Re: [multipathtcp] Multipath Address Family

[Olivier Bonaventure <[e-mail]>]

Pasi,
> 
> (changed the topic line, it was earlier "API: which address to use". I'm
> responding to Yoshifumi below, but first wanted to post a general note.)
> 
> I wrote down some further thinking about the idea of multipath address
> family in the form of Internet-Draft, which I thought to be better than
> a long Email to the list. The draft is available at
> http://tools.ietf.org/html/draft-sarolahti-mptcp-af-multipath-00 and I'd
> be happy to hear further comments about it.
> 
> I think a new address family would be a minimal needed change to the
> current socket API, without extending the API with new operations, but
> yet provide an interface to handle multiple addresses in a socket. One
> potentially useful characteristic would be that this would allow name
> resolver to return multiple IPv4 and/or IPv6 addresses from the name
> server as a single sockaddr structure, that could be directly given as a
> parameter to a connect call, which would lead to trying which of the
> addresses are reachable for the MPTCP session. Traditionally this has
> been done in the applications, by cycling through the returned addresses
> from resolver one by one, until connect is successful. Especially
> dual-stack IPv6/IPv4 hosts should find such feature useful.

This could be interesting, but if we change de socket API, why don't we
define a new structure that can handle DNS names in addition to IPv4 and
IPv6 addresses. This would allow some applications to simply call
connect with a DNS name and let the transport protocol figure out
whether single path IPv4, single path IPv6, multipath whatever ...
should be used to reach this DNS name.


Olivier

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