A Discrete-Event Network Simulator
API
cobalt-queue-disc.h
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1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
2 /*
3  * Copyright (c) 2019 NITK Surathkal
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation;
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  *
18  * Cobalt, the CoDel - BLUE - Alternate Queueing discipline
19  * Based on linux code.
20  *
21  * Ported to ns-3 by: Vignesh Kannan <vignesh2496@gmail.com>
22  * Harsh Lara <harshapplefan@gmail.com>
23  * Jendaipou Palmei <jendaipoupalmei@gmail.com>
24  * Shefali Gupta <shefaligups11@gmail.com>
25  * Mohit P. Tahiliani <tahiliani@nitk.edu.in>
26  *
27  */
28 
29 #ifndef COBALT_H
30 #define COBALT_H
31 
32 #include "ns3/queue-disc.h"
33 #include "ns3/nstime.h"
34 #include "ns3/boolean.h"
35 #include "ns3/data-rate.h"
36 #include "ns3/simulator.h"
37 #include "ns3/string.h"
38 #include "ns3/traced-value.h"
39 #include "ns3/random-variable-stream.h"
40 #include "ns3/trace-source-accessor.h"
41 
42 namespace ns3 {
43 
44 #define REC_INV_SQRT_CACHE (16)
45 #define DEFAULT_COBALT_LIMIT 1000
46 
47 class TraceContainer;
48 
59 class CobaltQueueDisc : public QueueDisc
60 {
61 public:
66  static TypeId GetTypeId (void);
67 
73  CobaltQueueDisc ();
74 
80  virtual ~CobaltQueueDisc ();
81 
87  Time GetTarget (void);
88 
94  Time GetInterval (void);
95 
101  int64_t GetDropNext (void);
102 
103  static constexpr const char* TARGET_EXCEEDED_DROP = "Target exceeded drop";
104  static constexpr const char* OVERLIMIT_DROP = "Overlimit drop";
105  static constexpr const char* FORCED_MARK = "forcedMark";
106 
112  double GetPdrop ();
113 
122  int64_t AssignStreams (int64_t stream);
123 
130  int64_t Time2CoDel (Time t);
131 
132 protected:
136  virtual void DoDispose (void);
137 
138 private:
139  virtual bool DoEnqueue (Ptr<QueueDiscItem> item);
140  virtual Ptr<QueueDiscItem> DoDequeue (void);
141  virtual Ptr<const QueueDiscItem> DoPeek (void);
142  virtual bool CheckConfig (void);
143 
147  virtual void InitializeParams (void);
148 
154  void NewtonStep (void);
155 
165  int64_t ControlLaw (int64_t t);
166 
167  void InvSqrt (void);
168 
179  void CacheInit (void);
180 
188  bool CoDelTimeAfter (int64_t a, int64_t b);
189 
196  bool CoDelTimeAfterEq (int64_t a, int64_t b);
197 
201  void CobaltQueueFull (int64_t now);
202 
206  void CobaltQueueEmpty (int64_t now);
207 
212  bool CobaltShouldDrop (Ptr<QueueDiscItem> item, int64_t now);
213 
214  // Common to CoDel and Blue
215  // Maintained by Cobalt
216  Stats m_stats;
217 
218  // Codel parameters
219  // Maintained by Cobalt
223  uint32_t m_recInvSqrt;
225 
226  // Supplied by user
229  bool m_useEcn;
230 
231  // Blue parameters
232  // Maintained by Cobalt
235 
236  // Supplied by user
237  double m_increment;
238  double m_decrement;
239  double m_Pdrop;
240 
241 };
242 
243 } // namespace ns3
244 
245 #endif /* COBALT_H */
bool CoDelTimeAfter(int64_t a, int64_t b)
Check if CoDel time a is successive to b.
Simulation virtual time values and global simulation resolution.
Definition: nstime.h:103
double m_Pdrop
Drop Probability.
Smart pointer class similar to boost::intrusive_ptr.
Definition: ptr.h:73
CobaltQueueDisc()
CobaltQueueDisc Constructor.
virtual bool CheckConfig(void)
Check whether the current configuration is correct.
int64_t Time2CoDel(Time t)
Return the unsigned 32-bit integer representation of the input Time object.
int64_t AssignStreams(int64_t stream)
Assign a fixed random variable stream number to the random variables used by this model...
static TypeId GetTypeId(void)
Get the type ID.
bool CoDelTimeAfterEq(int64_t a, int64_t b)
Check if CoDel time a is successive or equal to b.
QueueDisc is an abstract base class providing the interface and implementing the operations common to...
Definition: queue-disc.h:181
void CobaltQueueFull(int64_t now)
Called when the queue becomes full to alter the drop probabilities of Blue.
Time GetInterval(void)
Get the interval.
TracedValue< int64_t > m_dropNext
Time to drop next packet.
static constexpr const char * OVERLIMIT_DROP
Overlimit dropped packet.
void NewtonStep(void)
Calculate the reciprocal square root of m_count by using Newton&#39;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)
int64_t GetDropNext(void)
Get the time for next packet drop while in the dropping state.
virtual ~CobaltQueueDisc()
Destructor.
int64_t ControlLaw(int64_t t)
Determine the time for next drop CoDel control law is t + m_interval/sqrt(m_count).
void CobaltQueueEmpty(int64_t now)
Called when the queue becomes empty to alter the drop probabilities of Blue.
static constexpr const char * FORCED_MARK
forced marks by Codel on ECN-enabled
double m_increment
increment value for marking probability
Cobalt packet queue disc.
Stats m_stats
Cobalt statistics.
TracedValue< uint32_t > m_count
Number of packets dropped since entering drop state.
static constexpr const char * TARGET_EXCEEDED_DROP
Sojourn time above target.
bool m_useEcn
True if ECN is used (packets are marked instead of being dropped)
Every class exported by the ns3 library is enclosed in the ns3 namespace.
Ptr< UniformRandomVariable > m_uv
Rng stream.
TracedValue< bool > m_dropping
True if in dropping state.
virtual void DoDispose(void)
Dispose of the object.
uint32_t m_recInvSqrtCache[REC_INV_SQRT_CACHE]
Cache to maintain some initial values of InvSqrt.
virtual Ptr< const QueueDiscItem > DoPeek(void)
Return a copy of the next packet the queue disc will extract.
virtual bool DoEnqueue(Ptr< QueueDiscItem > item)
This function actually enqueues a packet into the queue disc.
Time m_target
5 ms target queue delay
virtual void InitializeParams(void)
Initialize the queue parameters.
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 Co...
double m_decrement
decrement value for marking probability
double GetPdrop()
Get the drop probability of Blue.
uint32_t m_lastUpdateTimeBlue
Blue&#39;s last update time for drop probability.
virtual Ptr< QueueDiscItem > DoDequeue(void)
This function actually extracts a packet from the queue disc.
#define REC_INV_SQRT_CACHE
Time GetTarget(void)
Get the target queue delay.
uint32_t m_recInvSqrt
Reciprocal inverse square root.
a unique identifier for an interface.
Definition: type-id.h:58
void CacheInit(void)
There is a big difference in timing between the accurate values placed in the cache and the approxima...
Time m_interval
100 ms sliding minimum time window width