1. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. Presentation Contents BluetoothChallengesDevelopmentResultConclusion ChallengesDevelopmentResultConclusion A Presentation of CEG 499 project Supervisor : Dr Nova Ahmed Assistant Professor, Department of EECS, North South University. Presented by : M Rubaiyat Bin Sattar ID Number # 061 – 671 - 044

2. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. Presentation Contents BluetoothChallengesDevelopmentResultConclusion ChallengesDevelopmentResultConclusion A Presentation of CEG 499 project Supervisor : Dr Nova Ahmed Assistant Professor, Department of EECS, North South University. Presented by : M Rubaiyat Bin Sattar ID Number # 061 – 671 - 044

3. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion What is Bluetooth ? ● Tenth-century Danish viking & king Harald Blatand (Bluetooth) ● Bluetooth - radio technology- frequency-hopping spread spectrum ● ISM band: 2.4 GHz. ● Short-range, Low cost, Low power connectivity solution Application of Bluetooth Special Interest Group (SIG) ● Bluetooth first developed in Ericsson’s research laboratory 1994. ● SIG was formed in 1998 to promote the technology ● IEEE 802.15 is the standardization of Bluetooth ● v2.1+EDR adopted in July 2007 – Transmission rate 3Mbits/s ● v3.0 + HS adopted in April 2009 –transmission rate 24Mbit/s ● In July 2010 SIG reveled Bluetooth v4, High speed based on Wi-Fi ● Data transfer, audio streaming, GPS navigation,video streaming. ● Video streaming – Spy cam, Monitoring system, Sharing movie ● In general - range is 10 meter

4. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Bluetooth Protocol Stack Link Management Protocol (LMP) is responsible for radio link set up between nodes by the baseband layer. Other responsibility - manage piconets, monitors service quality. The Logical Link Control and Adaptation Protocol (L2CAP) receives application data and adapts it to the Bluetooth format. √ Maintains a packet queue, √ Essential for streaming application The service Discovery protocol (SDP) is used for investigation of connection between devices. The LMP uses the service Discovery protocol (SDP) to find out what service is available

5. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Bluetooth Protocol Stack The baseband layer maintains Synchronous Connection-Oriented (SCO) links for voice & Asynchronous Connectionless (ACL) links for data. It controls and send data over the radio link Bluetooth Network Encapsulation Protocol (BNEP) layer provided a consistent interface to (LL), transfer IP packets in PAN Profile via L2CAP channel, run PPP and emulates Ethernet HCI is the dividing line between software and hardware. The L2CAP and layers above it are currently implemented in software, and the LMP and lower layers are in hardware. The BTnode structure for simulation (video Streaming) - where upper part is default ns-2 agent and middle is the bluetooth extension.

6. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Bluetooth Protocol Stack Alternative controller besides EDR, √ consists three layer :- (1) Protocol Adaptation layer (2) alternative mac protocol (3) alternative Physical layer

7. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Connection Establishment 3 steps : INQUIRY -> PAGE -> CONNECTION -First standby mode and listen for message over 32 hop frequency. -In a new environment, the device automatically initiates an inquiry to find an access point. All nearby access points respond with their addresses, and the device picks access point. Inquiry Search Inquiry Scan

8. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Connection Establishment 3 steps : INQUIRY -> PAGE -> CONNECTION - If inquiry is successful -Paging procedure synchronizes the device with access point. -Link Manager Protocol (LMP) establishes a link with the access point -LMP uses SDP for available service information & create L2CAP channel. Page Scan Inquiry Scan Page

9. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Connection Establishment 3 steps : INQUIRY -> PAGE -> CONNECTION -In active state master and slave listen, transmit and receive data - Point to be noted, in Inquiry state if there is no reply from a devices, then it stay as undiscoverable. Slave Inquiry Scan Master

10. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion What is Piconet ? Piconet refers following key points: 1. Short range 2. Master - Slave 3. Frequency Hopping 4. Master + n slave ;n ≤ 7 5. Additional slaves- parked ●Standard piconet -7 slaves ● Up to 255 parked slaves ● Active devices are assigned a 3- bit active member address ● Parked devices are assigned an 8- bit parked member address ● Standby devices do not need an address

11. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. Presentation Contents BluetoothChallengesDevelopmentResultConclusion ChallengesDevelopmentResultConclusion Video files & other tools http://www.vsebt.okzbd.com

12. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Video Streaming in Bluetooth : ● (LAN) or (Wi-Fi) - has band-width, delay and loss requirements ● Bluetooth link is little bit challenging ; many potential reason : □ Low bandwidth, out of range device, time –varying feature and interference with other devices or external sources Bluetooth Simulation in ns-2 : ● BlueHoc (2001) - Developed at IBM – now out dated ● UCBT (2005)- Developed at University of Cincinnati - support v2+EDR ● HSBT (2010 NOV) - Developed at Cairo University – Support latest Bluetooth v3+HS ● However – Works only in ns-2.29, need native linux machine. -Very Hard to simulate in modern machine without significant effort ; such as downgrading the compiler

13. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Insufficient Documentation : ● Working with ns-2 is hard where there is no proper documentation ● One have to create their own documentation for works ● Question : is it possible to do video streaming in BT node ? Information Existing video streaming schemes in “Wired” and “Wi-Fi” Ex :China-Henry, frank They  Integrated ns2 for streaming & evaluation in wired and wi-fi Compare with Bluetooth related papers/survey for video streaming over Bluetooth network. Ex : M.H.Chia, Salim Beg, Wang Xiaohang Findings : ● Streaming Via IP -Some connection with existing simulation. -IP ?? > By BNEP, L2CAP ● MPEG-4 Video Codec

14. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Machine Preparation – Environment Settings : Bluetooth Library fixing for ns-2 Integration of Evaluation method ns-2.29 Bug Fixing Rtptools in cygwin for evaluation Evalvid Tools in Cygwin for evaluation Machine prepared for simulation AWK command Appropriate Video Compression format VSEBT An Adaptive Approach for V ideo S treaming and E valuation Over B lue t ooth Network

15. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. Presentation Contents BluetoothChallengesDevelopmentResultConclusion ChallengesDevelopmentResultConclusion http://www.vsebt.okzbd.com Video files & other tools

16. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion VSEBT SORRY CURRENTLY NOT ALLOWED TO SHOW DEVELOPMENT PART

17. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. Presentation Contents BluetoothChallengesDevelopmentResultConclusion ChallengesDevelopmentResultConclusion Video files & other tools http://www.vsebt.okzbd.com

18. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Video Files and Extra tools Video files & other tools www.vsebt.okzbd.com

19. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. Presentation Contents BluetoothChallengesDevelopmentResultConclusion ChallengesDevelopmentResultConclusion http://www.vsebt.okzbd.com Video files & other tools

20. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Performance Parameter : ● Delay :Time taker for a packet,transmit from source to destination Delay :End time – Start Time ● Jitter : Represents variance of delay Jitter = {End to End Delay (j) – End to End Delay (i)} / (j-i), where j>i ● Throughput : Defines the Number of bits from (A to B / Observation) Throughput for each packet = {(CBR packet size in Bytes * 8 ) / End to End Delay /1000} (kbps) ● Loss : No, as we follow time manner strictly

21. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis ffmpeg_EDR (Total Packet sent 569) Node Data RateAverage DelayDelivery Ratio 113171.000000 (105368/8.000000)0.654149 (97.468215/149)1.000000 (1- 0/569) 213036.125000 (104289/8.000000)0.668224 (98.897152/148)1.000000 (1- 0/569) 312882.875000 (103063/8.000000)0.714865 (104.370289/146)1.000000 (1- 0/569) 412739.000000 (101912/8.000000)0.780605 (112.407126/144)1.000000 (1- 0/569) 514250.000000 (114000/8.000000)0.405847 (63.717970/157)1.000000 (1- 0/569) 613305.875000 (106447/8.000000)0.620212 (93.031778/150)1.000000 (1- 0/569) 713172.000000 (105368/8.000000)0.643671 (95.906965/149)1.000000 (1- 0/569) 514250.000000 (114000/8.000000)0.405847 (63.717970/157)1.000000 (1- 0/569) Data rate : 14250.000000 ( bytes ) [ total received bytes / data stream (114000/8.000000) ] set-statist 7 15 1 adjust l2cap hdr [represents collecting statistic {End(15) – Begin (7)} /steps (1) = 8, the period of statistics or data stream time ] Average Delay : 0.405847 (s) [Total Delay for burst / Total hops (63.717970/157 ) ] AODV routing protocol - determine the hopping Delay Ratio: 1.000000 (1- 0/569) [1- Lost packets / send packets ) ] Total of 569 packets send by ffmpeg

22. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis X264_EDR (Total Packet sent 556) Node Data RateAverage DelayDelivery Ratio 112137.625000 (97101/8.000000)0.595006 (85.085839/143)1.000000 (1- 0/556) 212137.625000 (97101/8.000000)0.597427 (85.432089/143)1.000000 (1- 0/556) 312040.500000 (96324/8.000000)0.620612 (88.126857/142)1.000000 (1- 0/556) 412040.500000 (96324/8.000000)0.633261 (89.923107/142)1.000000 (1- 0/556) 512015.625000 (96125/8.000000)0.638100 (89.972166/141)1.000000 (1- 0/556) 613265.875000 (106127/8.000000)0.286577 (44.992525/157)1.000000 (1- 0/556) 712280.875000 (98247/8.000000)0.538133 (79.105536/147)1.000000 (1- 0/556) 512015.625000 (96125/8.000000)0.638100 (89.972166/141)1.000000 (1- 0/556) 514250.000000 (114000/8.000000)0.405847 (63.717970/157)1.000000 (1- 0/569)

23. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis Xvid_EDR (Total Packet sent 856) Nod e Data RateAverage DelayDelivery Ratio 114422.125000 (115377/8.00000)1.480219 (182.066989/123)1.000000 (1 -0/856) 214422.125000 (115377/8.00000)1.496256 (184.039489/123)1.000000 (1 -0/856) 314084.125000 (112673/8.00000)1.509867 (181.184077/120)1.000000 (1 -0/856) 413813.375000 (110515/8.00000)1.556477 (183.664253/118)1.000000 (1 -0/856) 515512.500000 (124100/8.00000)1.308045 (172.661882/132)1.000000 (1 -0/856) 614557.000000 (116456/8.00000)1.452801 (180.147276/124)1.000000 (1 -0/856) 714422.125000 (115377/8.00000)1.467587 (180.513239/123)1.000000 (1 -0/856) 515512.500000 (124100/8.00000)1.308045 (172.661882/132)1.000000 (1 -0/856) 512015.625000 (96125/8.000000)0.638100 (89.972166/141)1.000000 (1- 0/556) 514250.000000 (114000/8.000000)0.405847 (63.717970/157)1.000000 (1- 0/569)

24. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis 515512.500000 (124100/8.00000)1.308045 (172.661882/132)1.000000 (1 -0/856) 512015.625000 (96125/8.000000)0.638100 (89.972166/141)1.000000 (1- 0/556) 514250.000000 (114000/8.000000)0.405847 (63.717970/157)1.000000 (1- 0/569) 0.405847 (63.717970/157) ffmpeg_EDR (average delay) 0.638100 (89.972166/141) x264_EDR (average delay) 1.308045 (172.661882/132) Xvid_EDR (average delay) 00.065330 10.070330 20.075330 30.080330 40.085330 50.090330 ……………………………. 5643.856445 5653.859070 5663.903811 5673.833695 5683.843010 00.032330 10.037330 20.042330 30.044598 40.016466 50.236756 ……………………………. ……………………………. 5514.044206 5523.961486 5533.972132 5543.996185 5554.000924 00.059330 10.064330 20.069330 30.074330 40.079330 50.084330 ……………………………. ……………………………. 85114.112449 85214.122622 85314.171409 85414.206409 85514.217985

25. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis

26. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis ffmpeg_HS (Total Packet sent 569) NodeData RateAverage DelayDelivery Ratio 119759.875000 (158079/8.000000)0.000445 (0.096508/217)1.000000 (1- 0/569) 219759.875000 (158079/8.000000)0.001123 (0.243630/217)1.000000 (1- 0/569) 319759.875000 (158079/8.000000)0.001801 (0.390763/217)1.000000 (1- 0/559) 419759.875000 (158079/8.000000)0.002479 (0.537913/217)1.000000 (1 -0/559) 519759.875000 (158079/8.000000) 0.003157 (0.685070/217) 1.000000 (1 -0/559) 623867.875000 (190943/8.000000)0.003363 (0.837374/249)1.000000 (1 - 0/601) 723867.875000 (190943/8.000000)0.003937 (0.980428/249)1.000000 (1- 0/601) X264_HS (Total Packet sent 556) NodeData RateAverage DelayDelivery Ratio 115955.000000 (127640/8.000000)0.000278 (0.051691/186)1.000000 (1- 0/556) 215955.000000 (127640/8.000000)0.000584 (0.108554/186)1.000000 (1- 0/556) 315955.000000 (127640/8.000000)0.000889 (0.165426/186)1.000000 (1- 0/556) 415955.000000 (127640/8.000000)0.001195 (0.222306/186)1.000000 (1- 0/556) 515955.000000 (127640/8.000000) 0.001501 (0.279190/186 ) 1.000000 (1- 0/556) 620063.000000 (160504/8.000000)0.001544 (0.336597/218)1.000000 (1- 0/588) 720063.000000 (160504/8.000000)0.001801 (0.392541/218)1.000000 (1- 0/588) Xvid_HS (Total Packet sent 856) NodeData RateAverage DelayDelivery Ratio 140179.250000 (321434/8.000000)0.001780 (0.635539/357)1.000000 (1- 0/856) 240179.250000 (321434/8.000000)0.002620 (0.935359/357)1.000000 (1- 0/856) 340179.250000 (321434/8.000000)0.003460 (1.235191/357)1.000000 (1- 0/856) 440179.250000 (321434/8.000000)0.004300 (1.535052/357)1.000000 (1- 0/856) 540179.250000 (321434/8.000000) 0.005140 (1.834931/357) 1.000000 (1- 0/856) 644287.250000 (354298/8.000000)0.005512 (2.144318/389)1.000000 (1- 0/888) 744287.250000 (354298/8.000000)0.006275 (2.440909/389)1.000000 (1- 0/888) Peak delay 17ms, Xvid – less fluctuation Compare to others

27. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis Peak Jitter at 225ms for x264 format and in average 60ms

28. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis Below 10ms

29. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis X264 – 290 kbps ; Xvid & ffmpeg - 40kbps & 37kbps respectively

30. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis x264 & ffmpeg peak at near 30000 kbps, after 17s later Xvid also touch peak value.

31. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis No big difference -18ms- but invalid packet is observed in output flow ffmpeg_HS_with Traffic (Total Packet sent 569) NodeData RateAverage DelayDelivery Ratio 147360.500000 (378884/8.000000)0.000288 (0.124268/432)1.000000 (1 - 0/885) 247360.500000 (378884/8.000000)0.000643 (0.277643/432)1.000000 (1 - 0/885) 347360.500000 (378884/8.000000)0.000997 (0.430906/432)1.000000 (1 - 0/885) 447360.500000 (378884/8.000000)0.001351 (0.583479/432)1.000000 (1 - 0/885) 547360.500000 (378884/8.000000)0.001708 (0.738055/432)1.000000 (1 - 0/885) 647360.500000 (378884/8.000000)0.002063 (0.891398/432)1.000000 (1 - 0/935) 747488.875000 (379911/8.000000)0.002414 (1.045257/433)1.000000 (1 - 0/936)

32. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis No big difference -17ms - but invalid packet is observed in output flow Xvid_HS_ with Traffic ((Total Packet sent 856) NodeData RateAverage DelayDelivery Ratio 167779.875000 (542239/8.000000)0.001287 (0.736427/572)1.000000 (1 - 0/1172) 267779.875000 (542239/8.000000)0.001824 (1.043099/572)1.000000 (1 - 0/1172) 367779.875000 (542239/8.000000)0.002360 (1.349661/572)1.000000 (1 - 0/1172) 467779.875000 (542239/8.000000)0.002894 (1.655550/572)1.000000 (1 - 0/1172) 567779.875000 (542239/8.000000)0.003433 (1.963446/572)1.000000 (1 - 0/1172) 667779.875000 (542239/8.000000)0.003969 (2.270099/572)1.000000 (1 - 0/1222) 767908.250000 (543266/8.000000)0.004498 (2.577290/573)1.000000 (1 - 0/1223)

33. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis (VSEBT_Rtp) Delay increase gradually from 0 to 37 seconds Delay record less than 1ms in HS system ( constant )Extraordinary performance of HS is ultimately Incomparable With EDR

34. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis (VSEBT_Rtp) Peak at 53ms when system is EDR and Constant Zero when system is HS

35. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis (VSEBT_Rtp) Peak at 130 Kbps then gradually decrease to 1kbps, at beginning node 4 creates peak & 6 low

36. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Graphs and Analysis (VSEBT_Rtp) High Throughput node 1 – 109000 kbps and Low throughput node 7 – 20000kbps. [ Constant]

37. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Possibly Live test and graphs analysis Test between two HP laptop : - Support EDR 2.1 functionality -a assumption that unicast streaming in EDR (ns-2) gives the same output.

38. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Possibly Live test and graphs analysis

39. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Possibly Live test and graphs analysis Peak Delay 345ms and most of the time delay range is in between 20ms & 260 msIn some point jitter goes to 250 ms and rest of the cases stay in acceptable range Finally Throughput where peak at 755 kbps and low value at 11kbps. We assume our experimental live streaming test is very similar like the output data.

40. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. Presentation Contents BluetoothChallengesDevelopmentResultConclusion ChallengesDevelopmentResultConclusion Video files & other tools http://www.vsebt.rangan.nopayhost.com

41. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion We have developed - ●Method for video streaming and evaluation over -Bluetooth (v2.1 & v3) -in maximum possible salves (7) -which support any video duration ●Two frameworks - can be applied over upcoming Bluetooth specification (v4) Findings : √Encoding method is extremely important – √ The packet size & type 3-DH5 It can be believe that this research work is the first work with High speed Bluetooth connection as it is adopted very recently

42. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Further research- we consider experimenting with scatternet topology and to supports any video format To face this challenge – Critical implementation methods (ex: new protocol design, node formation) have to be addressed for realistic video transmission and evaluation. However, if we only concern with piconet another new topology can be created. If we can merge master of piconet with Wifi Router. Wifi Cum Bluetooth ( WB )

43. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. ChallengesDevelopmentResultConclusion Wi-fi Cum Bluetooth ( Future work ) High CostLow Cost Conclusion

44. Bluetooth V SEBT An Adaptive Approach for Video Streaming and Evaluation Over Bluetooth Network. Presentation Contents BluetoothChallengesDevelopmentResultConclusion ChallengesDevelopmentResultConclusion Questions Video files & other tools www.vsebt.okzbdcom