performance evaluation of ip telephony over university network a project funded by university fast...

Performance Evaluation of IP Performance Evaluation of IP Telephony Telephony

over University Networkover University Network

A project funded by University Fast Track

ByM. Kousa, M Sait, A. Shafi, A. Khan

King Fahd Univ. of Petroleum & Minerals (KFUPM)

Dhahran, Saudi Arabia.

EE Seminar, March 2009EE Seminar, March 2009 Evaluation of VoIP over University NetworksEvaluation of VoIP over University Networks 22

Presentation OutlinesPresentation Outlines

Definition of VoIP. Performance and Quality Indicators. University Networks Assessment Designs. LAN Assessment Results Wi-FI Assessment Results. ADSL Assessment Results Conclusions.


What is IPTWhat is IPT

Special telephone sets connected directly to a network port (RJ45)

Carrying voice traffic over the data network.

Circuit-Switched versus Packet-switched

Enabler: VoIP protocols.


Performance and Quality IndicatorsPerformance and Quality Indicators Delay (or Latency): Time takes a packet to

make its way through a network end-to-end. Packet Loss: Due to errors in Header of

Buffer overflow. Jitter: The measure of the variation of

packet arrival time. Mean Opinion Square (MOS): The most

well-known measure of voice quality. MOS (Lower Limit) User Satisfaction

4.34 Very satisfied 4.03 Satisfied 3.60 Some users dissatisfied 3.10 Many users dissatisfied 2.58 Nearly all users dissatisfied


Coding and Compression AlgorithmsCoding and Compression Algorithms

Co

de

c

De

fau

lt D

ata

Ra

te

(kb

ps

)

Pa

ck

eti

zati

on

D

ela

y

Th

eo

reti

ca

l M

ax

imu

m M

OS

G.711u; G.711a 64 1.0 ms 4.40

G.723.1 ACELP 5.3 67.5 ms 3.69

The process of converting Analog voice signals to digital data signals is done with a coder-decoder (CODEC).

codec selection depends on bandwidth and quality.


University NetworksUniversity Networks

Bldg . 3 Bldg . 4 Bldg . 5 Bldg . 6 Bldg . 24Bldg . 23Bldg . 22Bldg . 21Bldg . 20Bldg . 19Bldg . 17Bldg . 16Bldg . 15Bldg . 11Bldg . 10Bldg . 9Bldg . 8Bldg . 7

Bldg . 14

ITC

Bldg. 29 Bldg

. 45

Bld

g.

36

Bldg . 14

ITC

North Gate

Main Gate

Bldg 40

Press

Clinic

Tel . Exch

ELC

Bldg . 28

Schools

Tel . Exch

Bldg 53

Bldg 54

Bldg 34

ERL

Faculty Housing

DCC Internet(Awalnet)

ATM

Currently 4 Mbps

Voice over IP (VoIP) assessment is performed for all four kinds of university networks.


University Academic Buildings considered for LAN University Academic Buildings considered for LAN Assessment Test DesignAssessment Test Design

List of University Academic Buildings, considered for VoIP Test

S. No.

Building Number

Reason Approx. No. of Telephone

Users 1 14 Core data network 250

2 34 Core voice network 35 3 21 Largest office building have the

highest number of telephone users and highest expected number of incoming and outgoing calls

700

4 5 Tallest academic building and situated on the edge of wireless connection to DCC.

100

5 55 Building with highest number of intermediate routers and home to telephone operators

65

6 59 Largest academic building 300


University LAN Assessment Test DesignUniversity LAN Assessment Test Design

LAN Assessment Physical Connectivity Diagram

B-34

B-55Tel . Exch

B-21

B-59BackboneNetwork

B-5

B-141000-Base LX

Uplink

Distribution LayerUTIL

STAT

DUPLX

SPEED

SYSTEM

RPSMODE

CATALYST 3550

1 2 3 4 5 6 7 8 9 10

11

12

UTILSTAT

DUPLEXSPEED

SYSTEMRPS

CATALYST 35503

4

5

6

7

8

9

10

11

12

1

2

15

16

17

18

19

20

21

22

23

24

13

14

1 2

Layer-3 Switch

Layer-2 Switch

1000

-Bas

e T

U

plin

k

1000-Base LX Uplink

Computer

Laptop

Access Layer

100-Base T

Inside a Building



LAN Assessment Logical Connectivity Diagram

B-5

B-55B-59

B-14

B-34B-21



Worst-case scenario: half of the telephone users are busy on calls.

Calls originating from any building are distributed to all other buildings according to their user intensity.

Figure shows concurrent number of calls between any two buildings.

All calls are assumed to last for 3 minutes, while the inter-call delay for the calls on the same link was set to 5 minutes.

B-14B-5

B-21

B-59 B-55

B-34

3

11

22

91

4

2

9

26

3

1

16

3Calls=7

Calls=37Calls=18

Calls=13

Calls=66

Calls=43


LAN Assessment ResultsLAN Assessment Results

Call Quality Summary- G723

Acceptable100%

Good0%

Poor< 1%Unavailable

< 1%

Good

Acceptable

Poor

Unavailable

Call Quality Summary- G711

Good100%

Acceptable0%

Poor< 1%

Unavailable< 1%

Good

Acceptable

Poor

Unavailable

Number of VoIP Probes 6

Number of links 15

Total number of concurrent calls emulated in the test

92

Schedule Duration of Test 5 days

Total number of calls emulated in the test 93748


LAN Assessment ResultsLAN Assessment ResultsMOS ResultsMOS Results

Call Quality Summary by Call Codec

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

MO

S

MOS 4.38 3.65

G.711u (64 kbps) G.723.1-ACELP (5.3 kbps)


University LAN UtilizationUniversity LAN Utilization

Building 21 LAN Utilization for a Year 2007-08

Building 14 LAN Utilization for a Year 2007-08


University Wireless LAN (WiFi)University Wireless LAN (WiFi)

•IEEE 802.11g standard which supports up to 54 Mbps.• The wireless access points are back connected to the layer-2 switches• Layer-2 switches are connected to the building layer-3 switch.• Layer-3 switch forwards the data over the fiber-optic link to the university core network.

Distribution Layer

Layer-3 Switch

Layer-2 PoE Switch

Access Layer

UTIL

STAT

DUPLX

SPEED

SYSTEM

RPS

MODE

CATALYST 3550

1 2 3 4 5 6 7 8 9 10

11

12

SYST RPS

STRT DUPLXSPEEDUTIL

MODE

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Catalyst 2950SERIES10Base-T/100Base-TX

LaptopLaptop

Access Point

CISCO AIRONET 1100 SERIES

WIRELESS ACCESS POINT

LaptopLaptop

Access Point



Distribution Layer

Layer-3 Switch

Layer-2 PoE Switch

Access Layer

UTIL

STAT

DUPLX

SPEED

SYSTEM

RPS

MODE

CATALYST 3550

1 2 3 4 5 6 7 8 9 10

11

12

SYST RPS

STRT DUPLXSPEEDUTIL

MODE

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24


LaptopLaptop

Access Point



BackboneNetwork


WiFi Assessment Tests Design, WiFi Assessment Tests Design, Physical Connectivity (Bldg 59)Physical Connectivity (Bldg 59)

Room 0032 (very good signal)Room 0072 – PC1 (good signal)Room 0072 – PC2 (good signal, Linked with same AP as of PC1)Room 0081 (far from AP, poor signal)Room 1079 (far from AP, poor signal)Room 2078 (Excellent signal)

Distribution LayerLayer-3 Switch

Layer-2 PoE Switch

Access Layer

UTIL

STAT

DUPLX

SPEED

SYSTEM

RPS

MODE

CATALYST 3550

1 2 3 4 5 6 7 8 9 10

11

12

AP1

SYST RPS

STRT DUPLXSPEEDUTIL

MODE

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24


R-0032



R-2078



R-0071-PC2

R-1079



R-0071-PC1



R-0081



AP2

AP3

AP4

AP5


WiFi Assessment Tests Design, WiFi Assessment Tests Design, Logical ConnectivityLogical Connectivity

Three levels of traffic intensity

Low: one call is initiated between any pair Medium: 2 simultaneous calls are initiated between any pair High: 4 simultaneous calls are initiated between any pair.

R-2078

R-0071-PC1

R-0081

R-0071-PC2

R-0032

R-1079


WiFi Assessment Results WiFi Assessment Results G711 – 1 CallG711 – 1 Call

The performance seems to be pretty good for more than 99% of the calls. The average delay was always below 45 ms, which is quite acceptable. The lost data was negligible (less than 0.03%).

Number of Node 6

Number of Links 15

Number of concurrent calls between any two nodes 1

Number of concurrent calls per node 5 x 1 = 5

Total number of concurrent calls emulated in the test 15 x 1 = 15

Schedule Duration of Test 1 day



WiFi Assessment Results WiFi Assessment Results G711 – 2 Calls: Call Quality (MOS)G711 – 2 Calls: Call Quality (MOS)

Number of VoIP Probes 6

Number of Links 15

Number of concurrent calls between any two VoIP probes 2

Number of concurrent calls per VoIP probe 5 x 2 = 10




Call Quality Summary

Good67%

Poor33%

Acceptable< 1%

Unavailable< 1%

Good

Acceptable

Poor

Unavailable


WiFi Assessment Results WiFi Assessment Results G711 – 2 Calls: Factors Affecting MOSG711 – 2 Calls: Factors Affecting MOS

The percentage effect of each of the other three factors; delay, jitter, lost data, is shown in figure. The source of poor quality is mainly due to delay (51%) and lost data (41%). The effect of jitter is much smaller (8%). Factors Affecting Call Quality

Delay51%

Jitter8%

Lost Data41%

Delay

Jitter

Lost Data

Codec


WiFi: G711 – 2 Calls: Call Quality by Call GroupWiFi: G711 – 2 Calls: Call Quality by Call Group

Call Quality Summary by Call Group - Bottom 5

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

MO

S

MOS 1.30 1.31 1.32 1.32 1.35

59-0032-59-0081 : G.711u (64 kbps)

59-1079-59-0081 : G.711u (64 kbps)

59-0081-59-0071-P C1 : G.711u (64

kbps)

59-0071-P C2-59-0081 : G.711u (64

kbps)

59-0081-59-2078 : G.711u (64 kbps)

Call Quality Summary by Call Group - Top 5

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

MO

S

MOS 4.38 4.38 4.38 4.38 4.38

59-0071-P C1-59-0071-P C2 : G.711u

(64 kbps)

59-0071-P C1-59-0032 : G.711u (64

kbps)

59-0071-P C2-59-0032 : G.711u (64

kbps)

59-0071-P C1-59-2078 : G.711u (64

kbps)

59-0071-P C2-59-2078 : G.711u (64

kbps)

Room 0081 and its AP is the source of trouble. All communications between 0081 and other nodes are poor, and they are the only poor links.


WiFi: G711 – 2 Calls: DelayWiFi: G711 – 2 Calls: Delay

The delay varies between 300 and 310 ms, which is on the high side.

Delay Evaluation by Hour

0%

20%

40%

60%

80%

100%

294

298

302

306

310

314

Del

ay (

ms)

Good 67 67 67 67 67 67 67 67 67 65 67 67 67 67 67 67 67 67 67 67 67 67 67 67

Acceptable 0%0% 0% 0% 0% 0% 0%0% 0% 0% 0% 0%0% 0% 0% 0%0% 0% 0% 0% 0%0% 0% 0%

P oor 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33 33

Unavailable 0%0% 0% 0% 0% 0% 0%0% 0% 3% 0% 0%0% 0% 0% 0%0% 0% 0% 0% 0%0% 0% 0%

Delay (ms) 301301301301304302301302308310306303303302302303303300301301301301301301

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM

Room 0081 and its AP is the source of trouble. The delay on those pairs where this link is involved exceeds 800 ms, while the delay on other groups are very low (45 m sec).

Delay Summary by Call Group

0

100

200

300

400

500

600

700

800

900

Del

ay (

ms)

Delay (ms) 826 818 814 812 812 49 47 46 46 45

59-0032-59-0081 : G.711u

59-0071-P C2-59-

0081 :

59-1079-59-0081 : G.711u

59-0081-59-2078 : G.711u

59-0081-59-0071-

P C1 :

59-0032-59-1079 : G.711u

59-0071-P C2-59-

0032 :

59-0032-59-2078 : G.711u

59-0071-P C1-59-0032 :

59-0071-P C1-59-1079 :


On those poor groups the lost data exceeds 20%

Lost Data Evaluation by Hour

0%

20%

40%

60%

80%

100%

5.79%

6.29%

6.79%

7.29%

7.79%

8.29%

Lo

st D

ata

(%)

Good 63 67 67 67 67 67 67 67 67 62 67 67 67 67 67 67 67 67 67 67 67 67 67 67

Acceptable 4%0% 0%0%0% 0% 0%0%0%0% 0% 0%0%0%0% 0% 0%0% 0% 0%0% 0%0% 0%

P oor 33 33 33 33 33 33 33 33 33 36 33 33 33 33 33 33 33 33 33 33 33 33 33 33

Unavailable 0%0% 0%0%0% 0% 0%0%0%3% 0% 0%0%0%0% 0% 0%0% 0% 0%0% 0%0% 0%

Lost Data 6.6 6.6 6.66.6 7.2 6.7 6.7 6.97.6 7.2 7.7 7.2 7.37.1 7.0 7.0 6.96.8 6.6 6.6 6.7 6.66.6 6.5

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM

The lost data varies between 6.6% and 7.7%. In both plots, the high values are noticed in the hours 8:00 – 10:00 AM, indicating a slightly more traffic activity of the WiFi network at this period.

WiFi: G711 – 2 Calls: Lost DataWiFi: G711 – 2 Calls: Lost Data

Lost Data Summary by Call Group

0.00%

5.00%

10.00%

15.00%

20.00%

25.00%

Lo

st D

ata

(%)

Lost Data 22.36% 21.74% 21.19% 20.48% 18.10% 0.03% 0.03% 0.03% 0.02% 0.01%

59-0032-59-0081 : G.711u

59-1079-59-0081 : G.711u

59-0081-59-0071-

P C1 :

59-0071-P C2-59-

0081 :

59-0081-59-2078 : G.711u

59-0032-59-1079 : G.711u

59-2078-59-1079 : G.711u

59-0071-P C2-59-

1079 :

59-0071-P C1-59-1079 :

59-0032-59-2078 : G.711u


For the first group the quality is maintained well throughout the call duration, while the quality is poor throughout the duration of second call, with short intervals when the communication is lost.

Zooming in to the call level, the figure shows three random calls for a good group, while second figure shows three random calls for a poor group.

WiFi: G711 – 2 Calls: Sample Call QualityWiFi: G711 – 2 Calls: Sample Call Quality



Figure shows the overall statistics of call quality. The Figure shows that the call quality is poor most of the time (75%). The quality is acceptable for 14% of the time, and good for 10% of the time.

Number of nodes 6

Number of Links 15







Good10%

Acceptable14%

Poor75%

Unavailable1%

Good

Acceptable

Poor

Unavailable


WiFi Assessment Results WiFi Assessment Results G711 – 4 Calls: Factors Affecting MOSG711 – 4 Calls: Factors Affecting MOS

The percentage effect of the three performance factors is shown in Figure below. Here we can clearly see that the source of poor quality is lost data (52 %) and delay (44%). The effect of jitter is marginal (4%) therefore no further analysis of jitter is carried out.

Factors Affecting Call Quality

Delay44%

Jitter4%

Lost Data52%

Delay

Jitter

Lost Data

Codec




1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

MO

S

MOS 3.98 3.89 3.55 3.25 2.96

59-0032-59-2078 : G.711u (64 kbps)

59-2078-59-1079 : G.711u (64 kbps)

59-0032-59-1079 : G.711u (64 kbps)

59-0071-P C2-59-2078 : G.711u (64

kbps)

59-0071-P C2-59-0032 : G.711u (64

kbps)


1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

MO

S

MOS 1.20 1.20 1.16 1.04 1.03

59-0032-59-0081 : G.711u (64 kbps)

59-0081-59-2078 : G.711u (64 kbps)

59-1079-59-0081 : G.711u (64 kbps)

59-0081-59-0071-P C1 : G.711u (64

kbps)

59-0071-P C2-59-0081 : G.711u (64

kbps)


WiFi: G711 – 4 Calls: Call Quality by HourWiFi: G711 – 4 Calls: Call Quality by Hour

The Figure shows the effect of the data traffic on the quality of IPT traffic (MOS ~ 2.7 in light traffic hours 11 pm – 7 am) (MOS ~ 2.1 in Busy Hour (BH) 8am – 9 pm)

Call Quality Evaluation by Hour

0%

20%

40%

60%

80%

100%

1.00

1.70

2.40

3.10

3.80

4.50

MO

S

Good 6% 12%8% 18%14%11%21%23%8% 11%10%10%3% 9% 7% 7% 5% 9% 5% 8% 8% 7% 11% 11%

Acceptable 23%21%20%22%27%20%22%22%13%6% 8% 9% 11% 9% 9% 10%12%7% 10%11% 9% 11%14%22%

P oor 70%66%70%59%59%69%57%55%78%82%81%79%86%83%85%78%83%84%86%81%82%79%74%66%

Unavailable 1% 1% 2% 1% 1% 0% 0% 0% 1% 0% 1% 2% 0% 0% 0% 6% 1% 1% 0% 0% 2% 3% 0% 0%

M OS 2.6 2.7 2.6 2.8 2.8 2.7 2.8 2.8 2.3 2.132.16 2.2 2.0 2.172.13 2.112.122.13 2.0 2.10 2.112.12 2.4 2.71

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM


WiFi: G711 – 4 Calls: Delay by HourWiFi: G711 – 4 Calls: Delay by Hour

Figure shows that the delay has been always excessive (average delay over 600 ms and in busy hours it even approaches 740 ms).


0%

20%

40%

60%

80%

100%

0

160

320

480

640

800

Del

ay (

ms)

Good 28 33 27 38 33 25 43 43 26 29 27 30 17%25 20 19%18% 25 16%23 22 20 28 33

Acceptable 36 31% 35 28 32 42 22 22 31%17%23 24 36 30 33 25 30 25 31%25 24 27 30 31%

P oor 35 34 36 34 34 33 36 35 43 54 49 44 47 45 47 50 51% 50 53 52 53 50 43 36

Unavailable 1% 1% 2% 1% 1% 0% 0% 0% 1% 0% 1% 2% 0% 0% 0% 6% 1% 1% 0% 0% 2% 3% 0% 0%

Delay (ms) 637625655608617642615601653720687666697673690731721697717729733724678630

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM


WiFi: G711 – 4 Calls: Lost Data of Best and Worst Call by HourWiFi: G711 – 4 Calls: Lost Data of Best and Worst Call by Hour

The figure shows the lost data evaluation, the average percentage of lost data has been above 16%, and exceeding 28% during Busy hours.


0%

20%

40%

60%

80%

100%

0.00%

7.00%

14.00%

21.00%

28.00%

35.00%

Lo

st D

ata

(%)

Good 0% 2%0% 1% 1% 1% 2% 5%2% 3%5% 2% 0%5% 1% 1% 3%4% 1% 1% 2%1% 0%0%

Acceptable 0% 0%0% 1% 1% 1% 1% 1% 1% 2%0% 1% 1% 1% 3%3% 2%1% 1% 2% 2%2% 1% 0%

P oor 99 97 98 97 96 97 97 95 96 95 94 95 99 94 96 90 95 94 99 97 94 94 99 100

Unavailable 1% 1% 2% 1% 1% 0%0% 0%1% 0%1% 2% 0%0% 0%6% 1% 1% 0%0% 2%3% 0%0%

Lost Data 19. 18. 18. 17. 17. 17. 16. 16. 25. 27.28. 26. 29.27. 28.28. 28.28. 28.26. 27.27. 21. 18.

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM


WiFi: G711 – 4 Calls: Sample Call QualityWiFi: G711 – 4 Calls: Sample Call Quality

Finally, we show through-call evaluation of Call Quality and corresponding Lost Data of some selected calls on the best link. Two such calls are depicted in figures.

It is interesting to show that while a high MOS is maintained throughout the call duration there are intermittent periods when call quality drops to a poor level. These are the periods when the link suffers from large packet loss.


WiFi Assessment Results WiFi Assessment Results G723 – 1 Call: Call Quality (MOS)G723 – 1 Call: Call Quality (MOS)

The performance is always acceptable. It should be noted that “acceptable” is the best quality that can be obtained for G723.


Acceptable100%

Poor< 1%

Unavailable< 1%

Good

Acceptable

Poor

Unavailable

Number of nodes 6

Number of Links 15







WiFi Assessment Results WiFi Assessment Results G723 – 1 Call: Factors Affecting MOSG723 – 1 Call: Factors Affecting MOS

Therefore, that “acceptability” of the quality of the IPT call is mainly due to codec. The average delay is in the range of 130 ms. This is higher that the average delay for the G711 codec under same traffic load, due to the extra processing time for compression.

Factors Affecting Call Quality

Codec93%

Delay7%

Jitter< 1%

Lost Data< 1%

Delay

Jitter

Lost Data

Codec



By increasing the number of calls to 4 between each pair, the quality gets severely affected. Figure shows that only 28% of the calls are now acceptable.

Number of nodes 6

Number of Links 15


Number of concurrent calls per nodes 5 x 4 = 20





Acceptable28%

Poor72%

Unavailable< 1%

Good

Acceptable

Poor

Unavailable



The pattern of variation of performance between groups is very much similar to the 2-call case of G-711.


1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

MO

S

MOS 3.60 3.59 3.59 3.58 3.56

59-0071-P C2-59-2078 : G.723.1-

ACELP (5.3 kbps)

59-0071-P C2-59-1079 : G.723.1-

ACELP (5.3 kbps)

59-0071-P C1-59-2078 : G.723.1-

ACELP (5.3 kbps)

59-0071-P C1-59-1079 : G.723.1-

ACELP (5.3 kbps)

59-2078-59-1079 : G.723.1-ACELP

(5.3 kbps)


1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

MO

S

MOS 1.28 1.33 1.36 1.38 1.45

59-0032-59-0081 : G.723.1-ACELP

(5.3 kbps)

59-1079-59-0081 : G.723.1-ACELP

(5.3 kbps)

59-0071-P C2-59-0081 : G.723.1-

ACELP (5.3 kbps)

59-0071-P C1-59-0081 : G.723.1-

ACELP (5.3 kbps)

59-0081-59-2078 : G.723.1-ACELP

(5.3 kbps)

Namely, the groups are classified in two sets; always acceptable (MOS=3.6), and always poor (MOS=1.4).


WiFi: G723 – 4 Calls: Call Quality of Best and Worst Group by HourWiFi: G723 – 4 Calls: Call Quality of Best and Worst Group by Hour

Since data rate of G723 is low, there does not seem to be a Busy Hour effect on the MOS for either set.


0%

20%

40%

60%

80%

100%

1.00

1.70

2.40

3.10

3.80

4.50

MO

S

Good 0%0% 0% 0% 0% 0%0% 0% 0% 0%0% 0% 0% 0%0% 0% 0% 0%0% 0% 0%0% 0% 0%

Acceptable 63 71%78 71%56 71%50 82 69 79 81%75 75 71%59 71%69 75 84 29 69 71% 78 79

P oor 38 29 22 29 44 29 50 11%31%21%19%25 25 29 41%29 31% 25 16%71%31%29 22 21%

Unavailable 0%0% 0% 0% 0% 0%0% 7% 0% 0%0% 0% 0% 0%0% 0% 0% 0%0% 0% 0%0% 0% 0%

MOS 3.6 3.53.613.5 3.6 3.6 3.5 3.6 3.613.6 3.6 3.6 3.53.613.5 3.5 3.5 3.6 3.6 3.5 3.6 3.5 3.613.6

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM


0%

20%

40%

60%

80%

100%

1.00

1.70

2.40

3.10

3.80

4.50

MO

S

Good 0%0% 0% 0% 0% 0%0% 0% 0% 0%0% 0% 0% 0%0% 0% 0% 0%0% 0% 0%0% 0% 0%

Acceptable 0%0% 0% 0% 0% 0%0% 0% 0% 0%0% 0% 0% 0%0% 0% 0% 0%0% 0% 0%0% 0% 0%

P oor 100100100 100100100100100 100100100100 100100100100100 100100100100100 100 86

Unavailable 0%0% 0% 0% 0% 0%0% 0% 0% 0%0% 0% 0% 0%0% 0% 0% 0%0% 0% 0%0% 0%14%

MOS 1.161.151.241.271.291.481.261.241.231.281.291.351.371.261.251.241.251.341.281.261.251.381.281.23

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM


The call quality within the duration of the call is maintained almost constant, for "acceptable groups" as well as poor groups.

WiFi: G723 – 4 Calls: Call Inside DetailsWiFi: G723 – 4 Calls: Call Inside Details


University ADSL NetworkUniversity ADSL Network

ADSL service provided on campus is at G-Lite rate (1.5 Mbps downlink and 0.5 Mbps uplink).

The ADSL system of university is of modular nature. There are total of 10 DSLAMs and each DSLAM has a capacity of approximately 100 ADSL lines. Each DSLAM uplink supports 100 Mbps and is connected to the layer-2 switch.

LAN

UTILSTAT

DUPLEXSPEED

SYSTEMRPS

CATALYST 35503

4

5

6

7

8

9

10

11

12

1

2

15

16

17

18

19

20

21

22

23

24

13

14

1 2

DSLAM 1

Layer-2 Switch

Computer

DSLAM 2 DSLAM 3

Computer Computer Computer Computer Computer Computer


University ADSL Assessment DesignUniversity ADSL Assessment Design

LAN

UTILSTAT

DUPLEXSPEED

SYSTEMRPS

CATALYST 35503

4

5

6

7

8

9

10

11

12

1

2

15

16

17

18

19

20

21

22

23

24

13

14

1 2

DSLAM 1

Layer-2 Switch

DSLAM 1-1

DSLAM 8

DSLAM 1-2 DSLAM 1-3 DSLAM 8-1

DSLAM 8-2

Local Loop

Local Loop

Local Loop

DSLAM 1-1

DSLAM 1-2 DSLAM 1-3

DSLAM 8-1 DSLAM 8-2

ADSL Assessment Test Physical Connectivity

ADSL Assessment Test Logical Connectivity


ADSL Assessment ResultsADSL Assessment Results

ADSL Assessment Parameters used for VoIP Test

For G711 codec: 100% good result, Delay < 62 ms, Jitter and Lost Data almost negligible.

For G723 codec: Similar results, slightly lower MOS and higher delay.

Number of nodes 5

Number of Links 10







ADSL Assessment ResultsADSL Assessment ResultsCall Quality (MOS) for G711Call Quality (MOS) for G711


Good100%

Good

Acceptable

Poor

Unavailable


0%

20%

40%

60%

80%

100%

1.00

1.70

2.40

3.10

3.80

4.50

MO

S

Good 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100

Acceptable 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

P oor 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Unavailable 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

M OS 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM

Call Quality Summary by Call Group

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

MO

S

M OS 4.38 4.37 4.37 4.37 4.37 4.37 4.37 4.37 4.37 4.37

DSLAM 1-2-

DSLAM 8-1 :

DSLAM 1-3-

DSLAM 8-1 :

DSLAM 1-2-

DSLAM 8-2 :

DSLAM 1-1-

DSLAM 1-2 :

DSLAM 8-2-

DSLAM 1-3 :

DSLAM 1-1-

DSLAM 8-1 :

DSLAM 1-2-

DSLAM 1-3 :

DSLAM 1-1-

DSLAM 1-3 :

DSLAM 1-1-

DSLAM 8-2 :

DSLAM 8-1-

DSLAM 8-2 :


ADSL Assessment ADSL Assessment ResultsResults

Delay and Lost Data Delay and Lost Data for G711for G711


0%

20%

40%

60%

80%

100%

59

60

61

62

63

64

Del

ay (

ms)

Good 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100

Acceptable 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

P oor 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Unavailable 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Delay (ms) 61 62 61 61 61 62 60 61 61 60 60 62 61 61 61 61 62 62 61 62 61 61 61 61

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM


0%

20%

40%

60%

80%

100%

0.00%

0.01%

0.02%

0.03%

0.04%

0.05%

Lo

st D

ata

(%)

Good 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100

Acceptable 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

P oor 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Unavailable 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Lost Data .01%.01%.01%.01%.01%.01%.01%.01%.01%.01%.02 .03 .03 .03 .04 .04 .02 .01%.01%.01%.01%.01%.01%.01%

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM


ADSL Assessment ResultsADSL Assessment ResultsCall Quality (MOS) for G723Call Quality (MOS) for G723


Acceptable99%

Poor1%

Unavailable< 1%

Good

Acceptable

Poor

Unavailable

Factors Affecting Call QualityDelay9%

Codec91%

Jitter< 1%

Lost Data< 1%

Delay

Jitter

Lost Data

Codec



Call Quality (MOS) by Call Quality (MOS) by Hour and by Group, Hour and by Group,

for G723for G723


0%

20%

40%

60%

80%

100%

1.00

1.70

2.40

3.10

3.80

4.50

MO

S

Good 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Acceptable 100 100 100 100 100 100 100 100 100 100 100 100 96%97%95%100 99%100 100 87%98%100 100 100

P oor 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 4% 3% 0% 0% 1% 0% 0% 13%3% 0% 0% 0%

Unavailable 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 5% 0% 0% 0% 0% 0% 0% 0% 0% 0%

M OS 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM

Call Quality Summary by Call Group

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

MO

S

M OS 3.63 3.63 3.62 3.62 3.62 3.62 3.62 3.62 3.62 3.62

DSLAM 1-2-

DSLAM 8-2 :

DSLAM 1-2-

DSLAM 8-1 :

DSLAM 8-2-

DSLAM 1-3 :

DSLAM 1-1-

DSLAM 1-3 :

DSLAM 1-3-

DSLAM 8-1 :

DSLAM 1-1-

DSLAM 1-2 :

DSLAM 1-2-

DSLAM 1-3 :

DSLAM 8-1-

DSLAM 8-2 :

DSLAM 1-1-

DSLAM 8-1 :

DSLAM 1-1-

DSLAM 8-2 :



Delay and Lost Data Delay and Lost Data for G723for G723


0%

20%

40%

60%

80%

100%

143

145

147

149

151

153

Del

ay (

ms)

Good 87%89%78%69%71%78%82%83%86%89%86%87%84%86%74%71%78%84%85%71%71%71%67%71%

Acceptable 13%11%23%31%29%22%18%18%14%11% 14%13%16%14%21%29%23%16%15%29%29%29%33%29%

P oor 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Unavailable 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 5% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Delay (ms) 145 145 146 146 147 146 146 146 145 145 146 146 146 146 146 147 145 145 145 145 146 147 148 146

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM


0%

20%

40%

60%

80%

100%

0.00%

0.01%

0.02%

0.03%

0.04%

0.05%

Lo

st D

ata

(%)

Good 100 100 100 100 100 100 100 100 100 100 100 100 100 10095%100 100 100 100 100 100 100 100 100

Acceptable 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

P oor 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Unavailable 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 5% 0% 0% 0% 0% 0% 0% 0% 0% 0%

Lost Data .01%.01%.01%.01%.01%.01%.01%.01%.01%.01%.01%.01%.01%.01%.01%.01%.01%.01%.01%.03 .01%.01%.01%.01%

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM


Conclusions: LANConclusions: LAN

The performance of IPT over LAN was perfect, even when an unrealistically exaggerated traffic was assumed (50% of users are busy on call).

The delay was at its minimum value (~ 40ms for G711 and ~130 ms for G723), and lost data and jitter loss was close to zero.

The MOS parameter was always approaching the maximum possible for each of the two codecs i.e. 4.38 for G711 and 3.65 for G723.

No noticeable variation on the call quality was observed during the span of 7 days nor during the span of the whole day.

No difference in performance may be attributed to the specific locations of the nodes or Busy Hour of data traffic.


Conclusions on ADSLConclusions on ADSL Although the ADSL link is nowhere close to the

capacity of LAN, it is a dedicated link per house. For G711 codec call quality remained at maximum

possible throughout the duration of test. The delay was found to be well within the limits,

and jitter and lost data were almost negligible. All links behaved equally well without any effects

of local loop and of intra-DSALM or inter-DSLAM calls.

The results for the G 723 codec were similarly perfect, taking into considerations the slightly lower MOS value and slightly high delay due to the use of this compressed codec.

The DSLAM network can safely support maximum number of realistically expected calls from any typical house.


ConclusionConclusion

Lowe traffic: The performance seems to be pretty good for more than

99% of the calls. The average delay was always below 45 ms Lost data was negligible (less than 0.03%). Moreover, all links performed equally well.

Medium Traffic: 33% of the calls became poor. High variation in call quality between different pairs of

nodes, some being consistently “good” and others being consistently “poor”.

By examining the poor links, we found one node common to all.

The channel between that node and the nearest Access Point is poor, therefore affecting all the communications where this node is involved.


ConclusionConclusion

High Traffic call quality became poor most of the time (75%). we started to notice the effect of Busy Hours of

data traffic on IPT quality. The MOS of calls between 9 pm-8 am were

found to be 30% above that for calls between 8 am – 9 pm.

G723 results was similar in pattern to those of G711 with two differences: The best quality for this codec is “acceptable”

rather than “good”. It does not get much affected with data traffic

intensity.


Thank You

performance evaluation of ip telephony over university network a project funded by university fast...

Documents

voip testevaluation

university networksassessment

university networksvoice

university networksperformance

university networkswhat

university networkss

university networksbldg

ip voip assessment