1. Multiple Addresses in Transport - For Discussion
Allison Mankin
Our vacation homes

2. 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

3. 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]

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

5. 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]

6. 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?

7. 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

8. 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.

9. 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?