ASM On SSM

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ASM On SSM

• Hongqiang Liu
• 2007/4/18

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Background

• Any Source Multicast (ASM)
• Anyone can be a sender of a ASM group
• A ASM Multicast IP indicates one group (service)
• (,G)
• Source Specific Multicast (SSM)
• Only one can be a sender of a SSM group
• A SSM Multicast IP and a source unicast IP
  indicate one group (service)
• (S,G)

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Problem in IPv6 Multicast

• CERNET2
• Only support SSM in the backbone
• Internet, 6NET, Euro6IX and JGN2
• All support SSM
• ASM?

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ASM On SSM Gateway Proxy

• We CAN NOT
• change anything in ASM applications
• change anything in routing policies in router
• We CAN
• deploy a proxy in every ASM Island
• distribute IPv6 addresses in every ASM Island
• Requirements
• It can serve all over world in IPv6 Internet
• The number of senders is limited (100), and one
  ASM island can have more than one senders
• The number of receivers is not limited
• In network which do not support Multicast, go on
  unicast

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A View of the System
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Steps To The Goal

• IP Addresses Mapping
• Mapping ASM address to SSM address
• Mapping different senders in an ASM island to
  sender ID
• Mapping different gateways to different gateway
  ID
• Mapping data from different sources to gateways
  different unicast addresses
• Distinguishing the data senders
• Data transmitting
• Administration mechanism
• Only support the services which are registered
• Flow control
• Security

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IP Addresses Mapping

• Mapping ASM address to SSM address
• Mapping different senders in an ASM island to
  sender IDs
• A Gateway forwards the packets from different
  senders to other gateways using different UDP
  ports
• The packets received from the same gateway but
  different sending ports will be treated as data
  from different senders
• Mapping different gateways to different gateway
  IDs
• There is also gateway ID that identifies every
  gateway.
• It is distributed by administration server and is
  unique
• It is used by a gateway when it sends data to the
  ASM island under his service to identify
  different sources
• Mapping sources to gateways different unicast
  addresses
• 2001da82009002/114

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Summary of Ad Mapping
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Administration Mechanism

• Administration Server
• Tells all the gateways which SSM groups (S,G) to
  join in
• Distributes gateway IDs
• Only serves the groups who have its permission

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Administration Mechanism

• SSM_Addr_Currently.html
• SSM Addr ff3x1234
• Souce (GateWay Addresses)
• S12001da820090023fff ID1
• S22002da820090023fff ID2

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Gateway and Administration Server

• Gateways GET the SSM addresses and sources list
  in a proper period to update the multicast group
  it is joining
• A Gateway GET is also a keep-alive message for
  the core server. If a Gateway do not GET from the
  core server until timeout, core server will throw
  it from the sources list
• A Gateway can request not to be in any SSM group

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Work By Now

• Read RFCs and papers to study SSM and ASM
• Survey related work
• Design a framework to meet our demands
• Build a software structure following the
  framework
• Code the functions in detail
• Bridge Unicast and Muticast

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THANKS