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AG connect: Toward better connectivity for the AG

AG connect: Toward better connectivity for the AG. 19 th APAN Bangkok Meeting (2005. 1. 25) Namgon Kim and JongWon Kim Networked Media Laboratory Dept. of Information & Communications Gwangju Institute of Science & Technology (GIST) jongwon@netmedia.gist.ac.kr

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AG connect: Toward better connectivity for the AG

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  1. AG connect: Toward better connectivity for the AG 19th APAN Bangkok Meeting (2005. 1. 25) Namgon Kim and JongWon Kim Networked Media Laboratory Dept. of Information & Communications Gwangju Institute of Science & Technology (GIST) jongwon@netmedia.gist.ac.kr http://ace.netmedia.gist.ac.kr/

  2. Contents • Access Grid (AG) • AG Connectivity Problems • Unicast networks • Networks behind Firewall and NAT • Low capacity nodes • Connectivity Solution for High-Quality Video • Structure of High-Quality Video for AG • Modification of AG Structure • Modified QuickBridge • Implemented Result • Conclusion

  3. Access Grid (AG) • Support group-to-group interaction across the Grid • Access Grid does for people what the computational Grid does for machines • Much more than teleconferencing, if possible at commodity prices • To enable groups of people to interact with Grid resources and to use the Grid technology to support group to group collaboration at a distance • Distributed Lectures and seminars • Remote participation in panel discussions • Virtual site visits meetings • Complex distributed grid based demonstrations

  4. AG Connectivity Problems (1/3) • Multicast Connectivity • Access Grid uses multicast for multimedia delivery • Multicast is bandwidth efficient • Multicast-disabled networks • Unicast networks • Networks under ISP’s control • Multicast failures compromise the usability of the Access Grid

  5. AG Connectivity Problems (2/3) • Firewall and NAT transition • Firewall • Packet filtering and Protocol end point • A multicast packet sent over the Internet will never be seen on the intranet, unless such packets are explicitly relayed by the firewall • NAT (Network Address Translation) • Unidirectional connection initiation only • Only hosts behind NAT can initiate the connection

  6. AG Connectivity Problems (3/3) • Problems due to low capacity for data • System is under multicast-enabled network • But due to lack of capacity, have difficulties in handling data • Nodes under Low network bandwidth • Nodes in small network bandwidth can not receive multimedia data • Nodes with Low performance System • Nodes with poor system performance can not process received data

  7. AG Connector • Vision of AG Connector • A solution for all these connectivity problems • AG Connector for Unicast Nodes • AG Connector for Networks behind firewall • AG Connector as a proxy • For users with low system performance • For users with low network bandwidth

  8. Connectivity Solutions for High-Quality Video • Modify QuickBridge to support AG with High-Quality Video • A connectivity solution for AG with High-Quality Video • AG with High-Quality Video • Limitation of current Access Grid Toolkit (2.1.x) • Low-resolution VIC-based video (300Kbps CIF sized image) • High-Quality video services for Access Grid Toolkit is developed to promote advanced collaboration environment • HDV (1280x720)/DV(720x480) support • Motivation • Current QuickBridge of AG is not applicable to AG with High-Quality Video • AG with High-Quality Video is using two multicast addresses • Session multicast address • Video multicast address • Modify QuickBridge to provide connectivity solution for AG with High-Quality Video

  9. AG Node Versatile Video Formats HDV AG Node Multicast-enabled Network DV AG Node Stereo Structure of High-Quality Video for AG • Motivation • Limitation of existing video services in supporting high-quality video • Features • Versatile Video Format Support • Multimedia Session Management • Enable AGTk to support various video formats via an unified interface

  10. Select Video 1, 3 Multicast 1 Multicast 2 Video stream 1 Video stream 2 Multicast 4 Multicast 3 Video stream 4 Video stream 3 Flexible Multicast Address Allocation • A Shared multicast address for every Video Consumer Service • Session multicast address • Video Consumer service gets video stream list from session multicast address • A unique multicast address per each Video Producer Service • Video multicast address • Let each AG node can receive video streams selectively. • Can allow the sender share multicast address, if it is required

  11. Lack of Multicast Bridge Service • To utilize flexible multicast address allocation, High-Quality Video for AG modifies structure of AG • Uses more than two multicast addresses for one High-Quality Video Session • Modified Structure of High-Quality Video for AG isn’t compatible with current AG Structure • Current AG uses only one multicast address for a session • QuickBridge is only for one shared multicast address • To provide Multicast Bridge Service, AG must store two kinds of info. • One for session multicast address, the other for video multicast address • Need to modify current AG’s structure to provide storage for multiple multicast addresses

  12. Modification of AG Structure • EVS (Extended Video Service) is the implementation of High-quality video service • Modification of Access Grid • Modify EVS Stream Description to store these two bridges’ information • Execute video application using information received from SAP (Session Announcement Protocol) • Provide a way for high-quality video producer to keep its video multicast address • Modification of QuickBridge • Modify QuickBridge of AG to create multicast bridge for each multicast address • Stores mapping information between multicast address and unicast address • Multicast Bridge for session multicast address does translation of SAP message • Translate SAP message to fit the connection type of consumer

  13. EVS Stream Description • EVS Stream Description • Modify EVS Stream Description to store Multicast Bridge information for EVS Stream • Provide a way for high-quality video producer to keep its video multicast address • Bridge Server • Modify Bridge Server to create Bridge for two multicast addresses of EVS

  14. Modified QuickBridge (1/2) • Bridge Server stores Bridge information when it makes a new Bridge • Information about the relation between multicast address and unicast address • Unicast Mappings • Multicast Mappings • Bridge for Session multicast address • Analyzes session information, and transforms it according to the network connection type of EVCS • For a EVCS which uses multicast bridge, Bridge sends all information as unicast form • For a EVCS which uses multicast, Bridge sends all information as multicast form

  15. Modified QuickBridge (2/2)

  16. Implemented Result

  17. Conclusion • Connectivity Solution for High-Quality Video • Modify Quick Bridge to provide multicast bridge to High-Quality Video for AG • Access Grid • Modify EVS Stream Description to store these two bridges’ information • Execute video application using information received from SAP • QuickBridge • Create multicast bridge for each multicast address • Translate SAP message to fit the connection type of consumer • Future Work • Implement AG Connector • Use tunneling with Encapsulation • Provide connection with AG by Shared Application

  18. Gwangju Institute of Science & Technology Thank you! Send Inquiry to ace@netmedia.gist.ac.kr http://ace.netmedia.gist.ac.kr/

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