1. 1 MPEG Streaming over Mobile Internet Kyunghee Lee and Myungchul Kim {leekhe, mckim}@icu.ac.kr

2. 2 Contents Introduction Related Work Proposed Mechanism System Design Testbed Configuration Experiments Performance Evaluation Conclusions References

3. 3 Introduction General multimedia data characteristics –Intolerant to delay and jitter variance –Error-sensitive Characteristics of mobile Internet –Frequent routing path changes due to handoffs –Higher error rate in wireless link Effects on streaming multimedia data in mobile Internet –Handoff delay –Re-routing toward congested network  delay increment –Higher packet loss probability due to mobility  Significant quality degradation of streaming multimedia data

4. 4 Introduction (cont’d) Popular Quality of Service (QoS) guarantee mechanisms –Differentiated Service (DiffServ) [2] Guarantees aggregated QoS for multiple flows Can not guarantee specific QoS requirement for each data flow –Integrated Service (IntServ) Network resource reservation for specific data flow Strict guarantees for multimedia streams with various QoS requirements Resource Reservation Protocol (RSVP) [3]

5. 5 Introduction (cont’d) Problems of RSVP in Mobile Internet –Mobile Host (MH) handoff invalidates existing reservation paths  overhead and delay to re-establish new RSVP session –Movement to congested wireless cell  fail to get admission to re-establish new RSVP session  Seamless QoS guarantees are impossible Existing approaches –Mobile RSVP (MRSVP) [15] –Hierarchical Mobile RSVP (HMRSVP) [16] –A method of Concatenation and Optimization of Reservation Path (CORP) [10]

6. 6 Related Work Priority-based scheduling for MPEG streaming on Mobile Internet –Differentiated delivery service depending on the importance of each MPEG frame data R1 FA CH I B B P I B P B I P Priority-aware MPEG Server MH : MPEG video stream : Non-multimedia Traffic Packet drop MPEG Client congested

7. 7 Related Work (cont’d) Classify IP packets into two classes depending on its payload –Class 1: containing MPEG and GOP header (priority 1) –Class 2: containing MPEG I frame (priority 1) –Class 3: containing MPEG B, P frame (priority 7, best-effort) Uses TOS field in IP packet header as a classifier …. 4-bit version header len. 8-bit TOS field 16-bit total length (in bytes) 16-bit identification 3-bit flag 13-bit fragment offset 8-bit time-to-live (TTL) 8-bit protocol 16-bit header checksum 32-bit source IP address 01631 3-bit precedence field (currently ignored) minimize delay maximize throughput maximize reliability minimize monetary cost 1-bit unused 4 TOS bits

8. 8 Related Work (cont’d) Priority-aware MPEG streaming server

9. 9 Related Work (cont’d) Mobile IP Foreign Agent (FA) –Is the most probable spot of packet loss due to the network congestion –Acts as a gateway router for its own wireless subnet –Runs mobile IP FA daemon program –Performs priority-based CBQ scheduling for the traffic delivered toward MH Mobile MPEG client –Plays MPEG video stream from the server Advantages –Simple and light-weight mechanism  suitable for wireless/mobile networking environment –Significant video quality improvement can be achieved though the extra bandwidth is scarcely consumed

10. 10 Related Work (cont’d) Testbed configuration Non-diffserv router R HA FA MH Backgroundtraffic Priority-aware MPEG server MPEG video stream Priority-based scheduling on/off Wireless subnet 1 Wireless subnet 2 Experiment scenario Sample MPEG file specification Background traffic pattern File size1.2 Mbytes Playing out Duration 48 sec Frame rate30 fps Avg. bit rate214 Kbps Containing Frames 102 I, 404 P, 1010 B * Total 1516 frames 1516 frames ** The bandwidth limit in the WaveLAN II wireless link: 5.07 Mbps

11. 11 Related Work (cont’d) Experimental results –Number of the received packets (at client) containing either MPEG header or I-frame (Class 1, 2) Each packet size: 1024 bytes Total number of Class 1 or 2 packets: 151 Number of the received packets: 151 (the proposed mechanism), 121 (FIFO scheduling) –Transfer rate variation of the MPEG video stream Transfer rate is more independent on the amount of the background traffic (  ) Class 1, 2 packets are served by the priority-based scheduling

12. 12 Related Work (cont’d) Experimental results (cont’d) –PSNR value distribution Amount of the received traffic: 824 Kbytes (FIFO), 852 Kbytes (CBQ) out of total 1.2 Mbytes Number of frames  20 dB: 919 (FIFO), 775 (CBQ) Number of frames with 78 dB: 151 (FIFO), 192 (CBQ) 78 dB: same quality with the original image  20 dB: impossible to be recognized by human eyes Out of total 1440

13. 13 Related Work (cont’d) CORP –Base Station (BS) takes charge of making and managing RSVP sessions on behalf of MH –Consists of two main processes Concatenation of Reservation Path (CRP) process –Reservation path extension technique –Current BS pre-establishes pseudo reservation path (PRP) toward its neighboring BSs to prepare for MH’s handoff –When MH handoffs, corresponding PRP is activated to guarantee QoS for MH Optimization for Reservation Path (ORP) process –Solves infinitely long path extension problem and reservation path loop problem of CRP process –Optimizes the extended reservation path

14. 14 Related Work (cont’d) CRP Process BS_CBS_BBS_A I.MH requests a new RSVP session and BS_B makes it on behalf of the MH II.BS_B sends CRP inform messages to its neighbors CRP inform CORP message RSVP session PRP Activated PRP

15. 15 Related Work (cont’d) CRP Process BS_CBS_BBS_A I.MH requests a new RSVP session and BS_B makes it on behalf of the MH II.BS_B sends CRP inform messages to its neighbors III.BS_B makes PRP to its neighbors CORP message RSVP session PRP Activated PRP

16. 16 Related Work (cont’d) CRP Process BS_CBS_BBS_A I.MH requests a new RSVP session and BS_B makes it on behalf of the MH II.BS_B sends CRP inform messages to its neighbors III.BS_B makes PRP to its neighbors IV.MH handoffs toward BS_C’s cell CORP message RSVP session PRP Activated PRP

17. 17 Related Work (cont’d) CRP Process BS_CBS_BBS_A I.MH requests a new RSVP session and BS_B makes it on behalf of the MH II.BS_B sends CRP inform messages to its neighbors III.BS_B makes PRP to its neighbors IV.MH handoffs toward BS_C’s cell CRP activate V.BS_C sends CRP activate message to the previous BS (BS_B) CORP message RSVP session PRP Activated PRP

18. 18 Related Work (cont’d) CRP Process BS_CBS_BBS_A I.MH requests a new RSVP session and BS_B makes it on behalf of the MH II.BS_B sends CRP inform messages to its neighbors III.BS_B makes PRP to its neighbors IV.MH handoffs toward BS_C’s cell V.BS_C sends CRP activate message to the previous BS (BS_B) VI.BS_B forwards MPEG-1 video through the activated PRP CORP message RSVP session PRP Activated PRP

19. 19 Related Work (cont’d) CRP Process BS_CBS_BBS_A I.MH requests a new RSVP session and BS_B makes it on behalf of the MH II.BS_B sends CRP inform messages to its neighbors III.BS_B makes PRP to its neighbors IV.MH handoffs toward BS_C’s cell V.BS_C sends CRP activate message to the previous BS (BS_B) VI.BS_B forwards MPEG-1 video through the activated PRP VII.BS_B terminates useless PRP toward BS_A CORP message RSVP session PRP Activated PRP

20. 20 Related Work (cont’d) ORP Process BS_CBS_BBS_A CORP message RSVP session PRP Activated PRP I.BS_C sends IGMP group report message to its gateway router IGMP report

21. 21 Related Work (cont’d) ORP Process BS_CBS_BBS_A CORP message RSVP session PRP Activated PRP I.BS_C sends IGMP group report message to its gateway router II.BS_C joins into the existing multicast RSVP session CRP release III.BS_C sends CRP release message to the previous BS (BS_B)

22. 22 Related Work (cont’d) ORP Process BS_CBS_BBS_A CORP message RSVP session PRP Activated PRP I.BS_C sends IGMP group report message to its gateway router II.BS_C joins into the existing multicast RSVP session III.BS_C sends CRP release message to the previous BS (BS_B) IV.BS_B terminates the activated PRP and BS_C uses the newly optimized one to deliver MPEG data stream to MH

23. 23 Related Work (cont’d) ORP Process BS_CBS_BBS_A CORP message RSVP session PRP Activated PRP I.BS_C sends IGMP group report message to its gateway router II.BS_C joins into the existing multicast RSVP session III.BS_C sends CRP release message to the previous BS (BS_B) IV.BS_B terminates the activated PRP and BS_C uses the newly optimized one to deliver MPEG data stream to MH V.BS_B leaves the multicast RSVP session CRP inform CRP inform VI.BS_C sends CRP inform messages to its neighbors to prepare MH’s probable movement

24. 24 Proposed Mechanism Motivation –To provide QoS guarantees for MPEG video streaming services with mobility support Proposed System –Uses CORP to guarantee seamless QoS in mobile networks –Provides MPEG-1 video streaming services over CORP –CORP-aware video streaming server and client –CORP-capable mobile agents (Base Stations)

25. 25 System Design Video Server Architecture –CORP adaptation module handles CORP messages and takes charge of resource reservation process –MPEG-1 traffic transfer module transfers MPEG-1 stream to BS at the speed of a reserved bandwidth CORP message MPEG-1 data

26. 26 System Design (cont’d) Base Station Architecture –CORP message handler module handles CORP messages which are generated by neighboring BSs or a mobile client –traffic forward module receives MPEG-1 streaming data from the video server and forwards it to a neighboring BS or directly delivers it to the client

27. 27 System Design (cont’d) Client Architecture –CORP adaptation module handles CORP messages –Handoff detection module detects a handoff and determines when MH has to request the activation of PRP –MPEG-1 traffic receiver module receives MPEG-1 streaming data from a current BS –MPEG-1 video playback module plays the MPEG-1 video from the received stream

28. 28 System Design (cont’d) MPEG-1 Service Procedure over CORP before Handoff Video ServerBS1ClientBS2 Service Request Service Request Ack Service Request Service Request Ack RSVP path RSVP resv MPEG-1 traffic PRP establishment Client Handoffs (BS1  BS2)

29. 29 System Design (cont’d) MPEG-1 Service Procedure over CORP after Handoff Video ServerBS1ClientBS2 Client handoffs CRP Activate Request CRP Activate CRP Activate Ack MPEG-1 traffic ORP Request ORP Request Ack RSVP path RSVP resv MPEG-1 traffic (BS1  BS2)

30. 30 Testbed Configuration Network Architecture Wired subnet bandwidth 10 Mbps Ethernet Wireless subnet bandwidth IEEE 802.11b wireless LAN with the bandwidth of 11 Mbps BS Runs FA daemon of Mobile IP Runs CORP daemon Client Runs MH daemon of Mobile IP Runs VOD client program Video Server Supports CORP-aware MPEG-1 streaming service MH BS2 Gateway BS1 Video Server Wireless Subnet_1Wireless Subnet_2 Wired Subnet_1Wired Subnet_2 Home Agent

31. 31 Experiments Experiment Scenarios –Background traffic generation: MGEN –Maximum throughput of wired network: 9.34 Mbps –Wired subnet_1: non-congested –Wired subnet_2: congested 8.2 Mbps background traffic –Movement of MH: BS1  BS2 Experiment Cases I.MPEG-1 streaming with CORP and TCP II.MPEG-1 streaming with TCP only III.MPEG-1 streaming with CORP and UDP IV.MPEG-1 streaming with UDP only Shrek Resolution352 X 288 Average Data Rate (Mbps) 1.39 Frame Rate (fps)25 Play out duration (sec) 80 Total number of frames 2,000 Sample Video Clip Specification

32. 32 Performance Evaluation QoS Guarantee –Data rate is measured at client per each second while the sample MPEG file is being delivered –Not much difference in data rate distribution between before and after handoff cases in (I) –Amount of packet loss due to handoff is about 81Kbytes in (I) –84 percents are less than 0.3 Mbps after handoff in(II) I. MPEG-1 Streaming with CORP and TCPII. MPEG-1 Streaming with TCP only * 150KBps bandwidth reserved

33. 33 Performance Evaluation (cont’d) QoS Guarantee (cont’d) –Not much difference in data rate distribution between before and after handoff cases in (I) –Average data rate before handoff is significantly higher than that after handoff in (II) –Average packet loss rate is about 0.6 Mbps in (II) I. MPEG-1 Streaming with CORP and UDPII. MPEG-1 Streaming with UDP only * 200KBps bandwidth reserved

34. 34 Performance Evaluation (cont’d) Quality of Streaming Video –If Peak Signal to Noise Ratio (PSNR) is less than 20 dB, the frame can be regarded as being lost –In (I), MPEG-1 streaming data did not suffer from loss or delay under the congested situation –11 frames were lost during CRP process time in (I) –the total number of received frames is only 1107 frames out of 2000 frames for 80 seconds in (II) I. MPEG-1 Streaming with CORP and TCPII. MPEG-1 Streaming with TCP only

35. 35 Performance Evaluation (cont’d) Quality of Streaming Video (cont’d) –The average PSNR is 69.6 dB before MH’s handoff and 68.6 dB after MH’s handoff in (I) –MH could not play back MPEG-1 video stream correctly after handoff in (II) because of too high packet loss rate (0.6 Mbps) I. MPEG-1 Streaming with CORP and UDPII. MPEG-1 Streaming with UDP only

36. 36 Conclusions QoS guarantee for MPEG-1 streaming service in Mobile Internet –QoS guarantee mechanism with mobility support – CORP –Implementation of MPEG-1 streaming service over CORP Streaming Video Quality Improvement –Significantly better PSNR values in both cases of using TCP and UDP when CORP mechanism is applied –MPEG-1 streaming with CORP and TCP provided the highest video quality in the experiments Future work –Reduction in the packet loss during a handoff with CORP –Reduction in the packet loss over wireless links when UDP is used as a transport protocol