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Delve into the world of multiple addresses in transport protocols, encompassing IPv4, IPv6, multi-homing, and address selection challenges. Analyze the evolving landscape of session and transport layer integrations, with a focus on scalability and consistent frameworks.
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Multiple Addresses in Transport - For Discussion Allison Mankin
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
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]
Note • The handler of the addresses in the protocols just mentioned is the session layer. • We just happen to combine session with transport.
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]
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?
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
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.
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?