Multiple Addresses in Transport - For Discussion

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Multiple Addresses in Transport - For Discussion

• Allison Mankin

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Setting

• Hosts have multiple addresses
• IPv4 (private realm or global)
• IPv6 (link-local, global)
• Multiple global addresses due to multi-homing
• Addresses of additional interfaces (e.g. SIGTRAN
  usages)
• Address obtained from STUN

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Multiple Addresses Tackled By Transports

• TCP not handling multiple addresses
• SCTP associations have multiple addresses and
  addip extension is working on its security
  tsvwg
• DCCP address (and port) mobility moved from base
  protocol to an extension document. This will
  probably be experimental. Mobility means
  changing from one of your addresses to another.
  dccp

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Note

• The handler of the addresses in the protocols
  just mentioned is the session layer.
• We just happen to combine session with transport.

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Session and ?? Protocols

• SIP with an SDP ANAT group in the offer-answer,
  one IPv4 and one IPv6 address are offered for
  connection choices. (Proposed work). mmusic
• ICE (Internet Connectivity Establishment) uses
  diagnostics to find a global address UDP only.
  Other transports TBD. mmusic
• NSIS nat/firewall traversal application is
  considering a multi-address model. Output would
  be the reservation whose nat count had been
  lowest (Proposed work) nsis

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Crux of the Discussion

• The transport area has multiple approaches to
  multiple addresses
• Varied services, differing breadth
• Then there are multi-homing and host identity
  protocol (in the ops and internet areas)
• Can/need we make this more consistent?

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Multi6 and HIP

• Multi6 (OPS Area) and HIP (INT Area)
• Original tens of proposals with tens of goals are
  coming down to some coherence
• Largest goal of scaling the routing system for
  multi-homing, with some other benefits
• My view
• Survival long-lived transport not goal

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Multiple Addresses in Multi6/HIP

• NOID Identifier is one of the global IPv6
  addresses, other addresses are locators and are
  not seen.
• HIP/WIMP Identifier is internal application
  only.
• Main point is that all mask locators from session
  layer.

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Conclusions/Directions

• Generalize, use some transport work more? ICE?
• Is the identifier work compatible with transport,
  session layer goals?
• Should there be transport elements of source
  address selection (when connectivity gives
  multiple choices)?
• Which layers should determine address selections
  and why?