AG connect: Toward better connectivity for the AG

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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_at_netmedia.gist.ac.kr
• http//ace.netmedia.gist.ac.kr/

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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

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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

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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 ISPs control
• Multicast failures compromise the usability of
  the Access Grid

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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

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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

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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

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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

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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

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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

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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
  isnt 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 AGs structure to provide
  storage for multiple multicast addresses

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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

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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

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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

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Modified QuickBridge (2/2)
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Implemented Result
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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

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Gwangju Institute of Science Technology
Thank you!
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e.netmedia.gist.ac.kr/