Multipath TCP Architecture (draft-ietf-mptcp-architecture-00)

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Multipath TCP Architecture(draft-ietf-mptcp-archi
tecture-00)

• Alan Ford
• alan.ford_at_roke.co.uk

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Since IETF76...

• draft-ford-mptcp-architecture-01 discussed at
  Interim Meeting (February)
• Consensus on many open issues
• Resolved as changes between draft-ford-mptcp-archi
  tecture-01 and draft-ietf-mptcp-architecture-00
• Adopted as WG document

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Purpose of Draft

• Overview of MPTCP
• Motivation and goals for Multipath TCP
• Functional architecture
• Consensus on high-level design decisions
• How components (drafts) fit together

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High-level Design Decisions(Consensus Verified
at Interim)

• Two layers of sequence numbering
• Retransmissions
• MUST be permitted on alternative subflows
• Original holes SHOULD still be filled
• Paths identified by IP address pairs
• MPTCP connection have separate identifier
• Support for v4 and v6 (even in same connection)
• New content in protocol draft for middleboxes,
  buffers and windows

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New Decisions at Interim

• Requirement to add DATA ACK
• Adds robustness end-to-end ACK
• Legacy application compatibility
• i.e. presentation of IP address pairs
• This is not something for the WG to mandate
• It is up to the OS vendors to decide how to
  behave with legacy apps once the impact has been
  assessed

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Other Changes from Previous Version

• Major clarifications throughout motivation and
  goals sections
• Significant details on transport layer
  decomposition
• Middleboxes can split connections at IP or TCP
  layer
• Clarifications throughout the document

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Any questions?