1 Queue Scheduling Analysis The Computer Communication Lab (236340) - Winter 2004 Tanya Berezner Ana...

1

Queue Scheduling Analysis

The Computer Communication Lab (236340) - Winter 2004

Tanya BereznerAna GluzbandGitit Amihud

2

Introduction General network node (gateway) receives packets.

The packets are queued according to their ToS. The order of the transmission is determined by the specified scheduling algorithm.

The project includes: Simulation of a gateway that receives IP packets that distributed

according to the user specifications. Implementation of the following queuing scheduling algorithms:

WFQ ,DRR, and ODRR. Analysis of the algorithm’s performance.

3

The algorithms:

DRR – Deficit Round RobinIn this algorithm there is round robin between the non-empty queues. Each queue gets a quantum (according to it’s Tos) to transmit it’s packets. If the queue didn’t use all it’s quantum, the deficit quantum is saved for the next iterations.

WFQ – Weighted Fair Queuing In this algorithm each queue gets a part of the bandwidth, according to his Tos.We calculate the virtual finish time for transmission for each packet according to it’s ToS bandwidth, the number of active queues and the packet length. The next packet to dequeue will be the one with the smallest virtual finish time.

4

ODRR – Ordered Deficit Round RobinEach queue gets a number of units. The allocated units quantity is in accordance to the priority of the queue (high priority – more units – more bandwidth). The user sets an order between the queues (qOrderList). The qOrderList composed of the queues' number and their units quantum. the packets are drawn from the queues according to the qOrderList.

The deficit quantum is accomulated for each queue as in DRR. If the next packet chosen for transmission according to the

qOrderList doesn’t fit in the slot, the algorithm tries to find another packet in another queue head that fits the slot, and accomulated quantum for all skipped queues.

There is a "saving" mechanism that puts a queue that has accumulated too much quantum in the PassLimitList. In the beginning of each slot, the queues in PassLimitList will transmit first.

The algorithms: cont.

6

Partial Class diagram

Generator

int Len[NUM_OF_LEN];double LenPercent[NUM_OF_LEN];int TosNumdouble TosPercent[MAX_NUM_OF_TOS];CString fileName

Generate()CreateIpFile()

7

DRRGateway

double DeficitCounter[MAX_NUM_OF_TOS];int currentQueue

enqueue()dequeue()long nextPacketLen()DRRgateway()

WFQGateway

int PercentWeights[MAX_NUM_OF_TOS];bool activeQueues[MAX_NUM_OF_TOS];double queueFinishTime[MAX_NUM_OF_TOS];int bandwidthOfActivedouble systemTime

enqueue()dequeue()long nextPacketLen()WFQgateway()

ODRRGateway

int units[MAX_NUM_OF_TOS];int DeficitCounter[MAX_NUM_OF_TOS]int currentQueueint deficitLimitlist<Pair> OrderList

enqueue()dequeue()long nextPacketLen()ODRRgateway()

Stat

ofstream dFileofstream tFileofstream lFile

Stat()void update()void printStat()

gateway<class T>

queue<T>* queuesint slotSize;double totalBandwidthdouble slotTimedouble time

gateway()run()bool getNextIpPacket()virtual enqueue()virtual dequeue()virtual long nextPacketLen()

Partial Class diagram – cont.

8

Partial Class diagram – cont.IPpack

int toslong lenlong timelong num

IPpack()

DRRIpPack

DRRIpPack()WFQIpPack

double finishTime

WFQIpPack()

ODRRIpPack

ODRRIpPack()

9

ClassesClass Generate:

This class receives from the user the following parameter: Lamda – the mean value of the exponential distribution of arriving

packets. Lengths of packets. Lengths distribution. ToS distribution. Input file name of the generated file.

The class generates a file containing IP packets in the following format:

Lamda Number of different ToSes

Serial number length ToS Arrival timeSerial number length ToS Arrival time…

We also allow the user to supply an existing file of IP packets. The IP packets in this file should be in the above format.

10

template<class T> gateway An abstract template class that represent the gateway.

This class holds our “database”: a template array of queues. Each ToS has it’s own queue.

This class implements the run() method. This method manages the time and the slots. It synchronizes the enqueue() and dequeue() methods.

This class declares 3 pure virtual functions that derived classes should implement according to the algorithm:

virtual enqueue() = 0; virtual dequeue() = 0; virtual long nextPacketLen() = 0;

Classes – cont.

11

class IPpack This class represents a basic IP packet and contains the

following fields: ToS Length Arrival time Serial number in the file.

The following 3 classes inherit from this class : Class DRRIpPack Class WFQIpPack Class ODRRIpPack

The derived classes add member data according to the specific algorithm: for example class WFQIpPack adds data member finishTime that represent the virtual finish time.

Classes – cont.

12

Class DRRgateway This class inherits public from class: gateway<DRRIpPack>

Class WFQgateway This class inherits public from class: gateway<WFQIpPack>

Class ODRRgateway This class inherits public from class: gateway<ODRRIpPack>

All the three classes implement the 3 virtual methods (enqueue(), dequeue(), nextPacketLen()) that were declared in their base class according to their algorithms.

Classes – cont.

14

GUI

15

GUI - cont

16

GUI - cont

17

GUI - cont

18

GUI - cont

20

The constant parameters:

Length sizes = 5,10,15,20,25 Queue limit = 1000 bits ToS weights in percents = 50,30,20 Total bandwidth = 100 Slot size = 100 Proportion for DRR = 1 Deficit limit = 30 Unit =5 bits Number of generated packets = 10,000

21

We analyzed the following packets distributions:

Packets length 5 10 15 20 25

Length distribution

50 30 10 7 3


Length distribution

3 7 10 30 50


Length distribution

20 20 20 20 20


Length distribution

20 20 20 20 20


Length distribution

20 20 20 20 201.

2.

3.

4.

5.

ToS 1 2 3

distribution 34 33 33

ToS 1 2 3


ToS 1 2 3


ToS 1 2 3


ToS 1 2 3


22


Length distribution

20 20 20 20 201.

ToS 1 2 3


DRR - delay

0

10

20

30

40

50

60

Load

Del

ay (s

ec)

ToS1

ToS2

ToS3

23


Length distribution

20 20 20 20 201.

ToS 1 2 3


WFQ - delay

0

50

100

150

200

Load

Del

ay (s

ec) ToS1

ToS2

ToS3

24


Length distribution

20 20 20 20 201.

ToS 1 2 3


ODRR default order - delay

0

10

20

30

40

50

60

0.07

50.

225

0.37

50.

525

0.67

50.

825

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

25


Length distribution

20 20 20 20 201.

ToS 1 2 3


ODRR interleaved - delay

0

10

20

30

40

50

60

0.07

50.

225

0.37

50.

525

0.67

50.

825

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

26


Length distribution

20 20 20 20 201.

ToS 1 2 3


THROUGHPUT

0

0.2

0.4

0.6

0.8

1

0.08

0.23

0.38

0.53

0.68

0.83

0.98

1.13

1.28

1.43

1.58

1.73

Load

Thro

ughp

ut

DRR

WFQ

ODRR

ODRR default

27


Length distribution

20 20 20 20 201.

ToS 1 2 3


THROUGHPUT ZOOM

0.89

0.9

0.91

0.92

0.93

0.94

0.95

0.96

0.98

1.05

1.13 1.2

1.28

1.35

1.43 1.5

1.58

1.65

1.73 1.8

Load

Th

rou

gh

pu

t DRR

WFQ

ODRR

ODRR default

28


Length distribution

20 20 20 20 201.

ToS 1 2 3


Lost packets for ToS1

0100200300400500600700

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

lost

pac

kets DRR

WFQ

ODRR

ODRR default


0

500

1000

1500

2000

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

lost

pac

kets DRR

WFQ

ODRR

ODRR default


0

500

1000

1500

2000

2500

3000

Load

lost

packets DRR

WFQ

ODRR

ODRR default

29


Length distribution

50 30 10 7 32.

ToS 1 2 3


DRR - delay

0

10

20

30

40

50

0.05

0.14

0.23

0.32

0.41 0.5

0.59

0.69

0.78

0.87

0.96

1.05

1.14

1.24

1.33

Load

del

ay (

sec) ToS1

ToS2

ToS3

30


Length distribution

50 30 10 7 32.

ToS 1 2 3


WFQ - delay

0

20

40

60

80

100

0.04

575

0.18

3

0.32

025

0.45

75

0.59

475

0.73

2

0.86

925

1.00

65

1.14

375

1.28

1

Load

del

ay (

sec) ToS1

ToS2

ToS3

31


Length distribution

50 30 10 7 32.

ToS 1 2 3



0

10

20

30

40

50

0.05

0.14

0.23

0.32

0.41 0.5

0.59

0.69

0.78

0.87

0.96

1.05

1.14

1.24

1.33

Load

del

ay (

sec) ToS1

ToS2

ToS3

32


Length distribution

50 30 10 7 32.

ToS 1 2 3



0

10

20

30

40

50

0.05

0.14

0.23

0.32

0.41 0.5

0.59

0.69

0.78

0.87

0.96

1.05

1.14

1.24

1.33

Load

del

ay (

sec) ToS1

ToS2

ToS3

33


Length distribution

50 30 10 7 32.

ToS 1 2 3


Througput

0

0.2

0.4

0.6

0.8

1

1.2

0.04

575

0.18

3

0.32

025

0.45

75

0.59

475

0.73

2

0.86

925

1.00

65

1.14

375

1.28

1

Load

Th

rou

gp

ut DRR

WFQ

ODRR default

ODRR interleaved

34


Length distribution

50 30 10 7 32.

ToS 1 2 3


Throughput - zoom

0.9

0.91

0.92

0.93

0.94

0.95

0.96

0.97

0.92

0.96

1.01

1.05 1.1

1.14

1.19

1.24

1.28

1.33

Load

Th

rou

gh

pu

t DRR

WFQ

ODRR default

ODRR interleaved

35


Length distribution

50 30 10 7 32.

ToS 1 2 3



0100200300400500600700800

Load

lost

pac

kets DRR

WFQ

ODRR

ODRR default


0

500

1000

1500

2000

2500

Loadlo

st p

acke

ts DRR

WFQ

ODRR

ODRR default

36


Length distribution

3 7 10 30 503.

ToS 1 2 3


DRR - delay

010

203040

5060

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

37


Length distribution

3 7 10 30 503.

ToS 1 2 3


WFQ - delay

0

50

100

150

200

250

0.10

43

0.31

28

0.52

13

0.72

98

0.93

83

1.14

68

1.35

53

1.56

38

1.77

23

1.98

08

2.18

93

2.39

78

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

38


Length distribution

3 7 10 30 503.

ToS 1 2 3



010

203040

5060

0.10

43

0.31

28

0.52

13

0.72

98

0.93

83

1.14

68

1.35

53

1.56

38

1.77

23

1.98

08

2.18

93

2.39

78

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

39


Length distribution

3 7 10 30 503.

ToS 1 2 3



010

203040

5060

0.10

43

0.31

28

0.52

13

0.72

98

0.93

83

1.14

68

1.35

53

1.56

38

1.77

23

1.98

08

2.18

93

2.39

78

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

40


Length distribution

3 7 10 30 503.

ToS 1 2 3


THROUGHPUT

0

0.2

0.4

0.6

0.8

1

0.1

0.3

1

0.5

2

0.7

3

0.9

4

1.1

5

1.3

6

1.5

6

1.7

7

1.9

8

2.1

9

2.4

Load

Th

rou

gh

pu

t DRR

WFQ

ODRR

ODRR default

41


Length distribution

3 7 10 30 503.

ToS 1 2 3


THROUGHPUT ZOOM

0.8850.89

0.8950.9

0.9050.91

0.9150.92

0.925

1.35

525

1.56

375

1.77

225

1.98

075

2.18

925

2.39

775

Load

Th

rou

gh

pu

t DRR

WFQ

ODRR

ODRR default

42


Length distribution

3 7 10 30 503.

ToS 1 2 3



0200400600800

1000120014001600

Load

lost

packets DRR

WFQ

ODRR

ODRR default


0

500

1000

1500

2000

2500

3000

3500

1.0

4

1.2

5

1.4

6

1.6

7

1.8

8

2.0

9

2.2

9

2.5

Load

lost

packets DRR

WFQ

ODRR

ODRR default


0500

100015002000250030003500

0.93

83

1.14

68

1.35

53

1.56

38

1.77

23

1.98

08

2.18

93

2.39

78

Load

lost

pa

cke

ts DRR

WFQ

ODRR

ODRR default

43


Length distribution

20 20 20 20 204.

ToS 1 2 3


DRR - delay

0

10

20

30

40

50

60

0.07

50.

225

0.37

50.

525

0.67

50.

825

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

44


Length distribution

20 20 20 20 204.

ToS 1 2 3


WFQ - delay

0

10

20

30

40

50

0.07

50.

225

0.37

50.

525

0.67

50.

825

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

45


Length distribution

20 20 20 20 204.

ToS 1 2 3



0

10

20

30

40

50

60

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

46


Length distribution

20 20 20 20 204.

ToS 1 2 3



0

10

20

30

40

50

60

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

47


Length distribution

20 20 20 20 204.

ToS 1 2 3


THROUGHPUT

0

0.2

0.4

0.6

0.8

1

0.0

8

0.2

3

0.3

8

0.5

3

0.6

8

0.8

3

0.9

8

1.1

3

1.2

8

1.4

3

1.5

8

1.7

3Load

Th

rou

gh

pu

t DRR

WFQ

ODRR

ODRR default

48


Length distribution

20 20 20 20 204.

ToS 1 2 3


THROUGHPUT ZOOM

0.89

0.9

0.91

0.92

0.93

0.94

0.95

0.96

0.98

1.05

1.13 1.2

1.28

1.35

1.43 1.5

1.58

1.65

1.73 1.8

Load

Th

rou

gh

pu

t DRR

WFQ

ODRR

ODRR default

49


Length distribution

20 20 20 20 204.

ToS 1 2 3



0

500

1000

1500

2000

2500

3000

Load

lost

packets DRR

WFQ

ODRR

ODRR default


0

500

1000

1500

2000

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

lost

pac

kets DRR

WFQ

ODRR

ODRR default


0

200

400

600

800

1000

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

lost

pac

kets DRR

WFQ

ODRR

ODRR default

50


Length distribution

20 20 20 20 205.

ToS 1 2 3


DRR - delay

0

10

20

30

40

50

0.07

50.

225

0.37

50.

525

0.67

50.

825

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

51


Length distribution

20 20 20 20 205.

ToS 1 2 3


WFQ - delay

0

50

100

150

200

250

0.07

50.

225

0.37

50.

525

0.67

50.

825

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

52


Length distribution

20 20 20 20 205.

ToS 1 2 3



0

10

20

30

40

50

0.07

50.

225

0.37

50.

525

0.67

50.

825

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

53


Length distribution

20 20 20 20 205.

ToS 1 2 3



0

10

20

30

40

50

0.07

50.

225

0.37

50.

525

0.67

50.

825

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

De

lay

(s

ec

)

ToS1

ToS2

ToS3

54


Length distribution

20 20 20 20 205.

ToS 1 2 3


THROUGHPUT

0

0.2

0.4

0.6

0.8

1

0.0

8

0.2

3

0.3

8

0.5

3

0.6

8

0.8

3

0.9

8

1.1

3

1.2

8

1.4

3

1.5

8

1.7

3Load

Th

rou

gh

pu

t DRR

WFQ

ODRR

ODRR default

55


Length distribution

20 20 20 20 205.

ToS 1 2 3


THROUGHPUT ZOOM

0.89

0.9

0.91

0.92

0.93

0.94

0.95

0.98

1.05

1.13 1.2

1.28

1.35

1.43 1.5

1.58

1.65

1.73 1.8

Load

Th

rou

gh

pu

t DRR

WFQ

ODRR

ODRR default

56


Length distribution

20 20 20 20 205.

ToS 1 2 3



0

200

400

600

800

1000

0.97

51.

125

1.27

51.

425

1.57

51.

725

Load

lost

pac

kets DRR

WFQ

ODRR

ODRR default


0

1000

2000

3000

4000

5000

Load lo

st p

acke

ts DRR

WFQ

ODRR

ODRR default

58

When there are more small packets:Delay is smaller in all algorithms.The throughput reaches it’s maximal values in higher load.There is less lost packets for all algorithms.

When there are more large packets, we observe the opposite tendencies.

The throughput of ODRR is better than the throughput of WFQ and DRR.Possible reason: slot filling mechanism.

WFQ is more sensitive to changes in ToS distribution. A small change in ToS distribution leads to a bigger change in delay and number of lost packets in comparison with the other algorithms.Possible reason: The depart time of the packet in WFQ depends on the queue state on it’s arrival.

For ODRR, the default order is better than interleavingfor distribution with more big packets.

1 Queue Scheduling Analysis The Computer Communication Lab (236340) - Winter 2004 Tanya Berezner Ana...

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