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MPTCP Protocol – Status Update draft-ietf-mptcp-multiaddressed-01. Alan Ford alan.ford@roke.co.uk IETF 78 – Maastricht. What’s happened since IETF77?. draft-ford-mptcp-multiaddressed adopted as WG item Technical additions to -00 Textual changes to -01. Differences since IETF77.
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MPTCP Protocol – Status Updatedraft-ietf-mptcp-multiaddressed-01 Alan Fordalan.ford@roke.co.uk IETF 78 – Maastricht
What’s happened since IETF77? • draft-ford-mptcp-multiaddressed adopted as WG item • Technical additions to -00 • Textual changes to -01
Differences since IETF77 • Editorial changes: • Terminology moved later • Address signalling moved later • Heuristics begun to be separated • Options given more sensible names • Explicitly stated fallback at handshake • Clarifications of window/DATA_ACK algorithms • Clarified separation of subflow- and connection-level processing (also for buffer management)
Differences since IETF77 (2) • Add Port to ADD_ADDR • Path liveness check in REM_ADDR • Checksum in DSN_MAP, leading to… • Mid-connection fallback mechanism: • Closing affected subflows • If there is only one subflow, it is possible to fall-back without restarting • Middlebox discussion improved
Detecting Content-Changing Middleboxes • Identified as a major issue at IETF77 • We don’t want to prevent such boxes • Allowing e.g. address translation is not directly a problem for MPTCP • The problem is with losing DSN_MAP sync • So, checksumming allows detection of changes to the content of DSN_MAP content • But is this the best way? • It’s relatively expensive, rarely needed, and potentially difficult for offload engines • Open to other ideas • Hot off the press: copy last payload byte(s) to DSN_MAP?
What now? • Open issues: • Subflow policy • Handshake security – hash chains? • Middlebox compatibility • Making some components optional? • A lightweight subset of features for specialised, controlled use cases, e.g. data centres • Reviews please!