A CoDel packet queue disc. More...

#include "codel-queue-disc.h"

Inheritance diagram for ns3::CoDelQueueDisc:

Collaboration diagram for ns3::CoDelQueueDisc:

Public Member Functions
	CoDelQueueDisc ()
	CoDelQueueDisc Constructor.

	~CoDelQueueDisc () override

uint32_t	GetDropNext ()
	Get the time for next packet drop while in the dropping state.

Time	GetInterval ()
	Get the interval.

Time	GetTarget ()
	Get the target queue delay.

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

	QueueDisc (QueueDiscSizePolicy policy, QueueSizeUnit unit)
	Constructor.

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

	~QueueDisc () override

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

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

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

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.

Ptr< QueueDiscItem >	Dequeue ()
	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.

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

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

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

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

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

Ptr< NetDeviceQueueInterface >	GetNetDeviceQueueInterface () const

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

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

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

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

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

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

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

SendCallback	GetSendCallback () const

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

virtual WakeMode	GetWakeMode () 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.

QueueDisc &	operator= (const QueueDisc &)=delete

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

void	Run ()
	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.

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

void	SetNetDeviceQueueInterface (Ptr< NetDeviceQueueInterface > ndqi)

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

void	SetSendCallback (SendCallback func)

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) 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.

virtual TypeId	GetInstanceTypeId () const =0
	Get the most derived TypeId for this Object.

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::QueueDisc
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.

Static Public Attributes
static constexpr const char *	CE_THRESHOLD_EXCEEDED_MARK
	Sojourn time above CE threshold.

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

static constexpr const char *	TARGET_EXCEEDED_DROP
	Sojourn time above target.

static constexpr const char *	TARGET_EXCEEDED_MARK
	Sojourn time above target.

Static Public Attributes inherited from ns3::QueueDisc
static constexpr const char *	CHILD_QUEUE_DISC_DROP
	Packet dropped by a child queue disc.

static constexpr const char *	CHILD_QUEUE_DISC_MARK
	Packet marked by a child queue disc.

static constexpr const char *	INTERNAL_QUEUE_DROP
	Packet dropped by an internal queue.

Private Member Functions
bool	CheckConfig () override
	Check whether the current configuration is correct.

bool	CoDelTimeAfter (uint32_t a, uint32_t b)
	Check if CoDel time a is successive to b.

bool	CoDelTimeAfterEq (uint32_t a, uint32_t b)
	Check if CoDel time a is successive or equal to b.

bool	CoDelTimeBefore (uint32_t a, uint32_t b)
	Check if CoDel time a is preceding b.

bool	CoDelTimeBeforeEq (uint32_t a, uint32_t b)
	Check if CoDel time a is preceding or equal to b.

Ptr< QueueDiscItem >	DoDequeue () override
	Remove a packet from queue based on the current state If we are in dropping state, check if we could leave the dropping state or if we should perform next drop If we are not currently in dropping state, check if we need to enter the state and drop the first packet.

bool	DoEnqueue (Ptr< QueueDiscItem > item) override
	Add a packet to the queue.

void	InitializeParams () override
	Initialize parameters (if any) before the first packet is enqueued.

bool	OkToDrop (Ptr< QueueDiscItem > item, uint32_t now)
	Determine whether a packet is OK to be dropped.

uint32_t	Time2CoDel (Time t)
	Return the unsigned 32-bit integer representation of the input Time object.

Static Private Member Functions
static uint32_t	ControlLaw (uint32_t t, uint32_t interval, uint32_t recInvSqrt)
	Determine the time for next drop CoDel control law is t + m_interval/sqrt(m_count).

static uint16_t	NewtonStep (uint16_t recInvSqrt, uint32_t count)
	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)

Private Attributes
Time	m_ceThreshold
	Threshold above which to CE mark.

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

TracedValue< uint32_t >	m_dropNext
	Time to drop next packet.

TracedValue< bool >	m_dropping
	True if in dropping state.

uint32_t	m_firstAboveTime
	Time to declare sojourn time above target.

Time	m_interval
	100 ms sliding minimum time window width

TracedValue< uint32_t >	m_lastCount
	Last number of packets dropped since entering drop state.

uint32_t	m_minBytes
	Minimum bytes in queue to allow a packet drop.

uint16_t	m_recInvSqrt
	Reciprocal inverse square root.

Time	m_target
	5 ms target queue delay

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

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

Friends
class	::CoDelQueueDiscControlLawTest

class	::CoDelQueueDiscNewtonStepTest

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

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

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...

Protected Member Functions inherited from ns3::QueueDisc
void	DoDispose () override
	Dispose of the object.

void	DoInitialize () override
	Check whether the configuration is correct and initialize parameters.

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.

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.

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

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.

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

Detailed Description

A CoDel packet queue disc.

Introspection did not find any typical Config paths.

Attributes

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: constructwriteread
Interval: The CoDel algorithm interval
- Set with class: ns3::TimeValue
- Underlying type: Time +9.22337e+18ns:+9.22337e+18ns
- Initial value: 100ms
- Flags: constructwriteread
MaxSize: The maximum number of packets/bytes accepted by this queue disc.
- Set with class: ns3::QueueSizeValue
- Underlying type: QueueSize
- Initial value: 1500000B
- Flags: constructwriteread
MinBytes: The CoDel algorithm minbytes parameter.
- Set with class: ns3::UintegerValue
- Underlying type: uint32_t 0:4294967295
- Initial value: 1500
- Flags: constructwriteread
Target: The CoDel algorithm target queue delay
- Set with class: ns3::TimeValue
- Underlying type: Time +9.22337e+18ns:+9.22337e+18ns
- Initial value: 5ms
- Flags: constructwriteread
UseEcn: True to use ECN (packets are marked instead of being dropped)
- Set with class: ns3::BooleanValue
- Underlying type: bool
- Initial value: false
- Flags: constructwriteread
UseL4s: True to use L4S (only ECT1 packets are marked at CE threshold)
- Set with class: ns3::BooleanValue
- Underlying type: bool
- Initial value: false
- Flags: constructwriteread

Attributes defined in parent class ns3::QueueDisc

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
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: constructwriteread

TraceSources

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

TraceSources defined in parent class ns3::QueueDisc

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

Size of this type is 1128 bytes (on a 64-bit architecture).

Definition at line 63 of file codel-queue-disc.h.

Constructor & Destructor Documentation

◆ CoDelQueueDisc()

ns3::CoDelQueueDisc::CoDelQueueDisc ( )

CoDelQueueDisc Constructor.

Creates a CoDel queue

Definition at line 137 of file codel-queue-disc.cc.

References NS_LOG_FUNCTION.

◆ ~CoDelQueueDisc()

ns3::CoDelQueueDisc::~CoDelQueueDisc ( )

override

Definition at line 149 of file codel-queue-disc.cc.

References NS_LOG_FUNCTION.

Member Function Documentation

◆ CheckConfig()

bool ns3::CoDelQueueDisc::CheckConfig ( )

overrideprivatevirtual

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 470 of file codel-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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◆ CoDelTimeAfter()

bool ns3::CoDelQueueDisc::CoDelTimeAfter	(	uint32_t	a,
		uint32_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 440 of file codel-queue-disc.cc.

Referenced by DoDequeue(), and OkToDrop().

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◆ CoDelTimeAfterEq()

bool ns3::CoDelQueueDisc::CoDelTimeAfterEq	(	uint32_t	a,
		uint32_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 446 of file codel-queue-disc.cc.

Referenced by DoDequeue().

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◆ CoDelTimeBefore()

bool ns3::CoDelQueueDisc::CoDelTimeBefore	(	uint32_t	a,
		uint32_t	b
	)

private

Check if CoDel time a is preceding b.

Parameters

a	left operand
b	right operand

Returns: true if a is less than to b

Definition at line 452 of file codel-queue-disc.cc.

Referenced by DoDequeue(), and OkToDrop().

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◆ CoDelTimeBeforeEq()

bool ns3::CoDelQueueDisc::CoDelTimeBeforeEq	(	uint32_t	a,
		uint32_t	b
	)

private

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

Parameters

a	left operand
b	right operand

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

Definition at line 458 of file codel-queue-disc.cc.

◆ ControlLaw()

uint32_t ns3::CoDelQueueDisc::ControlLaw	(	uint32_t	t,
		uint32_t	interval,
		uint32_t	recInvSqrt
	)

staticprivate

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 (in units of CoDel time)
interval	interval (in units of CoDel time)
recInvSqrt	reciprocal value of sqrt (count)

Returns: The new next drop time (in units of CoDel time)

Definition at line 168 of file codel-queue-disc.cc.

References NS_LOG_FUNCTION_NOARGS, REC_INV_SQRT_SHIFT, and ns3::ReciprocalDivide().

Referenced by DoDequeue().

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◆ DoDequeue()

Ptr< QueueDiscItem > ns3::CoDelQueueDisc::DoDequeue ( )

overrideprivatevirtual

Remove a packet from queue based on the current state If we are in dropping state, check if we could leave the dropping state or if we should perform next drop If we are not currently in dropping state, check if we need to enter the state and drop the first packet.

Returns: The packet that is examined

Implements ns3::QueueDisc.

Definition at line 242 of file codel-queue-disc.cc.

References CE_THRESHOLD_EXCEEDED_MARK, ns3::CoDelGetTime(), CoDelTimeAfter(), CoDelTimeAfterEq(), CoDelTimeBefore(), ControlLaw(), ns3::QueueDisc::DropAfterDequeue(), ns3::QueueDisc::GetInternalQueue(), ns3::QueueDisc::GetNBytes(), ns3::QueueDisc::GetNPackets(), ns3::Time::GetSeconds(), ns3::QueueItem::IP_DSFIELD, m_ceThreshold, m_count, m_dropNext, m_dropping, m_interval, m_lastCount, m_recInvSqrt, m_useEcn, m_useL4s, ns3::QueueDisc::Mark(), NewtonStep(), ns3::Simulator::Now(), NS_LOG_DEBUG, NS_LOG_FUNCTION, NS_LOG_LOGIC, OkToDrop(), REC_INV_SQRT_SHIFT, TARGET_EXCEEDED_DROP, TARGET_EXCEEDED_MARK, and Time2CoDel().

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◆ DoEnqueue()

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

overrideprivatevirtual

Add a packet to the queue.

Parameters

item	The item to be added

Returns: True if the packet can be added, False if the packet is dropped due to full queue

Implements ns3::QueueDisc.

Definition at line 175 of file codel-queue-disc.cc.

References 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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◆ GetDropNext()

uint32_t ns3::CoDelQueueDisc::GetDropNext ( )

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

Returns: The time for next packet drop

Definition at line 434 of file codel-queue-disc.cc.

References m_dropNext.

◆ GetInterval()

Time ns3::CoDelQueueDisc::GetInterval ( )

Get the interval.

Returns: The interval

Definition at line 428 of file codel-queue-disc.cc.

References m_interval.

◆ GetTarget()

Time ns3::CoDelQueueDisc::GetTarget ( )

Get the target queue delay.

Returns: The target queue delay

Definition at line 422 of file codel-queue-disc.cc.

References m_target.

◆ GetTypeId()

TypeId ns3::CoDelQueueDisc::GetTypeId ( )

static

Get the type ID.

Returns: the object TypeId

Definition at line 74 of file codel-queue-disc.cc.

References ns3::BYTES, DEFAULT_CODEL_LIMIT, ns3::QueueDisc::GetMaxSize(), m_ceThreshold, m_count, m_dropNext, m_dropping, m_interval, m_lastCount, m_minBytes, m_target, m_useEcn, m_useL4s, ns3::MakeBooleanAccessor(), ns3::MakeBooleanChecker(), ns3::MakeQueueSizeAccessor(), ns3::MakeQueueSizeChecker(), ns3::MakeTimeAccessor(), ns3::MakeTimeChecker(), ns3::MakeTraceSourceAccessor(), ns3::MakeUintegerAccessor(), ns3::Time::Max(), ns3::QueueDisc::SetMaxSize(), and ns3::TypeId::SetParent().

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◆ InitializeParams()

void ns3::CoDelQueueDisc::InitializeParams ( )

overrideprivatevirtual

Initialize parameters (if any) before the first packet is enqueued.

This method is automatically called at simulation initialization time, after the CheckConfig() method has been called.

See also: QueueDisc::CheckConfig

Implements ns3::QueueDisc.

Definition at line 503 of file codel-queue-disc.cc.

References NS_LOG_FUNCTION.

◆ NewtonStep()

uint16_t ns3::CoDelQueueDisc::NewtonStep	(	uint16_t	recInvSqrt,
		uint32_t	count
	)

staticprivate

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)

Parameters

recInvSqrt	reciprocal value of sqrt (count)
count	count value

Returns: The new recInvSqrt value

Definition at line 155 of file codel-queue-disc.cc.

References NS_LOG_FUNCTION_NOARGS, and REC_INV_SQRT_SHIFT.

Referenced by DoDequeue().

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◆ OkToDrop()

bool ns3::CoDelQueueDisc::OkToDrop	(	Ptr< QueueDiscItem >	item,
		uint32_t	now
	)

private

Determine whether a packet is OK to be dropped.

The packet may not be actually dropped (depending on the drop state)

Parameters

item	The packet that is considered
now	The current time represented as 32-bit unsigned integer (us)

Returns: True if it is OK to drop the packet (sojourn time above target for at least interval)

Definition at line 198 of file codel-queue-disc.cc.

References CoDelTimeAfter(), CoDelTimeBefore(), ns3::QueueDisc::GetInternalQueue(), ns3::QueueDisc::GetNBytes(), m_firstAboveTime, m_interval, m_minBytes, m_target, ns3::Time::MS, ns3::Simulator::Now(), NS_LOG_FUNCTION, NS_LOG_INFO, NS_LOG_LOGIC, and Time2CoDel().

Referenced by DoDequeue().

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◆ Time2CoDel()

uint32_t ns3::CoDelQueueDisc::Time2CoDel ( Time t )

private

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 464 of file codel-queue-disc.cc.

References ns3::CODEL_SHIFT, and ns3::Time::GetNanoSeconds().

Referenced by DoDequeue(), and OkToDrop().

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Friends And Related Function Documentation

◆ ::CoDelQueueDiscControlLawTest

friend class ::CoDelQueueDiscControlLawTest

friend

Definition at line 115 of file codel-queue-disc.h.

◆ ::CoDelQueueDiscNewtonStepTest

friend class ::CoDelQueueDiscNewtonStepTest

friend

Definition at line 114 of file codel-queue-disc.h.

Member Data Documentation

◆ CE_THRESHOLD_EXCEEDED_MARK

constexpr const char* ns3::CoDelQueueDisc::CE_THRESHOLD_EXCEEDED_MARK

staticconstexpr

Initial value:

=

"CE threshold exceeded mark"

Sojourn time above CE threshold.

Definition at line 110 of file codel-queue-disc.h.

Referenced by CoDelQueueDiscBasicMark::Dequeue(), DoDequeue(), FqCoDelQueueDiscECNMarking::DoRun(), and FqCoDelQueueDiscL4sMode::DoRun().

◆ m_ceThreshold

Time ns3::CoDelQueueDisc::m_ceThreshold

private

Threshold above which to CE mark.

Definition at line 215 of file codel-queue-disc.h.

Referenced by DoDequeue(), and GetTypeId().

◆ m_count

TracedValue<uint32_t> ns3::CoDelQueueDisc::m_count

private

Number of packets dropped since entering drop state.

Definition at line 216 of file codel-queue-disc.h.

Referenced by DoDequeue(), and GetTypeId().

◆ m_dropNext

TracedValue<uint32_t> ns3::CoDelQueueDisc::m_dropNext

private

Time to drop next packet.

Definition at line 221 of file codel-queue-disc.h.

Referenced by DoDequeue(), GetDropNext(), and GetTypeId().

◆ m_dropping

TracedValue<bool> ns3::CoDelQueueDisc::m_dropping

private

True if in dropping state.

Definition at line 218 of file codel-queue-disc.h.

Referenced by DoDequeue(), and GetTypeId().

◆ m_firstAboveTime

uint32_t ns3::CoDelQueueDisc::m_firstAboveTime

private

Time to declare sojourn time above target.

Definition at line 220 of file codel-queue-disc.h.

Referenced by OkToDrop().

◆ m_interval

Time ns3::CoDelQueueDisc::m_interval

private

100 ms sliding minimum time window width

Definition at line 213 of file codel-queue-disc.h.

Referenced by DoDequeue(), GetInterval(), GetTypeId(), and OkToDrop().

◆ m_lastCount

TracedValue<uint32_t> ns3::CoDelQueueDisc::m_lastCount

private

Last number of packets dropped since entering drop state.

Definition at line 217 of file codel-queue-disc.h.

Referenced by DoDequeue(), and GetTypeId().

◆ m_minBytes

uint32_t ns3::CoDelQueueDisc::m_minBytes

private

Minimum bytes in queue to allow a packet drop.

Definition at line 212 of file codel-queue-disc.h.

Referenced by GetTypeId(), and OkToDrop().

◆ m_recInvSqrt

uint16_t ns3::CoDelQueueDisc::m_recInvSqrt

private

Reciprocal inverse square root.

Definition at line 219 of file codel-queue-disc.h.

Referenced by DoDequeue().

◆ m_target

Time ns3::CoDelQueueDisc::m_target

private

5 ms target queue delay

Definition at line 214 of file codel-queue-disc.h.

Referenced by GetTarget(), GetTypeId(), and OkToDrop().

◆ m_useEcn

bool ns3::CoDelQueueDisc::m_useEcn

private

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

Definition at line 210 of file codel-queue-disc.h.

Referenced by DoDequeue(), and GetTypeId().

◆ m_useL4s

bool ns3::CoDelQueueDisc::m_useL4s

private

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

Definition at line 211 of file codel-queue-disc.h.

Referenced by DoDequeue(), and GetTypeId().

◆ OVERLIMIT_DROP

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

staticconstexpr

Overlimit dropped packet.

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

Referenced by DoEnqueue(), CoDelQueueDiscBasicEnqueueDequeue::DoRun(), and CoDelQueueDiscBasicOverflow::DoRun().

◆ TARGET_EXCEEDED_DROP

constexpr const char* ns3::CoDelQueueDisc::TARGET_EXCEEDED_DROP

staticconstexpr

Initial value:

=

"Target exceeded drop"

Sojourn time above target.

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

Referenced by CoDelQueueDiscBasicDrop::Dequeue(), CoDelQueueDiscBasicMark::Dequeue(), DoDequeue(), FqCoDelQueueDiscECNMarking::DoRun(), FqCoDelQueueDiscL4sMode::DoRun(), and CoDelQueueDiscBasicEnqueueDequeue::DoRun().

◆ TARGET_EXCEEDED_MARK

constexpr const char* ns3::CoDelQueueDisc::TARGET_EXCEEDED_MARK

staticconstexpr

Initial value:

=

"Target exceeded mark"

Sojourn time above target.

Definition at line 108 of file codel-queue-disc.h.

Referenced by CoDelQueueDiscBasicMark::Dequeue(), DoDequeue(), FqCoDelQueueDiscECNMarking::DoRun(), and FqCoDelQueueDiscL4sMode::DoRun().

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

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

Public Member Functions

Static Public Member Functions

Static Public Attributes

Private Member Functions

Static Private Member Functions

Private Attributes

Friends

Additional Inherited Members

Detailed Description

Attributes

Attributes defined in parent class ns3::QueueDisc

TraceSources

TraceSources defined in parent class ns3::QueueDisc

Constructor & Destructor Documentation

◆ CoDelQueueDisc()

◆ ~CoDelQueueDisc()

Member Function Documentation

◆ CheckConfig()

◆ CoDelTimeAfter()

◆ CoDelTimeAfterEq()

◆ CoDelTimeBefore()

◆ CoDelTimeBeforeEq()

◆ ControlLaw()

◆ DoDequeue()

◆ DoEnqueue()

◆ GetDropNext()

◆ GetInterval()

◆ GetTarget()

◆ GetTypeId()

◆ InitializeParams()

◆ NewtonStep()

◆ OkToDrop()

◆ Time2CoDel()

Friends And Related Function Documentation

◆ ::CoDelQueueDiscControlLawTest

◆ ::CoDelQueueDiscNewtonStepTest

Member Data Documentation

◆ CE_THRESHOLD_EXCEEDED_MARK

◆ m_ceThreshold

◆ m_count

◆ m_dropNext

◆ m_dropping

◆ m_firstAboveTime

◆ m_interval

◆ m_lastCount

◆ m_minBytes

◆ m_recInvSqrt

◆ m_target

◆ m_useEcn

◆ m_useL4s

◆ OVERLIMIT_DROP

◆ TARGET_EXCEEDED_DROP

◆ TARGET_EXCEEDED_MARK