytes(), ns3::QueueDisc::GetNPackets(), NS_LOG_FUNCTION, NS_LOG_LOGIC, and OVERLIMIT_DROP.

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◆ DoPeek()

Ptr< const QueueDiscItem > ns3::CobaltQueueDisc::DoPeek ( void )

privatevirtual

Return a copy of the next packet the queue disc will extract.

The implementation of this method is based on the qdisc_peek_dequeued function of the Linux kernel, which dequeues a packet and retains it in the queue disc as a requeued packet. The packet is not traced as requeued, nor is the total count of requeued packets increased. The packet is still considered to be part of the queue disc and the dequeue trace is fired when Dequeue is called and the packet is actually extracted from the queue disc.

This approach is especially recommended for queue discs for which it is not obvious what is the next packet that will be dequeued (e.g., queue discs having multiple internal queues or child queue discs or queue discs that drop packets after dequeue). Subclasses can however provide their own implementation of this method that overrides the default one.

Returns: 0 if the operation was not successful; the packet otherwise.

Reimplemented from ns3::QueueDisc.

Definition at line 278 of file cobalt-queue-disc.cc.

References ns3::QueueDisc::GetInternalQueue(), ns3::QueueDisc::GetNBytes(), ns3::QueueDisc::GetNPackets(), NS_LOG_FUNCTION, and NS_LOG_LOGIC.

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◆ GetDropNext()

int64_t ns3::CobaltQueueDisc::GetDropNext ( void ) const

Get the time for next packet drop while in the dropping state.

Returns: The time (in microseconds) for next packet drop

Definition at line 215 of file cobalt-queue-disc.cc.

References m_dropNext.

◆ GetInterval()

Time ns3::CobaltQueueDisc::GetInterval ( void ) const

Get the interval.

Returns: The interval

Definition at line 209 of file cobalt-queue-disc.cc.

References m_interval.

◆ GetPdrop()

double ns3::CobaltQueueDisc::GetPdrop ( ) const

Get the drop probability of Blue.

Returns: The current value of Blue's drop probability

Definition at line 152 of file cobalt-queue-disc.cc.

References m_pDrop.

◆ GetTarget()

Time ns3::CobaltQueueDisc::GetTarget ( void ) const

Get the target queue delay.

Returns: The target queue delay

Definition at line 203 of file cobalt-queue-disc.cc.

References m_target.

◆ GetTypeId()

TypeId ns3::CobaltQueueDisc::GetTypeId ( void )

static

Get the type ID.

Returns: the object TypeId

Definition at line 45 of file cobalt-queue-disc.cc.

References ns3::BYTES, DEFAULT_COBALT_LIMIT, ns3::QueueDisc::GetMaxSize(), m_blueThreshold, m_ceThreshold, m_count, m_decrement, m_dropNext, m_dropping, m_increment, m_interval, m_pDrop, m_target, m_useEcn, m_useL4s, ns3::MakeBooleanAccessor(), ns3::MakeBooleanChecker(), ns3::MakeDoubleAccessor(), ns3::MakeQueueSizeAccessor(), ns3::MakeQueueSizeChecker(), ns3::MakeTimeAccessor(), ns3::MakeTimeChecker(), ns3::MakeTraceSourceAccessor(), ns3::Time::Max(), ns3::MilliSeconds(), ns3::QueueDisc::SetMaxSize(), and ns3::TypeId::SetParent().

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◆ InitializeParams()

void ns3::CobaltQueueDisc::InitializeParams ( void )

privatevirtual

Initialize the queue parameters.

Implements ns3::QueueDisc.

Definition at line 171 of file cobalt-queue-disc.cc.

References CacheInit(), m_count, m_dropNext, m_dropping, m_lastUpdateTimeBlue, m_recInvSqrt, m_recInvSqrtCache, and NS_LOG_FUNCTION.

Referenced by CobaltQueueDisc().

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◆ InvSqrt()

void ns3::CobaltQueueDisc::InvSqrt ( void )

private

Updates the inverse square root.

Definition at line 250 of file cobalt-queue-disc.cc.

References m_count, m_recInvSqrt, m_recInvSqrtCache, NewtonStep(), and REC_INV_SQRT_CACHE.

Referenced by CobaltQueueEmpty(), and CobaltShouldDrop().

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◆ NewtonStep()

void ns3::CobaltQueueDisc::NewtonStep ( void )

private

Calculate the reciprocal square root of m_count by using Newton's method http://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Iterative_methods_for_reciprocal_square_roots m_recInvSqrt (new) = (m_recInvSqrt (old) / 2) * (3 - m_count * m_recInvSqrt^2)

Definition at line 221 of file cobalt-queue-disc.cc.

References m_count, m_recInvSqrt, and NS_LOG_FUNCTION.

Referenced by CacheInit(), and InvSqrt().

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◆ Time2CoDel()

int64_t ns3::CobaltQueueDisc::Time2CoDel ( Time t ) const

Return the unsigned 32-bit integer representation of the input Time object.

Units are microseconds

Parameters

t	the input Time Object

Returns: the unsigned 32-bit integer representation

Definition at line 197 of file cobalt-queue-disc.cc.

References ns3::Time::GetNanoSeconds().

Referenced by CobaltQueueEmpty(), CobaltQueueFull(), CobaltShouldDrop(), and ControlLaw().

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Member Data Documentation

◆ CE_THRESHOLD_EXCEEDED_MARK

constexpr const char* ns3::CobaltQueueDisc::CE_THRESHOLD_EXCEEDED_MARK = "CE threshold exceeded mark"

staticconstexpr

Sojourn time above CE threshold.

Definition at line 106 of file cobalt-queue-disc.h.

Referenced by CobaltShouldDrop().

◆ FORCED_MARK

constexpr const char* ns3::CobaltQueueDisc::FORCED_MARK = "forcedMark"

staticconstexpr

forced marks by Codel on ECN-enabled

Definition at line 105 of file cobalt-queue-disc.h.

Referenced by CobaltShouldDrop().

◆ m_blueThreshold

Time ns3::CobaltQueueDisc::m_blueThreshold

private

Threshold to enable blue enhancement.

Definition at line 241 of file cobalt-queue-disc.h.

Referenced by CobaltShouldDrop(), and GetTypeId().

◆ m_ceThreshold

Time ns3::CobaltQueueDisc::m_ceThreshold

private

Threshold above which to CE mark.

Definition at line 239 of file cobalt-queue-disc.h.

Referenced by CobaltShouldDrop(), and GetTypeId().

◆ m_count

TracedValue<uint32_t> ns3::CobaltQueueDisc::m_count

private

Number of packets dropped since entering drop state.

Definition at line 229 of file cobalt-queue-disc.h.

Referenced by CacheInit(), CobaltQueueEmpty(), CobaltQueueFull(), CobaltShouldDrop(), GetTypeId(), InitializeParams(), InvSqrt(), and NewtonStep().

◆ m_decrement

double ns3::CobaltQueueDisc::m_decrement

private

decrement value for marking probability

Definition at line 250 of file cobalt-queue-disc.h.

Referenced by CobaltQueueEmpty(), and GetTypeId().

◆ m_dropNext

TracedValue<int64_t> ns3::CobaltQueueDisc::m_dropNext

private

Time to drop next packet.

Definition at line 230 of file cobalt-queue-disc.h.

Referenced by CobaltQueueEmpty(), CobaltQueueFull(), CobaltShouldDrop(), GetDropNext(), GetTypeId(), and InitializeParams().

◆ m_dropping

TracedValue<bool> ns3::CobaltQueueDisc::m_dropping

private

True if in dropping state.

Definition at line 231 of file cobalt-queue-disc.h.

Referenced by CobaltQueueEmpty(), CobaltQueueFull(), CobaltShouldDrop(), DoDequeue(), GetTypeId(), and InitializeParams().

◆ m_increment

double ns3::CobaltQueueDisc::m_increment

private

increment value for marking probability

Definition at line 249 of file cobalt-queue-disc.h.

Referenced by CobaltQueueFull(), CobaltShouldDrop(), and GetTypeId().

◆ m_interval

Time ns3::CobaltQueueDisc::m_interval

private

sliding minimum time window width

Definition at line 236 of file cobalt-queue-disc.h.

Referenced by CobaltShouldDrop(), ControlLaw(), GetInterval(), and GetTypeId().

◆ m_lastUpdateTimeBlue

uint32_t ns3::CobaltQueueDisc::m_lastUpdateTimeBlue

private

Blue's last update time for drop probability.

Definition at line 246 of file cobalt-queue-disc.h.

Referenced by CobaltQueueEmpty(), CobaltQueueFull(), CobaltShouldDrop(), and InitializeParams().

◆ m_pDrop

double ns3::CobaltQueueDisc::m_pDrop

private

Drop Probability.

Definition at line 251 of file cobalt-queue-disc.h.

Referenced by CobaltQueueEmpty(), CobaltQueueFull(), CobaltShouldDrop(), GetPdrop(), and GetTypeId().

◆ m_recInvSqrt

uint32_t ns3::CobaltQueueDisc::m_recInvSqrt

private

Reciprocal inverse square root.

Definition at line 232 of file cobalt-queue-disc.h.

Referenced by CacheInit(), ControlLaw(), InitializeParams(), InvSqrt(), and NewtonStep().

◆ m_recInvSqrtCache

uint32_t ns3::CobaltQueueDisc::m_recInvSqrtCache[REC_INV_SQRT_CACHE] = {0}

private

Cache to maintain some initial values of InvSqrt.

Definition at line 233 of file cobalt-queue-disc.h.

Referenced by CacheInit(), InitializeParams(), and InvSqrt().

◆ m_stats

Stats ns3::CobaltQueueDisc::m_stats

private

Cobalt statistics.

Definition at line 225 of file cobalt-queue-disc.h.

◆ m_target

Time ns3::CobaltQueueDisc::m_target

private

target queue delay

Definition at line 237 of file cobalt-queue-disc.h.

Referenced by CobaltQueueEmpty(), CobaltQueueFull(), CobaltShouldDrop(), GetTarget(), and GetTypeId().

◆ m_useEcn

bool ns3::CobaltQueueDisc::m_useEcn

private

True if ECN is used (packets are marked instead of being dropped)

Definition at line 238 of file cobalt-queue-disc.h.

Referenced by CobaltShouldDrop(), and GetTypeId().

◆ m_useL4s

bool ns3::CobaltQueueDisc::m_useL4s

private

True if L4S is used (ECT1 packets are marked at CE threshold)

Definition at line 240 of file cobalt-queue-disc.h.

Referenced by CobaltShouldDrop(), and GetTypeId().

◆ m_uv

Ptr<UniformRandomVariable> ns3::CobaltQueueDisc::m_uv

private

Rng stream.

Definition at line 245 of file cobalt-queue-disc.h.

Referenced by CobaltQueueDisc(), AssignStreams(), CobaltShouldDrop(), and DoDispose().

◆ OVERLIMIT_DROP

constexpr const char* ns3::CobaltQueueDisc::OVERLIMIT_DROP = "Overlimit drop"

staticconstexpr

Overlimit dropped packet.

Definition at line 104 of file cobalt-queue-disc.h.

Referenced by DoEnqueue().

◆ TARGET_EXCEEDED_DROP

constexpr const char* ns3::CobaltQueueDisc::TARGET_EXCEEDED_DROP = "Target exceeded drop"

staticconstexpr

Sojourn time above target.

Definition at line 103 of file cobalt-queue-disc.h.

Referenced by DoDequeue().

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

src/traffic-control/model/cobalt-queue-disc.h
src/traffic-control/model/cobalt-queue-disc.cc

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Attributes

Attributes defined in parent class ns3::QueueDisc

TraceSources

TraceSources defined in parent class ns3::QueueDisc

Constructor & Destructor Documentation

◆ CobaltQueueDisc()

◆ ~CobaltQueueDisc()

Member Function Documentation

◆ AssignStreams()

◆ CacheInit()

◆ CheckConfig()

◆ CobaltQueueEmpty()

◆ CobaltQueueFull()

◆ CobaltShouldDrop()

◆ CoDelTimeAfter()

◆ CoDelTimeAfterEq()

◆ ControlLaw()

◆ DoDequeue()

◆ DoDispose()

◆ DoEnqueue()

◆ DoPeek()

◆ GetDropNext()

◆ GetInterval()

◆ GetPdrop()

◆ GetTarget()

◆ GetTypeId()

◆ InitializeParams()

◆ InvSqrt()

◆ NewtonStep()

◆ Time2CoDel()

Member Data Documentation

◆ CE_THRESHOLD_EXCEEDED_MARK

◆ FORCED_MARK

◆ m_blueThreshold

◆ m_ceThreshold

◆ m_count

◆ m_decrement

◆ m_dropNext

◆ m_dropping

◆ m_increment

◆ m_interval

◆ m_lastUpdateTimeBlue

◆ m_pDrop

◆ m_recInvSqrt

◆ m_recInvSqrtCache

◆ m_stats

◆ m_target

◆ m_useEcn

◆ m_useL4s

◆ m_uv

◆ OVERLIMIT_DROP

◆ TARGET_EXCEEDED_DROP