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ICE 798 Wireless Mobile Internet – Fall 2002 Term Project. The implementation of video distribution application using mobile group communication. December 4, 2002 CDS&N Lab., ICU Dukyun Nam. Introduction. Group Communication Service [6, 11]
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ICE 798 Wireless Mobile Internet – Fall 2002 Term Project The implementation of video distribution application using mobile group communication December 4, 2002 CDS&N Lab., ICU Dukyun Nam
Introduction • Group Communication Service [6, 11] • a collection of processes forms a fault-tolerant group and cooperatively performs a distributed computation using group communication protocols that guarantee message delivery ordering (process group & group programming tools) • Group membership • It hides from application the internal coordination of a group • Consistency of view • Reliable multicast • It delivers a single message to multiple receivers • Atomicity • Ordering • Consideration in wireless environment • Unreliable communication • Handoff • Disconnected mode & Idle mode • Disconnection is distinct from failure • No long-run application in mobile • Join/Leave operation is occurred frequently • Mobile Group Communication Service [10]
Motivation • Killer application of group communication? • Replication to support fault tolerance • Try to support multimedia data in this project • Multimedia data • Video, Audio, Text, etc. • MPEG-1 Video in this project • Timeliness • Wireless environment • Loss rate in wireless networks is higher than in wired networks • Group communication can provide QoS to end users
Background • MPEG video data [9] • Consists of I frame, B frame, and P frame • I (interframe), P (predicted), B (bi-directional) • Priority: I > P > B MPEG Data Frames
Related work • Group Communication in mobile environments • MobileChannel [7] • Hides handoff using group communication • Using primary migration • Prakash and Baldoni’s approach [13] • Proximity layer • For location awareness • Group Multicast [1, 5] • Coordinator based approach • Disconnected member : automatically recover if reconnected • Existing group communication systems in WANs [3, 4, 8] • Paritionable network • Support split and remerging
Related work (cont.) • Mobile Group Communication Service [10] • Designed by ICU CDS&N Lab. • Underlying protocol • UDP, not IP multicast MGCS Architecture
Design • Sample environments • Source • In wired networks • Sink • In wireless networks • Loss rate is high Sample environments
Pack start code Pack header Packet Packet End code Packet start code Packet header Packet data Start Code I frames P frames B frames Receiver 1 Sender Receiver 2 MPEG Receiver 3 Design (cont.) • MPEG Data • Packs: collection of packets • Data delivery Structure of MPEG data Data delivery of MPEG frames
Local decoding Mpeg stream Partitioning stream stream … stream stream stream Start point End point Implementation • MPEG player [12] • JDK 1.3 • Procedure • 1) Loading and parsing of the MPEG-files • 2) Reconstruction of the single frames • 3) Playing of the frames as animation in a thread • Group communication protocol • MGCS [10] MPEG data partitioning
Demonstration • MPEG video data delivery using MGCS • Environments • Assume high loss rate networks • Use small size MPEG file • Case 1 • Use IP multicast • B frames are lost • Case 2 • Use MGCS • I-, B-, P-frames are delivered Source Sink IP multicast Source Membership Server MSS MGCS Sink
Conclusion • Video distribution application using MGCS • Guarantee reliable data exchange among members in wireless networks • MGCS’s errors are fixed, but not completed. • Implementation problems of MGCS • Buffer management • Packet fragmentation • Future work • Fix bugs of MGCS • Performance evaluation • MGCS and video distribution application • Reliable delivery vs. playing time • Test this application in the wireless test-bed
References [1] G. Anastasi, A. Bartoli, and F. Spadoni, “Group Multicast in Distributed Mobile Systems with Unreliable Wireless Network,” Proceedings of the 18th IEEE Symposium on Reliable Distributed Systems, pp. 14-23, October 1999. [2] T. Anker, D. Dolev, and I. Keidar, “Fault Tolerant Video on Demand Services,” Proceedings of the 19th International Conference on Distributed Computing Systems, pp. 244-252, June 1999. [3] Ö. Babaoğlu, R. Davoli, L.-A. Giachini, and M.G. Baker, “RELACS: A Communication Infrastructure for Constructing Reliable Applications in Large-Scale Distributed Systems,” Proceedings of the 28th Annual Hawaii International Conference on System Sciences, pp. 612-621, January 1995. [4] Ö. Babaoğlu, R. Davoli,, and A. Montresor, “Group Communication in Partitionable Systems: Specification and Algorithms,” IEEE Transactions on Software Engineering, 27 (4), pp. 308-336, April 2001. [5] A. Bartoli, “Group-based multicast and dynamic membership in wireless networks with incomplete spatial coverage,” ACM/Baltzer Mobile Networks and Applications, 3 (2), pp. 175-188, June 1998. [6] K.P. Birman, “The Process Group Approach to Reliable Distributed Computing,” Communications of the ACM, 36 (12), pp. 37-53, December 1993. [7] K. Cho and K.P. Birman, “A Group Communication Architecture for Mobile Computing,” Proceedings of Workshop on Mobile Computing Systems and Applications, pp.95-102, December 1994. [8] D. Dolev and D. Malki, “The Transis Approach to High Availability Cluster Communication,” Communications of the ACM, 39 (4), pp. 64-70, April 1996. [9] D.L. Gall, “MPEG: A video compression standard for multimedia applications,” Communications of the ACM, 34(4), pp. 46-58, 1991. [10] B. Kim, D. Lee, and D. Nam, “Scalable Group Membership Service for Mobile Internet," Proceedings of the Seventh IEEE International Workshop on Object-oriented Real-time Dependable Systems (WORDS 2002), pp. 295-298, January 2002. [11] L.E. Moser, Y. Amir, P.M. Melliar-Smith, and D.A. Agarwal, “Extended Virtual Synchrony,” Proceedings of the 14th International Conference on Distributed Computing Systems, pp. 56-65, June 1994. [12] MPEG-1 Java Player site, http://rnvs.informatik.tu-chemnitz.de/~ja/MPEG/MPEG_Play.html [13] R. Prakash and R. Baldoni, “Architecture for Group Communication in Mobile Systems,” Proceedings of the 17th IEEE Symposium on Reliable Distributed Systems, pp. 235-242, October 1998.