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ns3::CobaltQueueDisc Class Reference

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.
 
 ~CobaltQueueDisc () override
 Destructor.
 
int64_t AssignStreams (int64_t stream)
 Assign a fixed random variable stream number to the random variables used by this model.
 
int64_t GetDropNext () const
 Get the time for next packet drop while in the dropping state.
 
Time GetInterval () const
 Get the interval.
 
double GetPdrop () const
 Get the drop probability of Blue.
 
Time GetTarget () const
 Get the target queue delay.
 
int64_t Time2CoDel (Time t) const
 Return the unsigned 32-bit integer representation of the input Time object.
 
- 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< QueueDiscItemDequeue ()
 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< InternalQueueGetInternalQueue (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< NetDeviceQueueInterfaceGetNetDeviceQueueInterface () 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< PacketFilterGetPacketFilter (std::size_t i) const
 Get the i-th packet filter.
 
Ptr< QueueDiscClassGetQueueDiscClass (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 StatsGetStats ()
 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.
 
QueueDiscoperator= (const QueueDisc &)=delete
 
Ptr< const QueueDiscItemPeek ()
 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< ObjectGetObject () 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< ObjectGetObject (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.
 
SimpleRefCountoperator= (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 * FORCED_MARK
 forced marks by Codel on ECN-enabled
 
static constexpr const char * OVERLIMIT_DROP = "Overlimit drop"
 Overlimit dropped packet.
 
static constexpr const char * TARGET_EXCEEDED_DROP
 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.
 

Protected Member Functions

void DoDispose () override
 Dispose of the object.
 
- 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.
 

Private Member Functions

void CacheInit ()
 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.
 
bool CheckConfig () override
 Check whether the current configuration is correct.
 
void CobaltQueueEmpty (int64_t now)
 Called when the queue becomes empty to alter the drop probabilities of Blue.
 
void CobaltQueueFull (int64_t now)
 Called when the queue becomes full to alter the drop probabilities of Blue.
 
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 parallelly.
 
bool CoDelTimeAfter (int64_t a, int64_t b)
 Check if CoDel time a is successive to b.
 
bool CoDelTimeAfterEq (int64_t a, int64_t b)
 Check if CoDel time a is successive or equal to b.
 
int64_t ControlLaw (int64_t t)
 Determine the time for next drop CoDel control law is t + m_interval/sqrt(m_count).
 
Ptr< QueueDiscItemDoDequeue () override
 This function actually extracts a packet from the queue disc.
 
bool DoEnqueue (Ptr< QueueDiscItem > item) override
 This function actually enqueues a packet into the queue disc.
 
Ptr< const QueueDiscItemDoPeek () override
 Return a copy of the next packet the queue disc will extract.
 
void InitializeParams () override
 Initialize the queue parameters.
 
void InvSqrt ()
 Updates the inverse square root.
 
void NewtonStep ()
 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_blueThreshold
 Threshold to enable blue enhancement.
 
Time m_ceThreshold
 Threshold above which to CE mark.
 
TracedValue< uint32_tm_count
 Number of packets dropped since entering drop state.
 
double m_decrement
 decrement value for marking probability
 
TracedValue< int64_t > m_dropNext
 Time to drop next packet.
 
TracedValue< bool > m_dropping
 True if in dropping state.
 
double m_increment
 increment value for marking probability
 
Time m_interval
 sliding minimum time window width
 
uint32_t m_lastUpdateTimeBlue
 Blue's last update time for drop probability.
 
double m_pDrop
 Drop Probability.
 
uint32_t m_recInvSqrt
 Reciprocal inverse square root.
 
uint32_t m_recInvSqrtCache [REC_INV_SQRT_CACHE]
 Cache to maintain some initial values of InvSqrt.
 
Stats m_stats
 Cobalt statistics.
 
Time m_target
 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)
 
Ptr< UniformRandomVariablem_uv
 Rng stream.
 

Additional Inherited Members

- Public Types inherited from ns3::QueueDisc
typedef Queue< QueueDiscItemInternalQueue
 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...
 

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

  • 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: constructwriteread
  • 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
  • Decrement: Pdrop decrement Value
    • Set with class: ns3::DoubleValue
    • Underlying type: double -1.79769e+308:1.79769e+308
    • Initial value: 0.000244141
    • Flags: constructwriteread
  • Increment: Pdrop increment value
    • Set with class: ns3::DoubleValue
    • Underlying type: double -1.79769e+308:1.79769e+308
    • Initial value: 0.00390625
    • Flags: constructwriteread
  • Interval: The Cobalt 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.
  • Pdrop: Marking Probability
    • Set with class: ns3::DoubleValue
    • Underlying type: double -1.79769e+308:1.79769e+308
    • Initial value: 0
    • Flags: constructwriteread
  • 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: 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

TraceSources

TraceSources defined in parent class ns3::QueueDisc

Size of this type is 1648 bytes (on a 64-bit architecture).

Definition at line 60 of file cobalt-queue-disc.h.

Constructor & Destructor Documentation

◆ CobaltQueueDisc()

ns3::CobaltQueueDisc::CobaltQueueDisc ( )

CobaltQueueDisc Constructor.

Create a Cobalt queue disc

Definition at line 148 of file cobalt-queue-disc.cc.

References InitializeParams(), m_uv, and NS_LOG_FUNCTION.

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◆ ~CobaltQueueDisc()

ns3::CobaltQueueDisc::~CobaltQueueDisc ( )
override

Destructor.

Destructor

Definition at line 162 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
streamfirst stream index to use
Returns
the number of stream indices assigned by this model

Definition at line 168 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 ( )
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 239 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 ( )
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 301 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
nowtime in CoDel time units (microseconds)

Definition at line 419 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, 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
nowtime in CoDel time units (microseconds)

Definition at line 399 of file cobalt-queue-disc.cc.

References CoDelTimeAfter(), m_count, m_dropNext, m_dropping, m_increment, m_lastUpdateTimeBlue, m_pDrop, m_target, 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 parallelly.

Returns
true if the packet should be dropped, false otherwise
Parameters
itemcurrent packet
nowtime in CoDel time units (microseconds)

Definition at line 439 of file cobalt-queue-disc.cc.

References 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(), 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
aleft operand
bright operand
Returns
true if a is greater than b

Definition at line 190 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
aleft operand
bright operand
Returns
true if a is greater than or equal to b

Definition at line 196 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
tCurrent next drop time
Returns
The new next drop time:

Definition at line 268 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 ( )
overrideprivatevirtual

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 358 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 ( )
overrideprotectedvirtual

Dispose of the object.

Reimplemented from ns3::Object.

Definition at line 275 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)
overrideprivatevirtual

This function actually enqueues a packet into the queue disc.

Parameters
itemitem to enqueue
Returns
True if the operation was successful; false otherwise

Implements ns3::QueueDisc.

Definition at line 332 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 ( )
overrideprivatevirtual

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 283 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 ( ) 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 220 of file cobalt-queue-disc.cc.

References m_dropNext.

◆ GetInterval()

Time ns3::CobaltQueueDisc::GetInterval ( ) const

Get the interval.

Returns
The interval

Definition at line 214 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 157 of file cobalt-queue-disc.cc.

References m_pDrop.

◆ GetTarget()

Time ns3::CobaltQueueDisc::GetTarget ( ) const

Get the target queue delay.

Returns
The target queue delay

Definition at line 208 of file cobalt-queue-disc.cc.

References m_target.

◆ GetTypeId()

◆ InitializeParams()

void ns3::CobaltQueueDisc::InitializeParams ( )
overrideprivatevirtual

Initialize the queue parameters.

Implements ns3::QueueDisc.

Definition at line 176 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 ( )
private

Updates the inverse square root.

Definition at line 255 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 ( )
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 226 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
tthe input Time Object
Returns
the unsigned 32-bit integer representation

Definition at line 202 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
staticconstexpr
Initial value:
=
"CE threshold exceeded mark"

Sojourn time above CE threshold.

Definition at line 109 of file cobalt-queue-disc.h.

Referenced by CobaltShouldDrop(), CobaltQueueDiscCeThresholdTest::Dequeue(), FqCobaltQueueDiscEcnMarking::DoRun(), and FqCobaltQueueDiscL4sMode::DoRun().

◆ FORCED_MARK

constexpr const char* ns3::CobaltQueueDisc::FORCED_MARK
staticconstexpr
Initial value:
=
"forcedMark"

forced marks by Codel on ECN-enabled

Definition at line 107 of file cobalt-queue-disc.h.

Referenced by CobaltShouldDrop(), CobaltQueueDiscMarkTest::Dequeue(), FqCobaltQueueDiscEcnMarking::DoRun(), and FqCobaltQueueDiscL4sMode::DoRun().

◆ m_blueThreshold

Time ns3::CobaltQueueDisc::m_blueThreshold
private

Threshold to enable blue enhancement.

Definition at line 247 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 245 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 234 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 256 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 235 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 236 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 255 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 242 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 252 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 257 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 237 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]
private
Initial value:
= {
0}

Cache to maintain some initial values of InvSqrt.

Definition at line 238 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 230 of file cobalt-queue-disc.h.

◆ m_target

Time ns3::CobaltQueueDisc::m_target
private

target queue delay

Definition at line 243 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 244 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 246 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 251 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 106 of file cobalt-queue-disc.h.

Referenced by DoEnqueue(), CobaltQueueDiscBasicEnqueueDequeue::DoRun(), and CobaltQueueDiscDropTest::RunDropTest().

◆ TARGET_EXCEEDED_DROP

constexpr const char* ns3::CobaltQueueDisc::TARGET_EXCEEDED_DROP
staticconstexpr

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